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PIXIE-4 Online Help

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1. Se ee 2 3 2014 Pixie 4 Online Help 26 4 modules 16 h0400 MC lt amp hitOs 3 0 I 1 specific channel hit in each of 4 specific modules others don t matter 16 h0401 MC lt amp hitOs 3 0 amp amp hit1s 3 0 2 specific channels hit in each of 4 specific module others don t matter 5 modules 16 h0500 MC lt amp hitOs 4 0 Il 1 specific channel hit in each of 5 specific modules others don t matter 16 h0501 MC lt amp hitOs 4 0 amp amp hit1s 4 0 2 specific channels hit in each of 5 specific module others don t matter 6 modules 16 h0600 MC lt amp hitOs 5 0 Il 1 specific channel hit in each of 6 specific modules others don t matter 16 h0601 MC lt amp hitOs 5 0 amp amp hit1s 5 0 2 specific channels hit in each of 6 specific module others don t matter 7 modules 16 h0700 MC lt amp hitOs 6 0 Il 1 specific channel hit in each of 7 specific modules others don t matter 16 h0701 MC lt amp hitOs 6 0 amp amp hit1s 6 0 2 specific channels hit in each of 7 specific module others don t matter 8 modules 16 h0800 MC lt amp hitOs 7 0 Il 1 specific channel hit in each of 8 specific modules others don t matter 16 h0801 MC lt amp hitOs 7 0 amp amp hit1s 7 0 2 specific channels hit in each of 8 specific module others don t matter I1 9 modules 16 h0900 MC lt amp hitOs 8 0 Il 1 specific channel hit in each
2. and the fast trigger filter together with an estimate of the trigger threshold The display is updated through its Refresh button Notes 1 For best representation of the filters the filter lengths should be an integer multiple of the ADC sampling interval 2 Only a simple trapezoidal difference filter is shown for the energy filter In the actual pulse height calculation corrections are applied that take into account the decay of previous pulses the contribution during the flat top time and long term baseline effects Manual Fit Decay Time Manual Tau Fitting is done on a channel by channel basis First set the cursors on the trace to fit If possible some of the baseline after the pulse should be included in the fit region Use Ctrl I to show the cursors at the bottom of the graph if they are not already visible Clicking into the Fit Trace popup menu lets you select the channel to fit The result is shown in the field Tau below If acceptable use the Accept popup menu to assign the fit result to a channel Clicking Remove Tau Fit will remove the fit function and residuals from the graph 2 3 2014 Pixie 4 Online Help 18 e CopyPanel This panel can be used to copy parameter settings from one module to another The source module and channel are selected at the top of the panel The parameters to be copied are organized into list box in the left hand column The right hand column shows the destination channels and
3. lt MOCO amp MOC1 amp MOC2 amp MOC3 M1CO amp M1C1 amp M1C2 amp M1C3 IL 3 specific channels hit in either module no others 16 h0203 MC lt MOCO amp MOC1 amp MOC2 amp MOC3 M1CO amp M1C1 amp M1C2 amp M1C3 Il 4 specific channels hit in either module no others 16 h0204 MC lt MOCO M1C0 Il 1 specific channel hit in either module others don t matter 16 h0205 MC lt MOCO amp MOC1 M1C0 amp M1C1 Il 2 specific channels hit in either module others don t matter 16 h0206 MC lt MOCO amp MOC1 amp M0C2 M1C0 amp M1C1 amp M1C2 Il 3 specific channels hit in either module others don t matter 16 h0207 MC lt MOCO amp M0C1 amp IMOC2 amp MOC3 M1C0 amp M1C1 amp IM1C2 amp M1C3 Il 1 specific channel hit in either not both modules no others 16 h0208 MC lt MOCO amp MOC1 amp IMOC2 amp MOC3 M1C0O amp M1C1 amp IM1C2 amp M1C3 Il 2 specific channels hit in either not both modules no others 16 h0209 MC lt MOCO amp MOC1 amp MOC2 amp MOC3 M1CO amp M1C1 amp M1C2 amp M1C3 IL 3 specific channels hit in either not both modules no others 16 h020A MC lt MOCO amp MOC1 amp MOC2 amp MOC3 M1C0 amp M1C1 amp M1C2 amp M1C3 Il 4 specific channels hit in either not both modules no others 16 h020B MC lt MOCO M1C0 yy l 1 specific channel hit in eithe
4. this button the file series will begin with the current value this is useful to resume a file series Set Scan Run Conditions will set the checkboxes in the Data Record Options panel to the values required for the scan and set the run time to the total time required interval N in the Data Record Options panel times the number of settings At the bottom of the panel the button Start Scan starts the file series This is a different button from the standard Start Run button because it is starting a run which is modifying parameters All the updates during a run work the same as in a standard run though and the run can be stopped with the standard Stop Run button When the run is complete click on the File Series button to open the File Series panel for analysis e File Series The File Series Results panel is used to process a series of data files with consecutive run numbers There are control fields to enter the Basename as in the Run Control tab of the Parameter Setup panel and the Start and End end run number These numbers are inclusive i e Start 1 and End 10 processes files 1 10 Clicking Parse Files will read spectra from each file and perform a Gauss fit with the settings in the MCA Spectrum The results of the fit are plotted in the graph section The individual spectra are also accumulated into a total spectrum for each channel which at the end of processing replace the spectra shown in the MCA Spectrum
5. In addition the energy filter settings and the value for the decay time are read for each file from the associated ifm file and also plotted in the graph This can be used to find the optimum settings together with the function to scan filter settings described under File Series Scan 2 3 2014 Pixie 4 Online Help 22 e ChassisRegisterPanel The Chassis Setup Panel controls several system wide parameters Backplane Options Trigger share mode As described for the Trigger tab of the Parameter Setup panel if group trigger operation is requested each channel will respond to a distributed trigger rather than its own local trigger Triggers are always distributed within a module Any channel that is enabled to trigger will contribute to the distributed trigger and any channel in group trigger mode will only respond to the distributed trigger including those issued by itself In addition triggers can be distributed over the PXI backplane between modules The field Trigger share mode controls this distribution There are currently 4 modes In mode 0 the module is disconnected from the backplane Group triggers are only distributed between the 4 channels of the module In mode 1 the module is connected to the backplane s wired OR lines This means that any module in mode 1 issues triggers on common backplane lines and every module in mode 1 responds to these triggers Modes 2 and 3 are used in large chassis with more than 8 sl
6. current input count rate ICR and the current fraction of time the signal is out of range Out of Range These values are updated in the DSP every 2 3ms if a run is in progress or not Their precision is in the order of 5 10 or 50 cps FFTdisplay You can analyze the noise spectrum in the trace captured in the Oscilloscope by observing the Fourier transform of the signal For best results remove any source from the detector and only regard traces without actual events The chart shows a plot of amplitude vs frequency The plot is calibrated such that a sine wave with 100 ADC units amplitude 200 units peak to peak will show up with an amplitude of 100 To convert a noise floor measurement into ADC units sqrt Hz use the variable FFTbin displayed at the top of the chart which tells the width of each frequency bin in the Fourier spectrum The conversion from amplitudes to rms ADC units sqrt Hz is accomplished by multiplying with 1 sqrt 2 FFTbin Now observe that an ADC unit corresponds to 61uV Using the known gain of the Pixie 4 you can convert the noise into an input noise voltage density measured in V sqrt Hz Or given a particular energy calibration the noise density can be expressed as eV sqrt Hz If you click on the Apply Filter button you can see the effect of the energy filter simulated on the noise spectrum ADCFilterDisplay This graph shows the ADC trace for the selected channel and the response of the slow energy filter
7. do not need the ASCII data you can disable the dat file by unchecking the Auto process list mode data in the Data Record Options panel mca For both list mode runs and MCA runs MCA spectrum data are stored in a file with name extension mca if you select Auto store spectrum on the Data Record Options panel This is a binary file consisting of 32bit unsigned integers It includes MCA data for all modules ordered from channel 0 of module 0 to channel 3 of the last module set Module settings are stored in a file with name extension set after each run if you select Auto store settings on the Data Record Options panel Run statistics can also be extracted from this file This is a binary file consisting of 16bit unsigned integers It is equivalent to the settings files saved from the Settings tab ifm For both list mode runs and MCA runs run statistics information are stored in a file with the extension ifm if you select Auto store statistics in the Data Record Options panel List Mode Spill Settings Number of Spills In list mode runs since available memory limits the amount of data that each module can store the data has to be read out from time to time Each such readout is called a spill For a longer run in list 2 3 2014 Pixie 4 Online Help 14 mode you can request several spills For example if you request a run with 10 spills you will get 10 times the memory data At sta
8. modules for the copy operation The Items to copy shown on the Copy Panel and the actual variables to be copied are listed below Items Actual variables to be copied Gain Gain V V Offset Offset V and base percent Filter Energy Filter Rise Time and Flat Top Baseline Cut Trigger Trigger Filter Rise Time and Flat Top Trigger Threshold FIFO Trace Length Delay dT us PSA Start PSA End CFD Threshold ChanCSR Channel CSRA Channel CSRB Channel CSRC Coinc Coincidence Pattern Coincidence Window MCA Cut Off Energy Binning Factor TAU Tau us Intergrator Integrator ModCSR All module coincidence settings and backplane options except front panel GFLT After selecting source destination and parameters click on the Copy button to execute the copy operation ExtractPanel This panel can be used to extract parameter settings from a file to selected modules and channels The source file is specified at the top of the panel Click on the Find button to locate the source file Parameters to be extracted and destination modules or channels are selected in the same manner as in the CopyPanel Click the Extract button to execute the operation AIIFilesPanel This panel gives you access to the underlying files of the Pixie 4 software Usually these files are already loaded in the memory of the Pixie 4 Viewer You only have to change these files when you receive updates from XIA The directory lo
9. more efficient if MAXEVENTS takes into account 4 good channels per event but only few multi channel events occur in the acquisition the buffer will only be filled up to about 1 4 when MAXEVENTS is reached Setting Events Buffer to zero will always fill the buffer as much as possible It is ignored in MCA runs 1 32 16 16 Buffers per Spill List mode data is first accumulated in a buffer in internal DSP memory There are two options to use the larger external memory on the Pixie 4 to store several buffers and read them out in a fast block read These options reduce readout dead time because the block read is faster If the radio button 1 buffer per spill is selected the external memory is not used at all and the module stores only one buffer in internal memory The total number of events will be Events Buffer times the Number of Spills The readout deadtime will be higher in this mode If the radio button 32 buffers per spill is selected the module stores 32 data buffers in external memory which then are read out in a fast block read Each readout counts as one spill The total number of events will be 32 times the Events Buffer times the Number of Spills If the radio button 16 16 buffers is checked the module stores 16 data buffers in the first half of the external memory which then are available for read out in a fast block read while another 16 buffers are stored in the second half and so on Each readout of 16
10. not all described controls are visible click on the More button at the bottom of the panel Trace Capture The Trace Length and Trace Delay values entered in this group of controls both in units of us govern the waveform acquisition Trace Length is the total length of the acquired waveform which can be set independently of the parameters in the Energy and Trigger Filter You can use the delay parameter to move the trigger point within the trace Trace Delay measures the trigger time with respect to the beginning of the recorded trace The trace lengths are up to 13 6us for each channel and can be specified in 13 3ns increments The 4x longer traces checkboxes can be used to increase the captured waveforms by a factor of 4 Four samples are summed and stored in a single value every 53ns The Trace Length and Trace Delay values do not change when checking the box the factor 4 is implied not shown The RunFormat value in list mode data will have bits 4 7 set if the 4x longer traces are requested for channels 0 3 e g RunFormat 0x21F0 for a Pixie 4 data acquisition in which all channels record 4 times longer traces This serves as an identifier for any parsing or processing routine In the list mode traces display waveforms are scaled with correct dt the amplitude is in 16 bit units for all cases but waveforms are left aligned with the first sample so the trigger point appears to be shifted for the 4x longer waveforms If e
11. of 9 specific modules others don t matter 16 h0901 MC lt amp hitOs 8 0 amp amp hit1s 8 0 2 specific channels hit in each of 9 specific module others don t matter 10 modules 16 h0A00 MC lt amp hitOs 9 0 Il 1 specific channel hit in each of 10 specific modules others don t matter 16 h0A01 MC lt amp hitOs 9 0 amp amp hit1s 9 0 2 specific channels hit in each of 10 specific module others don t matter 11 modules 16 hOB00 MC lt amp hitOs 10 0 Il 1 specific channel hit in each of 11 specific modules others don t matter 16 h0B01 MC lt amp hitOs 10 0 amp amp hit1s 10 0 2 specific channels hit in each of 11 specific module others don t matter 12 modules 16 hOC00 MC lt amp hitOs 11 0 Il 1 specific channel hit in each of 12 specific modules others don t matter 16 h0C01 MC lt amp hitOs 11 0 amp amp hit1s 11 0 2 specific channels hit in each of 12 specific module others don t matter 113 modules 16 hOD00 MC lt amp hitOs 12 0 Il 1 specific channel hit in each of 13 specific modules others don t matter 16 h0D01 MC lt amp hitOs 12 0 amp amp hit1s 12 0 2 specific channels hit in each of 13 specific module others don t matter Il group tests 16 n1020 MC lt MSUM_g1 gt 2 2 or more modules in first group rest don t care 16 n1021 MC lt MSUM_g1 gt 2 MSUM_all gt 3 2 or mo
12. or more in either MC lt multi00 gt multi_req1 multi01 gt multi_req1 multi02 gt multi_req1 2 or more in either MC lt multi00 gt multi_req1 multi01 gt multi_req1 multi02 gt multi_req 3 or more in either MC lt multi00 multi_req1 multi01 multi_req1 multi02 gt multi_req1 1 each in either module MC lt multi00 multi_req1 multi01 multi_req1 multi02 gt multi_req1 2 each in either module MC lt multi00 multi_req1 multi01 multi_req1 multi02 gt multi_req1 3 each in either module MC lt MC lt MC lt MC lt pa00 pa01 pa02 pa03 pa04 pa05 one or more out of 6 pairs a pair is two ch hit pa00 pa01 pa02 pa03 pa04 pa05 one or more pair in one module not more pa00 pa01 pa02 pa03 pa04 pa05 exactly one pair in one or more modules pa00 pa01 pa02 pa03 pa04 pa05 exactly one pair in one module a ae MC lt MC lt MC lt MC lt p000 po01 p002 po03 p004 po05 one or more out of 6 pairs a pair is one of two ch hit po00 po01 p002 po03 p004 po05 one or more pair in one module not more p000 po01 p002 po03 p004 po05 exactly one pair in one or more modules po000 po01 p002 po03 p004 po05 exactly one pair in one module
13. the new data and Histo to update the displayed spectrum The full spectrum length is equal to 64k channels Use No of bins and Delta E settings to compress the spectrum such that it fits the display Hint use 8000 and 4 to see the full range of data and then adjust these numbers to zoom into the range of interest The number of bins and the delta E variables are kept in memory for each channel individually Be sure to select the channel of interest prior to changing these variables Use the mouse to zoom in on peaks of interest The Fit menu allows you to make Gaussian fits to peaks in the histograms The fit range can be set channel by channel in the Min and Max fields or by placing cursors on the spectrum with the mouse The Fit menu starts a fitting routing for one or all channels The routine does take a constant background term into account though its value is not displayed The fit results that are displayed include the peak position the number of counts in the peak and its relative and absolute full width at half maximum FWHM calculated from the Gaussian fit For best results be sure to extend the fit range to cover some of the constant background The Zoom buttons above the graph can be used as shortcuts to zooming operations with the mouse The Reset Scale button resets the scaling of the MCA to 1 bin Run Statistics The run statistics for all modules and channels are displayed in the All Run Statistics panel
14. to four panels where parameters and acquisition options are entered To get started select Parameter Setup in this menu which will open or bring to front the Parameter Setup panel For most of the actions the Pixie Viewer interacts with one Pixie 4 module at a time The number of that module is displayed in the Main control panel and at the top right corner of the Parameter Setup panel inside the Module control Proceed with the steps below to configure your system 1 At the bottom of the Parameter Setup panel click on the Oscilloscope button The Oscilloscope is a graph that shows the untriggered signal input Click Refresh to update the display The pulses should fall between about 1600 and 15000 on the left axis If no pulses are visible or if they are cut off above 16384 or below 0 click Adjust Offsets to automatically set the DC offset There is a control called Offset on the Oscilloscope which can be used to set the target DC offset for each channel in of the full range If the pulse amplitude is too large to fall in the display range decrease the Gain Since the offsets might drift for example after changes in input count rate it is useful to leave the display open and check the offsets once in a while 2 In the Energy tab of the Parameter Setup Panel input an estimated preamplifier RC decay time for Tau then click on Auto Find Tau to determine the actual Tau value for the current channel of the current modul
15. with a coincident pulse from a BGO shield To accommodate delays between the detector signal and the GATE a rising edge on the GATE input starts a counter of length Gate Window A time Gate Delay after a trigger from the Pixie 4 trigger filter local or distributed the status of the counter is latched If still counting the GATEBIT is high If the counter finished already the GATEBIT is low The GATEBIT is recorded in the list mode data upper 4 bits of the hit pattern word If the required checkbox is set this channel requires the GATEBIT to be low to record event data If the inverted checkbox is set additionally this channel requires the GATEBIT to be high to record event data If the invert edge checkbox is set the counter is started on the falling edge of the GATE input Checking the no pulse checkbox bypassed the window delay logic and the status of the GATE input is directly latched into GATEBIT at the time of the fast trigger The Pixie 4 has no front panel input for GATE signals but they can be passed to the module through the backplane by a neighboring PDM module to the left of the Pixie 4 Alternatively if the uses GFLT input box is checked the GFLT Veto input is used as the source for the GATE signal Statistics Normally if the Gate Statistics checkbox is not checked the gate dead time GDT counter only increments if the channel is live i e run in progress signal in range etc However in some applic
16. words no waveforms 0x102 compressed event data 4 words no waveforms 0x103 compressed event data 2 words no waveforms Note that even in compressed list mode runs 0x101 103 where no waveforms are recorded waveforms are captured for possible pulse shape analysis by the CFD algorithm or user code If no such processing is performed Trace Length should be set to zero to minimize dead time Fast List Mode Fast list mode is no longer supported MCA Mode MCA mode puts all modules into a typical spectrum only acquisition mode in which there are no list mode data required The event data is not stored in the output buffer but only used to calculate the energy for incrementing the spectrum Runs end after the time specified in Run Time counts down to zero Poll Time The polling time indicates the time interval at which the Pixie 4 Viewer checks if the run in the selected modules has ended If so runs are stopped in all modules if they have not stopped already and the 2 3 2014 Pixie 4 Online Help 13 data are read out The polling should be as fast as possible in list mode runs so that the module does not have to wait too long with a full data buffer until Igor notices this and reads out the module However the polling routine itself requires a certain amount of time to perform This time is about 0 03s so a poll time shorter than 0 03s will not lead to faster polling In fact Igor will be so busy with polling that the run time
17. 00 gt multi_req1 multi00 gt multi_req1 multi00 multi_req1 multi00 multi_req1 multi00 multi_req1 multi01 gt multi_req1 multi01 gt multi_req1 multi01 gt multi_req1 1 or more in either not both modules multi01 multi_req1 2 or more in either not both modules 3 or more in either not both modules 1 in either not both modules 2 in either not both modules 3 in either not both modules multi01 multi_req1 A A A A A multi01 multi_req1 Ss a a a aes Se oe YS YS YY YW MC lt pa00 pa01 pa02 pa03 one or more pairs out of 4 pairs a pair is two channels hit MC lt pa00 pa01 pa02 pa03 one or more pair in one module not both MC lt pa00 pa01 pa02 pa03 exactly one pair in one or both modules MC lt pa00 pa01 pa02 pa03 exactly one pair in one not both module MC lt p000 po01 p002 po03 one or more pairs out of 4 pairs a pair at least one of two channels MC lt p000 po01 p002 po03 one or more pair in one module not both MC lt p000 po01 p002 po03 exactly one pair in one or both modules MC lt po00 po01 p002 po03 exactly one pair in one not both module 3 module tests 16 n0300 16 h0301 16 h0302 16 h0303 16 h0304 MC lt MOCO amp IMOC1 amp IMO
18. 2 3 2014 Pixie 4 Online Help 1 PIXIE 4 Online Help Version 2 50 July 2012 XIA LLC 31057 Genstar Road Hayward CA 94544 USA Phone 510 401 5760 Fax 510 401 5761 http www xia com support xia com Disclaimer Information furnished by XIA is believed to be accurate and reliable However XIA assumes no responsibility for its use or for any infringement of patents or other rights of third parties which may result from its use No license is granted by implication or otherwise under the patent rights of XIA XIA reserves the right to change the DGF product its documentation and the supporting software without prior notice 2 3 2014 Pixie 4 Online Help 2 e Getting Help for the Pixie 4 There are several ways to get help for the Pixie 4 You can use IGOR s built in help browser to access the Pixie 4 specific help file by selecting Help gt Help Topics from the top menu bar Choose Pixie4 Help in the popup menu on the left and select the appropriate help topic from the list on the right Each Pixie 4 Run Control Panel also has a Help button which directly displays the help topic for that panel In the help topics click on blue underlined links to jump to cross references Bold blue bracketed text refers to buttons or control fields in the control panels e Getting Started Preparations 1 If you have a remote controller first install the driver software for the controller itself Unless directed otherwi
19. 4 and the PDM control pattern as listed below This decision list is implemented in the PDM s firmware with no claim to cover all cases Please contact XIA to request additional cases or to obtain verilog source code to write custom PDM firmware Events are accepted if MC 1 Logic operators are AND amp XOR OR NOT Operators in front of an array hit a b or a b c d are unitary reductions to a single bit e g amp a c b a AND b AND c Variables are defined as follows multi_all multiplicity of all channels 0 48 in any particular event multi_req multiplicity requirement 1 its value is 1 for PDMcontrol 0 3 1 4 7 2 for 2 5 8 3 for 3 6 9 0 otherwise multi_req2 multiplicity requirement 2 its value is equal to PDMcontrol 0 3 MxCy Hit bit of module x channel y Module 0 is in slot 3 payy pair yy counting from ch 0 and 1 of Module 0 Channels are ANDed poyy pair yy counting from ch 0 and 1 of Module 0 Channels are ORed pxyy pair yy counting from ch 0 and 1 of Module 0 Channels are XORed hitNs an array of all channel N hit bits e g hit0s MO0CO M1C0 M2CO Msum_all number of modules active in event Msum_g1 number of modules in group module 0 module 5 active in event case PDM control pattern test and debug overall multiplicity 16 n0000 MC lt 0 always low 16 n0001 MC lt 1 always high overall multiplicity 16 h001X MC lt multi_all gt mu
20. C2 amp IMOC3 M1CO amp IM1C1 amp IM1C2 amp IM1C3 M2C0 amp M2C1 amp IM2C2 amp M2C3 1 specific channel hit in either module no others MC lt MOCO amp MOC1 amp IMOC2 amp MOC3 M1CO amp M1C1 amp IM1C2 amp IM1C3 M2C0 amp M2C1 amp IM2C2 amp M2C3 2 specific channels hit in either module no others MC lt MOCO amp MOC1 amp MOC2 amp IMOC3 MICO amp M1C1 amp M1C2 amp IM1C3 M2C0 amp M2C1 amp M2C2 amp M2C3 3 specific channels hit in either module no others MC lt MOCO amp MOC1 amp MOC2 amp MOC3 MICO amp M1C1 amp M1C2 amp M1C3 M2CO amp M2C1 amp M2C2 amp M2C3 4 specific channels hit in either module no others MC lt MOCO M1C0 M2C0 Il 1 specific channel hit in either module others don t matter 16 n0305 MC lt MOCO amp MOC1 MICO amp M1C1 M2CO amp M2C1 Il 2 specific channels hit in either module others don t matter 16 n0306 MC lt MOCO amp MOC1 amp MOC2 M1CO amp M1C1 amp M1C2 M2C0 amp M2C1 amp M2C2 3 specific channels hit in either module others don t matter 16 h0311 module 16 h0312 module 16 h0313 module 16 h0314 16 h0315 16 h0316 16 h0330 16 h0331 16 h0332 16 h0333 16 h0334 16 h0335 16 h0336 16 h0337 MC lt multi00 gt multi_req1 multi01 gt multi_req1 multi02 gt multi_req1 1
21. It also shows the time and date of run start and stop and the source where the statistics were last read from The information can be refreshed during a run by clicking the Update button it can be saved to or read from an ifm file with the Files menu The DAQ Fraction is an estimate of the fraction of the lab time a module is taking data As described above Run Time and Live Time measure only the time a module was actively taking data but not the time to setup a run or the time a module is waiting for readout by the host Thus Run Time is always smaller than the elapsed Lab time i e the difference between date time of run start and run stop DAQ Fraction is defined as Run Time Current date time run start date time 100 and thus gives an estimate of the time lost for readout etc After a run is finished the run stop time replaces the current time 2 3 2014 Pixie 4 Online Help 21 Note that Run Time is read from the module while the date time is obtained from the host computer to a precision of 1s DAQ Fraction is therefore not a precise number In list mode runs the time to read out one spill is about 0 030s per module The DAQ Fraction will drop significantly if the time to fill the memory approaches this value To maximize the DAQ Fraction a run in 32 buffer spill mode b make sure the polling time is significantly smaller than the fill time c define only those channels actually used as good and d minimi
22. Viewer will set the DC offset to a percentage of the full ADC range specified in the Offset control Gain and offset can be changed manually with the Gain V V and Offset V controls If pulses begin with a falling edge toggle the invert checkbox The core of the trigger filter FPGA can only trigger on a rising edge If the checkbox is set the FPGA will invert the signal before processing it for triggers You may have to Adjust Offsets again to set the offset properly after inversion The offset calibration must be performed with the preamplifiers connected to the Pixie 4 inputs and with both the preamplifier power and detector HV switched on One should also repeat the offset calibration each time measurement conditions change in any major way e g when the count rate changes greatly All such changes may influence the DC offset value of the preamplifier signal 2 3 2014 Pixie 4 Online Help 17 A Tab control to the right contains additional controls Buttons This tab contains the FFT Display button which opens the FFTDisplay used to analyze the noise spectrum of the acquired trace the Filters button which opens the ADCFilterDisplay used to view the effect of the digital filters applied to the ADC traces and the Caputre button which repeats the acton of the Refresh button until a pulse is detected useful for low count rates Tau This tab contains controls to Manually Fit Decay Time Rates This tab displays the
23. al coincidence test Bits 4 12 15 are used for the channel GATEBIT In order to display traces from an earlier experimental run one needs to change the Data File name by 2 3 2014 Pixie 4 Online Help 20 entering it directly in the Data File control or clicking the Find button To see the response of the energy and trigger filters for the current event click on Digital Filter which opens the Filter Display This window is mainly intended for diagnostic purposes For information how to use the Pixie 4 for more detailed pulse shape analysis please contact XIA Filter Display This graph is used to see the simulated response of the energy and trigger filters in an event You can browse the leading edge trigger filter response and the energy filter response of individual events The latter requires a trace length of at least twice the peaking time plus the gap time to be displayed The trace is shown in red The trigger filter is shown in blue and the energy filter is shown in green Note that only a simple difference filter is displayed for the energy filter without the corrections for baseline and decay of the pulse used in the energy calculations e List Mode Spectrum Pulse height spectra can be reconstructed from list mode data stored on the disk The file shown in the Data File field will be processed and the resulting histograms will be displayed for the selected Pixie 4 module Use Read after changing the data file to process
24. al very small pulses below the threshold or possibly to capture energy estimates on piled up pulses Note that since the timing of the group trigger is not precise with respect to the non triggering pulse the energy reported is only a rough estimate It might help to set the flat top time to a large value to make the capturing of the energy filter less time sensitive Allow energy lt 0 Normally energies computed as negative are set to zero Typically such pulses are close to the noise and the pre trigger sum is larger than the post trigger sum In some applications pulses may be bipolar and it may be useful to preserve the negative value Checking this box will prevent the processing from setting the energy to zero Energy Action Buttons Clicking Optimize Tau opens a panel that allows automatic scanning of all Tau values within the scanning limit specified by the user examining the energy resolution at each Tau and picking the optimal Tau value which gives the best energy resolution Results of this optimization including the Tau value and energy resolution are stored in an output file whose name is specified by the user in the beginning of the run Another file which has the same name as the output file but with a different extension tmp is used to store step by step intermediate results Before starting the optimization all conditions listed on the Auto Optimization of Decay Time panel should be fulfilled first This is to ensu
25. and event data can be displayed on an event by event basis in the List Mode Traces panel The most recently acquired data file will be searched for the event requested in the Trace number field The display will show the traces from the selected module and the associated time stamps energies and PSA values for those channels that reported a hit in this event Also shown are the hit pattern and event timestamp Traces and energies are scaled as 16 bit numbers Note that the ADC traces shown in the Oscilloscope are raw 14 bit numbers i e ADC traces have values divided by 4 compared to list mode traces If 4x longer traces have been requested in the Waveform tab list mode traces are scaled with correct 4 times larger dt but the amplitude is in 16 bit units for all cases In any case waveforms are left aligned with the first sample so the trigger point appears to be shifted for the 4x longer waveforms but traces captured at a later time by local trigger do not appear shifted by that time difference one has to take into account the time stamp difference to obtain the correct alignement of the traces Other displays show the Event times and the Hitpattern The last 4 bits of the hit pattern mark the channels recorded bits 0 3 for channel 0 3 and bits 8 11 mark the channels reporting a hit bits 8 11 for channel 0 3 Bit 5 shows the result of the local coincidence test bit 6 the level of the Status line and bit 7 the result of the glob
26. as the same name as the output file but with a different extension tmp is used to store step by step intermediate results Again before starting the optimization all conditions listed should be fulfilled first This is to ensure that valid MCA spectra will be produced during the optimization and Gauss Fit of energy peaks on the MCA spectra will generate meaningful results The four channels of a Pixie 4 module can be used to 2 3 2014 Pixie 4 Online Help 8 optimize four different Auto Scanning Limits at the same time when the same detector signal is split and input into the four channels This would speed up the scanning of a large range of energy filter rise time and flat top You could change the Auto Scanning Limits of each channel by changing the Channel control on the left upper corner of the Pixie4 Run Control panel At any time the Pixie 4 module used to carry out this optimization is the current module i e the module indicated by the Module control on the left upper corner of the Pixie 4 Run Control panel So if you want to use a different module change the Module number before you set the Auto Scanning Limits for each channel Click on Scan Settings to open the File Series Scan panel This panel allows scanning of filter parameters and Tau in a series of files Waveform The Waveform tab of the Parameter Setup panel sets parameters that control the operation of the waveform capture and pulse shape analysis PSA If
27. ations the GATE VETO signal may be the main condition for taking data Examples include a generator that is periodically on and off and data should only be taken if the generator is on If the on off signal us used as the VETO signal for the Pixie 4 it may be desired to only count the livetime and count rates when the generator is on or off This can be accomplished by checking the Gate Statistics checkbox If checked all time and rate counters except RUN TIME and TOTAL TIME are only active if the GATE or VETO is high blocking events Optionally the condition can be inverted by checking the GDT allow checkbox This means GATE or VETO must be present for the channel to be live In turn GDT is counted independently from whether the module is live or not 2 3 2014 Pixie 4 Online Help 10 Coincidence The Coincidence tab of the Parameter Setup panel sets parameters that control coincidence acquisition within a module For coincidence between modules refer to the ChassisRegisterPanel If not all described controls are visible click on the More button at the bottom of the panel Allowed Hit Pattern In this section you can select the Coincidence Pattern that defines which channels have to contribute to an event to make it acceptable For example you might be only interested in events in which only a single channel was hit or in any event in which more than two channels contributed For each event the Pixie 4 first reads which c
28. bal coincidence test can be applied using a PXI PDM in slot 2 Each module can send its hit pattern to the PXI PDM The module in slot 2 defines which test the PXI PDM should apply see above and the PXI PDM outputs the result of the test on a shared backplane line In addition each module can add the negative result of its local test to the global test essentially vetoing those events that do not pass its local test for a modules This allows one or more master trigger modules to influence acquisition for all modules Limited module coincidence requirements can thus be applied even without a PXI PDM With the checkboxes in the Module Coincidence Setup each module can thus be set to accept events if a only the local coincidence test is passed check local b only the global coincidence test is passed check global c either the local OR the global coincidence test is passed check global and local d the global test AND all relevant local tests pass check global and local adds to global The Coincidence Pattern and Coincidence Window for each module are shown for reference only A further option is Channel 3 Hit contributes to STATUS line which makes this information available in the event hit pattern for all modules Examples 1 To require a local coincidence of channels 0 1 2 3 or both set the coincidence pattern to 0x9008 in the ModuleRegisterPanel and check only the local test box in the Chassis Re
29. between subsequent runs In some cases it may be beneficial to resynchronize the clocks in every new run i e reset the clock to zero for every new data file To do so check the every new run checkbox For Pixie 500 modules the check box 500 MHz Timestamps selects if event and buffer header time stamps are in units of 13 33 ns useful if Pixie 4 and Pixie 500 modules are operated together and events should be matched across modules or in units of 2 ns matching the digitization rate The the smallest increment is 8ns The channel trigger time always is in units of 2 ns For the Pixie 4 all time stamps are always in units of 13 33 ns Start Run After setting all parameters you can start a run to take data During the run the Run Time control shows the remaining time If you select multiple spills for list mode runs the number of spills will also count down during the run For list mode runs when the first module reaching the preset maximum number of events stops its run it will also stop the runs in all other modules if Module Synchronization is enabled Then the data buffer of each Pixie 4 module will be read out and saved into a file If more than one spill is requested the run will resume in all modules When the Run Time control counts down to 0 the Pixie 4 Viewer will issue a run stop command to stop the run in all modules followed by readout of data to file Stop Run If you want to stop a run before it finishes by its
30. buffers counts as one spill The total number of events will be 16 times the Events Buffer times the Number of Spills The modules continue to take data until the number of spills is reached and the host stops the acquisition External memory readout is not supported for Rev B modules Synchronization The first check box asks if all runs should Simultaneously start and stop in all modules In almost all multi module systems this will be the case and the box should be checked Synchronization signals are distributed over a PXI backplane line If a Pixie 4 module is present in the crate but not part of the current data acquisition setup it might inhibit the synchronization setup For setups with more than 7 modules in chassis with PCI bridges make sure the Trigger share mode in 2 3 2014 Pixie 4 Online Help 15 the ChassisRegisterPanel is set to 2 for all module except the left most module which should be set to 3 There must be no gaps between the modules in this case If you also want all timers in all modules to be reset to zero with the start of the next data acquisition run click the box Synchronize clocks For this feature to be useful all Pixie 4 modules should be operating from the same master clock as described in the user s manual Normally once clocks are synchronized they will stay synchronized until modules are power cycled Therefore the checkbox is cleared at the end of the run preserving time correlation
31. but may take a long time for large files If disabled you have to manually load the file in the List Mode Traces graph before viewing traces and or energies Delay runstart will cause Igor to wait in a loop until the current Windows time matches the date and time entered in the corresponding field Force run stop will force the run to end when the current Windows time matches the date and time entered in the corresponding field Both functions are based on a text string comparison and thus require the date and time to be entered in exactly the right format To assist finding this format clicking on the Date Time button will print the current date and time in the Igor history window To abort a run start delay click on the Abort button in the bottom left corner of the Igor window then click Stop Run e Oscilloscope Calibrate gt Oscilloscope The Oscilloscope shows 8192 untriggered ADC samples from the input for each channel The time between samples can be set using the dT variable The display is updated through its Refresh button Any DC offset of the preamplifier signal has to be compensated for in order to bring the DC coupled input into the ADC range The exact DC value has no bearing on the acquired spectrum and its origin which is always at zero The DC adjustment is used only to ensure that the signals to be measured fall comfortably into the ADC range When clicking the Adjust Offsets button the Pixie 4
32. cations are specified as complete not relative search paths the DSP Path for the DSP code and the FPGA Path for the trigger filter FPGA configuration Use a colon as the separator between drive name directory and subdirectories Do not use backslashes For example use D XIA data rather than D XIA data Full path and file name should be limited to 80 characters e MCA Spectrum The MCA Spectrum displays the histograms accumulated in the Pixie 4 modules The channels to be displayed can be selected with checkboxes within the parameter result table Gray fields indicate input parameters purple fields indicate results The Sum checkbox adds or removes the clover addback 2 3 2014 Pixie 4 Online Help 19 spectrum The Fit menu allows you to make Gaussian fits to peaks in the histograms The fit range can be set by the cursors the Min and Max fields in the table or by specifying a percentage range around the tallest or highest energy peak The Fit menu starts a fitting routine for one or all channels The routine takes into account a constant background term though its result is not displayed Results that are displayed include the peak position the number of counts in the peak and the relative and absolute full width at half max FWHM For best results include some of the background in the fit To calibrate the energy scale you can enter a scaling factor keV bin in the table as well This simply changes the label
33. dentify the modules as Custom OEM PCI 9054 Boards without the PLX 8 Find Pixie4 pxp in the installed folder and double click it to open the Pixie 4 Viewer Initial Startup When the Pixie Viewer has been loaded the Pixie Start Up Panel should be prominently displayed in the middle of the desktop It will prompt you to do the following Select PXI chassis type First select the PXI chassis you are using Currently supported are standard 4 5 6 or 8 slot chassis the National Instruments 14 slot or 18 slot chassis with 3 PCI bus segments and the 14 slot 6U chassis designed for Pixie 16 modules by XIA The National Instruments 14 slot chassis has the same PCI bus configuration as the 18 slot chassis only fewer slots 2 3 2014 Pixie 4 Online Help 3 Specify the Pixie 4 modules Next select the number of Pixie 4 modules in the system Then specify the PXI slot number in which each module resides Finally click Start Up System If you want to try the software without a chassis or modules attached click on Offline Analysis In the IGOR history window a message will show if the modules have been initialized successfully You will now see the Main control panel that links to all other control panels Its controls are organized in three groups Setup Run Control and Results In the Setup group the Start System button opens the Pixie Start Up Panel in case you need to reboot the modules The Open Panels popup menu leads
34. e Repeat this for other channels if necessary The Tau finder works best for a Tau value from 20 us to 200 us at moderate count rates 3 At the bottom of the Parameter Setup Panel click on save to save the system parameters found so far You can save the settings into either an existing settings file or a new file 4 Click on the Run Control tab set Run type to 0x301 MCA Mode Poll time to 1 second and Run time to 30 seconds or so then click Start Run After the run is complete go to the Main panel and select MCA spectrum from the Open Panels popup menu in the Results group The MCA Spectrum shows the MCA histograms for all four channels You can deselect other channels while working on only one channel After defining a range in the spectrum with the cursors and setting the fit option to fit peaks between cursors you can apply a Gauss fit to the spectrum by selecting the channels to be fit in the Fit popup menu You can also enter the fit limits using the Min and Max fields or by specifying a range around the tallest peak or the peak with the highest energy To scale the spectrum in keV enter the appropriate ratio in the field keV bin If you are not getting a nice looking spectrum you may need to adjust some settings such as filter rise time and flat top etc Refer to the User s Manual for details Main Panel The Main control panel links to all other control panels At the top of the panel is a control to
35. ed as described above If the Pause box is checked triggers are ignored for 400ns after a first pulse This may be useful in systems where the detector outputs a signal with ringing or overshoots which would cause the Pixie 4 to trigger twice on the same pulse and thus reject it as piled up This effect is usually more pronounced in larger pulses and thus causes a loss of counts at the high end of the spectrum The computed energy is likely to be correct since the ringing is not a second pulse with random energy However this option will make the rejection of real pileup less effective If the Ignore out of range box is checked events are accepted even if the signal goes out of range meaning the detector output is beyond the range of the ADC input after gain adjustment Run Control The Run Control tab of the Parameter Setup panel sets parameters that control the data acquisition If not all described controls are visible click on the More button at the bottom of the panel Run Control Grou This section sets run type run time and polling time Run Type This popup menu is used to set the run type to one of the following modes List Mode List mode is the general data acquisition run Waveforms energies and time stamps are collected on an event by event basis The data is stored in various formats see section 3 6 of the user manual for details 0x100 full event data 9 words plus waveforms 0x101 full event data 9
36. ed to process an event and thus reduce the maximum count rate 2 Pulses occurring during the readout of data after the end of the coincidence window are lost The readout may take several microseconds longer if waveforms are to be recorded 3 The cut off at the end of the coincidence window is precise to within 13 3ns 4 The timeout to a channel s contribution to the hit pattern is adjusted to be 400ns plus the Channel Delay Clover Addback To support 4 fold clover detectors there is a further option to sum energies from individual channels in events with more than one hit and bin them into an addback spectrum This function is enabled with the checkbox Sum channel energies for addback MCA The Pixie 4 module will thus generate 4 channel MCA and one addback MCA at the same time If clover addback is selected there is the further option to omit those events with more than one active channel from the individual channel This clover addback is supported for the accumulation of spectra in MCA mode and in list mode but the list mode data does not contain the sum energy only the channel energies Advanced The Advanced tab of the Parameter Setup panel sets advanced parameters No controls are visible unless the More button at the bottom of the panel is clicked Histogram Control This section shows the parameters controlling the operation of the MCA increment in Pixie 4 memory Energy values are calculated to 16 bit fixed poin
37. elf you can click on this button to manually stop it This will end runs in all modules and read out and save the data Data Record Options This panel gives you several options for automating tasks after or during a run Most are checked by default to ensure all data are saved for each data run Auto increment run number will increase the run number in the file name of the data files to avoid overwriting of files In addition if this option is checked Igor will test at the beginning of a run if the output file already exists testing the bin file for list mode runs and the mca file for MCA runs If the file exists Igor will increment the run number and try again after 20 tries it will add _new to the base file name and continue This feature is intended to avoid overwriting previous files when Igor only remembers a run number from an earlier run for example after a PC crash Auto store spectrum will store the spectrum data automatically after a run as a binary mca file Auto store settings will store the run parameters automatically after a run in binary format same as settings file Run statistics can also be extracted from this file Auto process list mode data will extract the energies and timestamps from the binary data and 2 3 2014 Pixie 4 Online Help 16 save them in a dat file in ACSII format This may take a very long time for large data sets Auto store statistics will store the run sta
38. er Respond to group triggers only This checkbox controls if a channel uses its own trigger or instead the distributed group trigger for the acquisition of waveforms timestamps and optionally energies When not checked only the triggers generated in this particular channel are used When checked the distributed triggers from other channels or modules are used also may include this channel if enabled Triggers are always distributed within a module Any channel with trigger enabled will issue a trigger for distribution and any channel set to group trigger will respond to the distributed trigger including those issued by itself The controls in the ChassisRegisterPanel determine how trigger signals are distributed between modules Good channel Only channels flagged as good will be read out This setting has no bearing on the channel s capability to issue a trigger There can be a triggering channel whose data are discarded Channels not marked as good will not be included in the automatic offset adjustment or the computation of the minimum required coincidence window Read always Check this box if you want a good channel to be read out even if it did not report a hit If operated in group trigger mode you will always get a valid waveform This way you can collect waveforms not biased by trigger requirements If the signal on the channel crossed the trigger threshold even if not trigger enabled you also get a valid energy and
39. est pileup rejection performance The trigger Threshold corresponds to of the pulse height in ADC steps e g with a threshold of 20 triggers are issued for pulses above 80 ADC steps as shown in the Oscilloscope This relation is true if the trigger filter rise time is large compared to the pulse rise time and small compared to the pulse decay time A pulse shape not meeting these conditions has the effect of raising the effective threshold For very slow rising pulses increase the trigger filter Flat Top as much as possible The threshold value is scaled with the trigger filter rise time therefore it is not limited to integer numbers The threshold should be set just above the noise level of the signal For a modeled behavior of the trigger you can open the Filter Display from the List Mode Traces graph or the ADCFilterDisplay from the Oscilloscope that show trigger filter and threshold computed from acquired waveforms using the current settings Setting the trigger Threshold to zero switches off the trigger logic The Enable trigger checkbox only disables triggers being sent to the DSP for event processing and to other channels modules for synchronous waveform capture Threshold 0 switches off local trigger generation so e g the input count rate becomes zero Trigger Options Trigger options include checkboxes to control the following Enable trigger You can switch on or off any channel s ability to contribute to the trigg
40. gister Panel 2 To require coincidence of channels 0 and 1 in Module 0 and no other channel module matters in the ModuleRegisterPanel set the coincidence pattern in Module 0 to 0x8888 and in all other modules to OxFFFF In the Chassis Register Panel check the global test box for all modules and the local adds to global box for module 0 No PXI PDM is required 3 To require at least 3 channels to be active in all modules use a PDM module in slot 2 and set the PDM control pattern to 0x0013 for the module in slot 3 Make sure the Module writes control pattern box is checked for this module and the Send local hit pattern to PDM box is checked for all modules Then check the global test box for all modules
41. hannels contributed before reading any further data This Hit Pattern is a 4 bit number e g 0001 if only channel O contributed or 1111 if all channels contributed By setting the checkboxes you can require that an event must match one of the selected hit patterns to be accepted for further processing Any or all hit patterns can be selected if none is selected no events will be accepted if all are selected any event will be selected The hit pattern 0000 can be useful when sharing triggers between modules Traces etc will be recorded in the module for any channel marked as Read Always in the Trigger tab even if there is no hit in the module itself Setting the checkboxes will automatically modify the 16bit coincidence pattern shown above the checkboxes where it can also be edited directly type Ox to enter a hex number An example shall illustrate this feature Assume a single module connected to 4 detectors which observe a Na 22 source emitting back to back 511keV gamma rays from positron annihilation Channels 0 and 1 are connected to one pair of back to back detectors and channels 2 and 3 are connected to a second pair of back to back detectors You are interested only in gammas from positron annihilation Thus a coincidence in channel O and 1 or a coincidence in channel 2 and 3 is required If all 4 channels were in coincidence that would be fine too So the acceptable hit patterns would be 0011 1100 and 1111 where t
42. he right most digit indicates channel O and the left most is for channel 3 To achieve the desired behavior you have to select the three acceptable hit patterns by checking the appropriate boxes and deselect all other hit patterns by not checking their boxes Note the difference between hit and trigger A hit occurs if a pulse goes over threshold and passes pileup inspection Hits can not be disabled A trigger means there is a hit plus a request for event processing is sent to the module s DSP unit Triggers can be disabled on a channel by channel basis in the Trigger tab Channels will be recorded if they have a hit or their Read always checkbox is set but only hit channels will have valid energy and timing information Coincidence Window The first channel passing pileup inspection starts the coincidence window At the end of the coincidence window the hit pattern is latched from all channels and compared to the acceptable hit patterns If other channels registered a hit during that time they will be included in a common event All channels contribute to the hit pattern whether trigger enabled of not However a channel s contribution to the hit pattern is cleared after a certain delay default 400ns This is to ensure hits don t linger for channels that are not read out The minimum coincidence window is 27ns This window can be increased by entering a number in the Window width control field to accommodate larger dela
43. is issued the specified delay thereafter As the triggers are sent to the backplane the external triggers appear as if an additional module with a pileup inspection time energy filter rise time plus flat top equal to the validation delay had seen a pulse Sharing triggers over the backplane must be enabled even for the module connecting to the external signal PDM control For making coincidence decisions between modules it is recommended to use XIA s logic and preamp power module the PXI PDM It is meant to reside in slot 2 The PXI PDM has no PCI interface and thus is programmed by a Pixie 4 module in the neighboring slot To enable a module to program the PXI PDM the checkbox Module programs PDM to immediate left has to be set The Pixie 4 module then sends the PDM control pattern to the PDM The PXI PDM receives the Pixie 4 s hit pattern through the PXI Star Trigger lines A module can be set to not send out its hit pattern by unchecking the box Send local hit pattern to PDM in slot 2 The PDM assumes a default 0000 Note that due to the architecture of the PXI Star Trigger a module in slot 2 must not send signals on this backplane pin Therefore for a module in slot 2 this checkbox is automatically cleared The module should not be in slot 2 in the first place because the PDM has to be there to receive the hit patterns The coincidence decision in the PDM is determined from the full 48bit hit pattern of the modules in slots 3 1
44. l modules and if enabled in the Gate tab of the Parameter Setup panel a channel only records events where the GFLT signal is present If the Use front panel for GFLT input checkbox is set the current module will internally connect the front panel input labeled DSP OUT to drive the GFLT backplane line Only one device may issue the signal to the backplane If the checkbox is set for one module the function will automatically be disabled for all other modules However it is the user s responsibility to ensure that no other device in the PXI chassis issues signals on this line The Fron panel input signal must be a LVTTL signal i e 0 OV 1 3 3V A second option for the MMCX front panel input is to configure it to contribute to the STATUS line on the backplane This is a wire OR line connected to all modules in a backplane segment If the MMCX input is high the module will pull down the wire OR line this constitutes a logic 1 for this line The state of the STATUS line can be recorded during event processing see below 2 3 2014 Pixie 4 Online Help 23 External Trigger External signals can also be connected to the Pixie 4 front panel input The field Validation delay for external trigger controls generation of fast and event triggers If the value is zero no triggers are generated If the value is nonzero a fast trigger is issued to the backplane immediately after detection of a rising edge on the front panel and an event trigger
45. lti_req2 multi_req2 defined above X 1 F 16 h002X MC lt multi_all multi_req2 X 1 F 2 3 2014 Pixie 4 Online Help single module tests can actually be done in P4 with local contributes to global option 16 h0100 MC lt MOCO amp IM0C1 amp MOC2 amp IMOC3 1 specific channel hit no others 16 n0101 MC lt MOCO amp MOC1 amp M0C2 amp MOC3 2 specific channels hit no others 16 h0102 MC lt MOCO amp MOC1 amp MOC2 amp MOC3 3 specific channels hit no others 16 h0103 MC lt MOCO amp MOC1 amp MOC2 amp MOC3 4 specific channels hit 16 h0104 MC lt MOCO 16 h0105 MC lt MOCO amp M0C1 16 h0106 MC lt MOCO amp MOC1 amp MOC2 i es a 16 h0111 MC lt multi00 gt multi_req 1 or more 16 h0112 MC lt multi00 gt multi_req 2 or more 16 h0113 MC lt multi00 gt multi_req 3 or more 16 n0114 MC lt multi00 multi_req M1 16 h0115 MC lt multi00 multi_req M2 16 h0116 MC lt multi00 multi_req 3 2 module tests 16 h0200 MC lt MOCO amp MOC1 amp MOC2 amp IMOC3 M1C0 amp M1C1 amp IM1C2 amp M1C3 Il 1 specific channel hit in either module no others 16 h0201 MC lt MOCO amp MOC1 amp MOC2 amp IMOC3 M1CO amp M1C1 amp IM1C2 amp M1C3 Il 2 specific channels hit in either module no others 16 h0202 MC
46. on the x axis The Sum menu gives you three options of summing the spectrum You can either sum the range defined by the Min and Max fields without any corrections sum the range and subtract the background or sum the entire MCA Summing is performed on all four channels at the same time The calculated Sum is displayed in the Peak Area field and the bin with the largest number of counts within the sum range is displayed in the Peak field The Files popup menu allows to store individual spectra and read back stored spectra from disk There are three operations Save MCA to Igor text file will save the current MCA 4 channels as a scaled wave with some added comments in a text file This can be useful to import data into other applications Read MCA to Igor text file will read back a Igor text file saved as above Extract MCA from binary file will read MCA data for the current module from a binary file such as the mca file automatically saved at the end of the run The file is assumed to be in 32bit unsigned integer format You can Update the MCA during a run at any time The MCA source field displays where the MCA was last read from e g from the module s memory or a specific file The Zoom buttons above the graph can be used as shortcuts to zooming operations with the mouse The Reset Scale button resets the scaling of the MCA to 1 bin e List Mode Traces After a list mode run has finished the acquired waveforms
47. ots where backplane lines do not support a wire OR across PCI segment boundaries A module in mode 2 receives triggers from the right neighbor builds an OR with its own triggers and sends them to the left neighbor The leftmost module thus receives a daisy chain OR of triggers from all modules and should be set to mode 3 to put these distributed triggers on shared backplane lines PXI_TRIGO PXI_TRIG1 All modules in mode 2 or 3 respond to triggers on these lines i e at the same time Note that the backplane has to be configured to drive PXI_TRIGO and PXI_TRIG1 from the leftmost segment to the other segments In the XIA 18 slot chassis this drive direction is hardwired For National Instrument chassis use the NI PXI explorer to configure the chassis backplane Notes Since other backplane lines are used for other Pixie 4 functions e g PXI_TRIG3 for run synchronization it is generally a good idea to configure the backplane to drive all PXI_TRIGx lines from the leftmost segment to the other segments Also for proper functioning of the run synchronization use mode 2 and 3 in systems with more than 7 Pixie 4 modules even if not sharing triggers Rev B modules are always connected to the backplane equiv mode 1 Front Panel Input Settings One option to connect an external GFLT Veto signal to the Pixie 4 system is to use the MMCxX front panel connector on a Pixie 4 module The GFLT signal is distributed via the PXI backplane to al
48. owing areas Trigger Energy Waveform Gate Coincidence Advanced Run Control It also has several buttons on the bottom of the panel Start System can be used to re initialize the modules Oscilloscope opens the Oscilloscope graph Copy opens the CopyPanel to copy settings between channels modules Extract opens the ExtractPanel to extract settings from file Load loads settings from file Save saves settings to file More will show additional controls on the control panel Help will open this help file at the entry corresponding to the currently active tab About will show software and hardware version information e Trigger The Trigger tab of the Parameter Setup panel sets parameters that control the operation of the trigger filter If not all described controls are visible click on the More button at the bottom of the panel 2 3 2014 Pixie 4 Online Help 5 Trigger Filter In the Filter group you can set the Rise Time and Flat Top for the trigger filter of each channel The units of time are us For a detailed description of filter operation please refer to the User s Manual The trigger filter is always operated at the full ADC sampling rate Its rise time can be varied between 27ns and 840ns Its flat top is valid between Ons and 813ns The trigger filter will most often use a flat top comparable with the average signal rise time In applications with very short rise times a flat top of zero will give the b
49. r not both modules others don t matter 16 h020C MC lt MOCO amp M0C1 4 M1C0 amp M1C1 Il 2 specific channels hit in either not both modules others don t matter 16 h020D MC lt MOCO amp M0C1 amp M0C2 4 M1C0 amp M1C1 amp M1C2 3 specific channels hit in either not both modules others don t matter 16 h0211 MC lt multi00 gt multi_req 16 h0212 MC lt multi00 gt multi_req 16 h0213 MC lt multi00 gt multi_req multi01 gt multi_req1 i 16 h0214 MC lt multi00 multi_req1 multi01 gt multi_req multi01 gt multi_req multi01 multi_req1 multi01 multi_req multi01 multi_req 16 n0215 MC lt multi00 multi_req1 16 h0216 MC lt multi00 multi_req YS YS YY WH fea sean eae ree ON Il 1 specific channel hit others don t matter Il 2 specific channels hit others don t matter 3 specific channels hit others don t matter 1 or more in either module 2 or more in either module 3 or more in either module 1 each in either module 2 each in either module 3 each in either module 24 2 3 2014 160221 16 h0222 16 h0223 16 h0224 16 h0225 16 h0226 16 h0230 16 h0231 16 h0232 16 h0233 16 h0234 hit 16 h0235 16 h0236 16 h0237 Pixie 4 Online Help 25 MC lt MC lt MC lt MC lt MC lt MC lt multi00 gt multi_req1 multi
50. re modules in first group OR at least 3 modules overall II ARSA tests MO gamma pairs M1 M2 beta pairs 16 n1100 MC lt pa00 pa01 amp p002 p003 p004 p005 IL only one pair 2 hits from MO AND exactly one pair gt 0 hits from M1 M2 16 h1101 MC lt pa00 pa01 p002 p003 p004 p005 Il at least one pair 2 hits from MO OR at least one pair gt 0 hits from M1 M2 16 h1102 MC lt pa00 pa01 p002 p003 p004 p005 IL only one pair 2 hits from MO OR at least one pair gt 0 hits from M1 M2 16 n1103 MC lt pa00 pad IL only one pair 2 hits from MO rest don t care 2 3 2014 Pixie 4 Online Help 27 16 n1104 MC lt pa00 pa01 at least one pair 2 hits from MO rest don t care 1611105 MC lt pa00 amp p001 po00 amp pa01 amp p002 p003 p004 p005 Il exactly one pair 2 0 or 0 2 hits from MO AND exactly one pair gt 0 hits from M1 M2 16 h1106 MC lt pa00 amp p001 p000 amp pa01 p002 p003 p004 p005 Il exactly one pair 2 0 or 0 2 hits from MO OR at least one pair gt 0 hits from M1 M2 default MC lt 1 Module Coincidence Setup Each module always tests the Hit Pattern of contributing channels against the user defined Coincidence Pattern set in the Coincidence tab of the Parameter Setup panel before recording and processing an event This is called the local coincidence test A glo
51. re that valid MCA spectra will be produced during the optimization and Gauss Fit of energy peaks on the MCA spectra will generate meaningful results The four channels of a Pixie 4 module can be used to optimize four different Decay Time Limits at the same time when the same detector signal is split and input into the four channels This would speed up the scanning of a large range of Tau values You could change the Decay Time Limits of each channel by changing the Channel control on the left upper corner of the Pixie 4 Run Control panel At any time the Pixie 4 module used to carry out this optimization is the current module i e the module indicated by the Module control on the left upper corner of the Pixie 4 Run Control panel So if you want to use a different module change the Module number before you set the Decay Time Limits for each channel Click on Optimize Filter to open the Auto Optimization of Energy Filter panel An optimization of energy filter settings is carried out by scanning all possible combinations of energy filter rise and flat top within their respective limits specified by the user examining the energy resolution at each combination and picking the optimal combination which gives the best energy resolution Results of this optimization including energy filter rise time flat top and energy resolution are stored in an output file whose name is specified by the user in the beginning of the run Another file which h
52. ription of filter operation please refer to the User s Manual There are several filter Filter Ranges for the energy filter with a granularity of 0 027 us for filter range 1 1 bit decimation 0 053us for filter range 2 2 bit decimation and so on Employing a trapezoidal filter avoids the kind of ballistic deficit that occurs when a finite rise time signal is used in conjunction with a Gaussian shaper The energy filter flat top time should thus be a little larger than the longest rise time expected The output of the energy filter is sampled one decimated clock cycle before the end of the flat top plus the signal arrival may jitter by up to one decimated clock cycle with respect to the decimated clock You should therefore make the flat top two notches longer than the signal rise time The sum of energy filter rise time and flat top cannot exceed 127 decimated clock periods If you type in arise time or flat top value that violates this limit the Pixie Viewer will adjust it accordingly Energy Computation To compute the energy from the filter sums the DSP needs to know the decay time Tau of the preamplifier To set and measure the decay time enter an estimated value then click on the Auto Find Tau button You can also enter a known good value directly in the control The RC calibration needs to be performed only once for a given preamplifier The result is then stored in the parameter database and can be saved in the settings file b
53. rt of the first run all previous run history is cleared e g MCA memory and run and live time information The next nine sub runs are started with a Resume Run command without interaction with the user which leaves previous run information intact Run times and live times and spectra in MCA memory are thus incremented from all 10 spills and the list mode data from all 10 spills is appended to the same file Even if set to zero there will be at least one spill List mode runs end when the Number of Spills is reached or the Run Time is down to zero whichever comes first Spill Timeout This variable sets the timeout for each individual spill During a run it counts down the remaining time If it reaches zero the current spill is ended by the host and a new spill starts Events Buffer List mode data is first accumulated in a buffer in internal DSP memory This variable indicates the preset number of list mode events the Pixie 4 module will store in its buffer for each run The number is calculated automatically if you change the run type The automatically computed value Events Buffer MAXEVENTS is the maximum safe number of events That is given the maximum length of an event all good channels contributing in any case at least MAXEVENTS events will fit in the output buffer MAXEVENTS can be decreased by the user if desired MAXEVENTS can be set to zero to disable the halting at a preset number This makes the acquisition
54. s are visible click on the More button at the bottom of the panel See also the user manual for a detailed description of the Gate and Veto operation GFLT Veto We define Veto as a signal distributed to all modules and channels but each channel may be individually enabled to require or ignore this signal The signal is distributed over the backplane the front panel MMCX connector DSP OUT on the Pixie 4 can be used to input an external signal to the backplane if the module is enabled to do so in the ChassisRegisterPanel Veto is active during the validation of a pulse after pileup inspection an energy filter rise time plus flat top after the rising edge With suitable external logic the decision to veto a pulse can be made from information obtained at the rising edge of the pulse e g multiplicity from several channels and therefore this function is also called Global First Level Trigger GFLT If the required checkbox is set this channel requires the GFLT Veto signal to be present to record event data Present here means the Veto voltage has to be OV on the backplane line or the Pixie 4 front panel input If the inverted checkbox is set the polarity of the GFLT Veto signal is inverted i e the channel requires the Veto backplane line to be absent 3 3V to record events Gate We define GATE as a dedicated signal for each individual channel It is active near the rising edge of the pulse e g to suppress a detector pulse
55. se by the manufacturer of the controller this can be done with or without the controller and Pixie 4 modules installed in the host computer and or chassis If the modules are installed ignore attempts by Windows to install drivers for the modules until step 7 NI controllers come with a multi CD package called Device Driver Reference CD For simplicity it is recommended to install the software on these CDs in the default configuration 2 Unless already installed power down the host computer install the controller in both the host computer and chassis and power up the system again chassis first 3 Windows will detect new hardware the controller and should find the drivers automatically Verify in Window s device manager that the controller is properly installed and has no resource conflicts 4 Install Igor Pro 5 Install the Pixie 4 software provided by XIA 6 Unless already installed power down the host computer install the Pixie 4 modules in the chassis and power up the system again chassis first 7 Windows will detect new hardware the Pixie 4 modules and should find the drivers automatically If not direct it to the drivers directory in the Pixie 4 software distribution installed in step 5 Verify in Window s device manager that the modules are properly installed as PLX Custom OEM PCI 9054 Boards and have no resource conflicts Currently the driver must be version 5 2 The previously used driver version 4 1 will i
56. select the current Module Its other controls are organized in three groups Setup Run Control and Results 2 3 2014 Pixie 4 Online Help 4 In the Setup group the Start System button opens the Pixie Start Up Panel in case you need to reboot the modules The Open Panels popup menu leads to four panels where parameters and acquisition options are entered Parameter Setup Panel Oscilloscope ChassisRegisterPanel AllFilesPanel In the Run Control group Run type popup menu is used to choose the run type described in more detail under Run Control The Start Run button starts a data acquisition the Stop Run button stops it You can also enter the total Run Time and the Number of Spills to be acquired in list mode runs For more run control options see the Run Control tab of the Parameter Setup Panel In the Results group the Update button refreshes the Event rate and Input Count Rate shown below The Open Panels popup menu leads to five panels and graphs that show the data acquired in more detail MCA Spectrum List Mode Traces List Mode Spectrum Run Statistics File Series e Parameter Setup Panel The Parameter Setup panel is use to set all parameter for one particular module except for those related to the analog gain and offset which are located in the Oscilloscope At the upper right of the panel is a control to select the current Module Using the control tabs you can define parameters in the foll
57. t numbers This would correspond to a 64k spectrum To map the full energy range into the available 32k spectrum one has to combine bins At minimum 2 bins have to be combined into one so the Binning Factor has to be set to 1 combining 2 1 bins Higher binning factors can be useful for low count rate or low resolution applications If you want to see a certain range of the spectrum at higher resolution you can enter a Minimum Energy This will discard all energies below the minimum and start binning the spectrum from the minimum energy Bin 0 Emin To disable the incrementing of MCA histograms uncheck the Enable box Pileup Inspection In this group the pileup inspection can be modified Normally events are not recorded if a pulse is followed by a second pulse in less than the sum of energy filter rise time and energy filter flat top 2 3 2014 Pixie 4 Online Help 12 If the Disable box is checked the pileup inspection is disabled i e all pulses are allowed The energy is only computed once for any number of pulses following each other closer than the above limit energy filter sums are latched with respect to the first pulse The result of the energy computation will contain contributions from both pulses and thus be not equal to the energy in either pulse and likely not equal to their sum energy If the Invert box is checked the pileup inspection is inverted i e only piled up pulses are recorded The energy is comput
58. timestamp A checkbox in the Energy tab allows to get an estimate of the energy even when the signal does not cross the trigger threshold Local Timestamp 2 3 2014 Pixie 4 Online Help 6 Set this checkbox to record individual timestamps for all channels in group trigger mode rather than the identical time stamps based on the last group trigger Normally in acquisitions with shared group triggers all channels record the identical timestamp of the last group trigger for this event Since waveforms are captured based on the group trigger this ensures that within a data record the traces and timestamps are correlated However if no waveforms are recorded there is no time of arrival information of possible delays between channels Setting the checkbox preserves the time difference information See the user manual for details Note that since only trigger enabled channels latch time stamps if the box is checked the recorded timestamp is only valid for trigger enabled channels where the signal crossed the threshold e Energy The Energy tab of the Parameter Setup panel sets parameters that control the operation of the energy filter and the pulse height reconstruction in the DSP If not all described controls are visible click on the More button at the bottom of the panel Energy Filter In the Filter group you can set the Rise Time and Flat Top for the energy filter of each channel The units of time are us For a detailed desc
59. tistics and run start stop date and time automatically after a run in ASCII format in an ifm file In addition you can choose to automatically Update MCA every N seconds during MCA runs or every N spills during List mode runs N can be selected in the variable control field Run statistics will be updated at the same time You can also manually update the MCA spectrum by clicking the Update button in the MCA Spectrum display Further you can choose to automatically store data in New Files every N spills during List mode runs or every N seconds during MCA mode runs N can be selected in the variable control field Run statistics will be updated at the same time This feature can be used to break up output data into several smaller files since it will take some time to save the data N should be set to a rather large value i e at least several hundred spills or several thousand seconds Note that a new run will be started after saving i e all run statistics will be reset MCA spectra will be cleared and clocks resynchronized if the in every run checkbox is set in the Synchronization section in the Run Tab Thus enabling this feature is equivalent to manually starting several individual runs with N spills Do not parse list mode file will disable the automatic parsing of the list mode file after the run to build a list of pointers to individual events This is required for Igor to display events in the List Mode Traces graph
60. vent dead time is a concern the trace length should be set as short as possible In particular if only energies and time stamps are of interest the trace length can be set to zero Note that even in compressed list mode runs 0x101 103 where no waveforms are recorded waveforms are captured for possible pulse shape analysis by the CFD algorithm or user code If no such processing is performed Trace Length should be set to zero to minimize dead time Pulse Shape Analysis PSA Start and PSA End specify the trace range for pulse shape analysis PSA Currently the Pixie 4 supports two types of PSA XIA_PSA and USER_PSA XIA_PSA reports the signal arrival time by measuring the time when the trace reaches a preset percentage level constant fraction of its magnitude The percentage threshold can be set defined in CFD Threshold To reduce processing time the XIA_PSA is only performed when the checkbox Compute CFD time is checked The computed value is the arrival time after the start of the acquired waveform in units of 1 256th of an ADC sampling interval PSA Start and PSA End should be set to include the rising edge of the trace The values also are modified by the he 4x longer traces checkboxes again the factor 4 is implied not shown 2 3 2014 Pixie 4 Online Help 9 Gate The Gate tab of the Parameter Setup panel sets parameters that control the gating of the data acquisition with external signals If not all described control
61. will not count down properly Enabling run options like Update MCA every 5 s will lead to an increased time requirement for the polling routine at that interval Run Time This variable is used to indicate the total run time for MCA runs or the overall timeout limit for list mode runs During a run it counts down the remaining time List mode runs end when the Number of Spills is reached or the Run Time is down to zero whichever comes first This time is tracked by Igor and Windows precision is to within 1 2s Output File You can choose a Base name and a Run number in order to form an output file name The run data will be written to files whose name is composed of both i e base HH xxx The run number is automatically incremented at the end of each run if you select Auto increment run number on the Data Record Options panel but you can change it manually as well Data are stored in files in either the MCA folder if the run is a MCA run or the PulseShape folder if the run is a List Mode run These files have the different extension as described below bin For list mode runs buffer data are stored in a file with name extension bin This is a binary file consisting of 16bit unsigned integers dat For list mode runs a summary of event data is stored in a file with name extension dat This is an ASCII file For long list mode runs with many spills this file can become much larger than the binary file If you
62. y clicking on the Save button A manual fit to find the decay time is possible in the Oscilloscope The Integrator variable controls the event energy reconstruction 0 Normal code 1 Use energy filter gap sum only This is equivalent to simply integrating over the pulse It is useful for scintillator applications where event energies can be derived by setting the energy filter flat top long enough to cover the whole scintillation pulses Tau is ignored in this mode 2 Ignore energy filter gap sum when reconstructing event energy This is useful for step pulses whose amplitude is the difference between the high and low steps 3 5 Same as 1 but the energy is multiplied by a factor 2 4 or 8 respectively This is useful for very fast pulses that do not have a lot of area under the peak and thus will show up only at the very low end of the spectrum 2 3 2014 Pixie 4 Online Help 7 Energy Options Energy options include checkboxes to control the following Estimate energy if not hit If a channel is read out even if it did not report a hit see Read always in the Trigger tab its energy is normally reported as zero since there was no valid local trigger to capture the value of the energy filter However as the energy filter is computed continuously checking this box will capture the filter value based on the last group trigger distributed within the module or over the backplane This might be useful for channels with occasion
63. ys between channels as may be required by the physics of the experiment up to a value of about 0 86ms In some cases it may be desired to delay one channel s contribution to the hit pattern relative to the other channels with the Channel Delay parameter For example one channel may have a much shorter cable delays than the others say by 200ns In the detectors pulses may be created at exactly 2 3 2014 Pixie 4 Online Help 11 the same time but the channel with the shorter cable will always start the coincidence window 200ns before the other channels register their hit To accommodate the delay difference the coincidence window would have to be at least 200ns This may be undesirably large so instead one can set the Channel Delay to 200ns which delays the start of the coincidence window by that channel Another use of Channel Delay is to compensate for the difference in energy filter length Since the pile up inspection is roughly equal to the sum of energy filter rise time and energy filter flat top a channel with shorter filter length will pass pileup inspection sooner and therefore start the coincidence window earlier The software thus calculates the required additional window width to compensate for any such difference If the Adjust for E filter box is checked Channel Delay is automatically set to the required value and can not be changed by the user Notes 1 Any added coincidence window width will increase the time requir
64. ze the amount of waveform captured or run in a compressed list mode to store more events in the same amount of memory For example with 4 channels active in mode 0x103 the memory will hold 744 32 23 808 events so at a count rate of 23kcps the memory will fill in about 1s and be read out in less than 0 1s which results in a DAQ Fraction of more than 91 The History button opens a plot in which the event rate for each module is plotted Current event rates are calculated every time the Update button is clicked or an automatic update is performed if the Track Event rates box is checked In the calculation the current event rate is determined as counts since last update time since last update e File Series Scan The File Series Scan panel is used to set up a series of acquisition runs in which the settings are modified One file is saved for each setting creating a file series that can be processed in the File Series panel A control field Filter Range is repeated from the Energy tab In three groups of controls you can set the start end and step size for varying the energy filter rise time the energy filter flat top and the decay time Tau If the step size is zero that parameter will not be varied Two buttons assist in setting up the initial conditions Set Parameters to Start sets the current values of the energy filter and Tau to the start value defined in the File Series Scan panel If you omit to click

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