- Paul Scherrer Institut
Contents
1. QL 4 SGL SGU 1 2 00 0 00 0 00 65 31 8721 125 522 2 0 00 4 00 4 00 99 45 20 39 425 122 16 SHORT USER MANUAL Calculate the UB matrix with 2 0 0 as primary peak and 0 4 4 as secondary peak SICS makeub 12 UB 2 456 0 530 0 200 0 530 2 456 0 090 0 200 0 090 2 456 Peak QL 4 SGL SGU QH QL 2 00 0 00 0 00 65 31 87 21 1 25 522 2 03 0 00 0 00 2B 0 00 400 400 99 45 2039 4 25 122 0 02 3 95 4 03 The last 3 columns above show the Q values calculated back from the angles Drive to the 2 0 0 peak SICS dr qh 200 SICS pr A4 A3 SGL SGU A4 64 218 A3 87 515 SGL 2 258 SGU 3 217 The value of A4 has changed because the cell constants do not match the values given for the first peak The value of A3 has changed by the same reason and in addition because the the plane given by 2 0 0 and 0 4 4 is now tilted back into in the scattering plane For the latter reason SGU and SGL have changed also SICS DR QH 333 SICS PR A4 A3 SGL SGU A4 82 516 31 215 SGL 2 258 SGU 3 217 Note that the values for SGU and SGU have not changed The will not change as long as we stay in the scattering plane no drives to Q3 and as long as the UB matrix has not changhed SICS REF 3 3 3 Peak QL 4 SGL SGU 3 00 3 00 3 00 82 32 31 25 2 26 3 22 SICS MAKEUB CB UB 2 456 0 530 0 200 0 530 2 456 0 090 0 200 0 090 2 456 Peak QL 4 SGL SGU QH2. 1 1 1 2 2 1 1 1 1 1 1 1 1 2 2 1 1 1 1 1 1 Index 1 1 1 Index Index Index Index Index W Index 1 1 Index 1 1 Index 1 1 Index 2 2 Index 1 1 Index 1 1 Index 1 1 Index 2 43 44
3. QL 1 2 00 0 00 0 00 65 31 87 21 1 25 5 22 2 03 0 00 0 00 2B 0 00 4 00 4 00 99 45 20 39 4 25 1 22 0 02 3 95 4 03 17 SHORT USER MANUAL 3A 3 00 3 00 3 00 82 32 31 25 2 26 3 22 3 00 3 00 3 00 We have calculated a new UB matrix based on the peak 3 3 3 as primary and the 0 4 4 as secondary peak The UB matrix has not changed as we were already exactly at 3 3 3 2 4 2 Out Of Plane Operation This formalism allows to drive out of the scattering plane using the tilt motors of the sample stage Some cryostats cannot stand this Therefore driving out of plane can be switched off and on SICS TASUB OUTOFPLANE This command switches out of plane operation on SICS TASUB OUTOFPLANE 0 This command switches out of plane operation off SICS TASUB OUTOFPLANE lists the current value of the out of plane variable 18 SHORT USER MANUAL 2 5 Scan command The scan syntax is like on TASMAD The general scan command is SICS sc an device lt center gt lt step gt np lt preset gt with the arguments device any driveable variable and lt center gt its center value step any step d immediately followed by the variable name followed by the number of points preset followed by the monitor mn or time ti preset value The presence of 4 argument parts is mandatory but the order of the parts 1s not relevant For every step variable the corresponding center value must be given If no step is given for
4. Exch T 1 506 7 MagBottom 4 236 MagTop 4 3 T T T gt 12h We25 T ae 12h Th 3 5 gt 12h 7 Sample Pow ValvePos 21 Helevel 38 4 N2Level 62 5 Mag Field 5 Curent 7 Flow 3 88 LambdaFlow 986 3 Range Settings Show All live mode X Sea rita MA15 Change Device sample settemperature gt sample control parameters vti set temperature 0 0 Y ITC temperature controller set limit 1000 0 drive timeout 1 0 settling time sec needle valve control C off manual automatic 20 0 auto valve limit tolerance 11 valve setting 25 gt ITC pid control gt lambda controller gt magnetic field control serial connections Input Output History EL Command Input pt The SEA graphical user interface Once the sea user interface appears select the cryostat device in use if not already done automatically e g DISE for the Risoe Displex E MA15 for the 15 T magnet In SICS temperatures are changed by SICS run tt 50 just sets the temperature without waiting control is given back to sics immediately SICS dr tt 50 waits for temperature to be stable Stability criteria and settling time can be changed in sea window Variable name for magnetic field is mf SICS dr mf 5 Changes the magnetic field to 5 T on the magnet in use 36 THE 15 VERTICAL MAGNET MA15 Chapter The Oxfor
5. vertical axis the corresponding motor is called OMM A5 when working in one of the standard triple axis modes All blades of the analyzer may be set to the same angle by the command PARK a where a is the setting angle a flat analyzer is obtained by typing PARK 0 As for the monochromator the d spacing of the reflection at the analyzer must be stated this is done by setting the variable DA 3 354 A for PG 002 1 8 Position Sensitive Detector For counting the neutrons RITA II uses a 30x50 cm position sensitive detector PSD which bins the neutron counts into 128 x 128 pixels see fig 1 The distance from the analyzer axis to the detector face is variable and the maximum value depends on the position of the analyzer The detector is able to swing around in the tank to one side only see fig 2 The corresponding motor name is 2TA A6 Secondary detector p 7 PSD Analyzer 10 SHORT USER MANUAL Chapter Short User Manual System SICS and the most relevant commands needed to control the instrument during n this chapter we will give a brief introduction into the SINQ Instrument Control an experiment Convention for type setting in this manual e lt device gt stands for all drivable variables motors fields temperatures etc e lt value gt stands for a required variable entry lt value gt stands for an optional variable entry entra
6. 13 57 27 68 76 71 76 99 52 Table Al O reflexes at different energies 27 RITA MODES 43 Monochromator curvature Remove the 40 collimator from the analyzer housing Die Energie der einfallenden Neutronen ist nun bestimmt was nun optimiert werden kann ist die Kriimmung des Monochromators CUM SICS uses a macro to calculate the energy dependnet curvature E CUM A A 2 d 4 with A1 0 44 und A2 10 87 1 2 PG 002 81 804 WI un The constants A1 and A2 have to be determined experimentally Mount a Vanadium sample Set A4 to 90 degrees Perform cum scans at different neutron energies SICS dr ef 5 SICS sc cum 26 dcum 1 np 51 mn 1000 SICS dr ef 8 SICS sc cum 26 dcum 1 np 51 mn 1000 RITA 2 Eichung CUM E 14 68 LL Mai 2002 Position Mox Intensity Int Intensity fwhm Gaussian twhm Lorentzian 30 34 0 86 345 2 13575 2765 366 35 Int Intens Exp dBgfdx 11849 335 183 4 2 40 7 1 043 40 708 Moniter 10000 ve X 0 8629 54 400 200 CUM Intensity versus monochromator curvature CUM at 14 68 meV From the energy dependent maxima CUMmax Es one can determine the SICS macro parameters A and 28 RITA MODES 4 4 OMA calibration It has for some time been a problem that the angle between the analyzer rack and the beam motor OMA cannot be properly calibrated This is due to the flexibility of the analyzer in the capa
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8. 3 1 Data Conversion 33 5 3 2 Matlab Routines 33 Sample Environment Control 35 6 1 Sample Environment Automation SEA 35 The Oxford 15T magnet MA15 37 7 1 Regulations and Specifications 37 7 2 Installing MA15 38 7 3 Change to from Omega Motor on Sample Stick 42 Index 43 Chapter The Instrument Source SINQ at the Paul Scherrer Institute in Villgen Switzerland The instrument is being operated in a joint venture between the Paul Scherrer Institute and the RISOE National Laboratory Denmark RITA II is based upon the conventional triple axis idea optimized in several ways Its main components are R ita II is a triple axis spectrometer for cold neutrons at the Swiss Spallation Neutron Supermirror coating m 2 in the neutron beam guide A vertically focusing monochromator Motorized slits Be and BeO filters with built in collimators A flexible 9 bladed analyzer A position sensitive detector PSD A vertically focusing monochromator The multi bladed analyzer combined with the PSD provide flexibility for measurement and opportunities for getting additional efficiency 1 1 Beamline and Guide The neutrons from the Swiss Intense Neutron Source SINQ leave a cold source end enter the guide system RNR13 The primary super mirror m 2 beam guide is 20 m long and has a curvature radius of 2408 m The guide cross section is 12 x 3 cm Neutron fluxes were determin
9. is obtained by SICS ritamode monoim In this mode the different blades scatter on different parts of the PSD and have slightly different q values In order to minimize cross talk between the blades a flexible radial collimator is installed in front of the PSD RITAs Monochromatic Imaging mode Position Sensitive Detector Flexible radial igi j collimator i f i f Analyzer configuration in monochromatic q dispersive mode The collimator blades can be driven by the two motors and re for the left and right half of the collimator respectively Typical values for and rc are given in the table below 25 RITA MODES Chapter RITA II Alignment 4 1 Monochromator e Insert 40 collimator into the beam opening of the monochromator shielding Place a 15 mm slit in front of the monitor which is mounted on the 600 mm X95 profile e Drive monochromator flat no curvature SICS dr cum 0 e Drive A2 2TM to the desired value see Table 1 Scan A1 OMM around its nominal value In order to do this you have to set the counter box threshold to zero and scan by time stable beam required SICS sc omm current_value domm 0 05 np 21 ti 1 find maximum intensity for OMM drive there and redefine OMM by 2TM 2 SICS sp OMM 2TM 2 Energy Wavelength OMM 2TM meV A Monochromator 28 Monochromator 3 63575 4 7434 45 00 90 00 5 0 4 0448 37 08 74 17 8 0 3 1977 28 47 56 94 13 68 2
10. or does not 0 divide by monitor Matlab Det Images filename e g Det _Images home rita2 data 20 10 00 1 rita22010n001258 hfd Graphical User Interface Matlab qad view fs ps fits s gauss 1 2 4 0 20 1 1 1 1 Gaussian fit to s with start parameters 12 4 0 2 0 Amplitude Position width Background 34 SAMPLE ENVIRONMENT CONTROL Chapter Sample Environment Control 6 1 Sample Environment Automation SEA controlling and monitoring sample environment devices such as Lake Shore EA means Sample Environment Automation It is client server software for temperature or Oxford magnet controllers Its main features include e Logging of all relevant variables at 5 sec interval stored for at least one year Control logic not handled by the hardware automatic needle valve control correction for sample heat exchanger difference e Charts for live display and for inspecting the history Graphical user interface for changing control parameters Command interface commands can be used in an instrument batch file or entered directly Instrument Control E SICS Client GUI Diagram showing the client server architecture of SEA and how it is embedded into the instrument control software 35 SAMPLE ENVIRONMENT CONTROL To start a SEA client enter term sea amp on the unix command line or click on the SEA icon on the linux desktop ze Sample T 1 56
11. 4453 21 38 42 76 Tabelle 1 Scattering angles Al OMM and 2TM for specific energies The monochromator is mounted on a goniometer motor name GM Check GM by performing a scan Before doing so insert a vertical bezel in front of the monitor vertical opening 30 mm SICS sc gm current_value dgm 0 1 np 21 mn 1000 26 RITA MODES T T T FWHM 1 139 A GM 1 0876 Goniometer scan at E 4 meV The measured FWHM is 1 14 and maximum Intensity is obtained at GM 1 08 1500 1000 500 4 2 2T and neutron energy Mount the Riso TAS 6 10 sample on the sample table to determine the neutron energy and the zero point of A4 2T Counting rate in auxiliary detector AUX Insert a 40 collimator into the analyzer housing RITA 2 is in 2 axis mode Measure the intensity of a peak with both negative and positive A4 2T Lazy Input for TITLE AL203 CONDIT 2 4571 5 0 75 0 NE CELL 4 76100 12 99100 120 SPCRGP R 3 C ATOM AL 1 0 0 0355 1 0 303 0 0 25 INTENSITY CALCULATION FOR AL203 TRIGONAL STRUCTURE A 4 76100 C 12 99100 WL 2 45710 SCATTERING FACTOR COEFFICIENTS B Al 0 34490 CM 12 B O 0 58030 CM 12 Energy 20 012 20 104 20 006 20 113 20 116 meV d 3 4811 A d 2 5513 A d 2 1652 A d 2 0861 A d 1 6017 Intensity 84 5 569 143 7 693 68 1176 62 3 63575 85 89 5 0 71 04 104 87 8 0 54 68 77 61 95 20 100 07 13 68 41
12. ET MA15 39 Unplug cables here Replace the 4 limit switch plugs by dummy plugs to prevent the ECB system from crashing THE 15 VERTICAL MAGNET MA15 Install the magnet Matching plugs and sockets are marked with the same color Motor Controller for Sample Rotation Current Leads for magnet rna VTI to He pump Helium Recovery Line He pump for Lambda stage for fields above 13 5 40 THE 15 VERTICAL MAGNET MA15 Connect sample temperature cable with the Lakeshore Controller Connect all the other cables cables according to the color scheme RITA2 Serial Connections Lantronix Terminal Server Insts02 psi ch Chan Cable Description 1 service channel reserved 2 PSI motor controller EL734 monochromator motors 3 4 mobile PSI motor controller EL734 omega motor on MAIS sample stick 5 PSI counter box EL737 6 ILakeShore 340 Needle Valve Controller LM Oxford Instruments Level Meter 2 stop bits IPS Oxford Instruments Magnet Power Supply 2 stop bits IGH Oxford Instruments Gas Handling System 2 stop bits Oxford Instruments lambda controller 2 stop bits ITC Oxford Instruments Temperature Controller 2 stop bits LakeShore 370 7 bit odd parity 41 THE 15 VERTICAL MAGNET MA15 The MAIS entrance window is defined by a line marked as WINDOW CENTER LINE Line up this line with the monochromator s
13. PAUL SCHERRER INSTITUTE Laboratory for Neutron Scattering LABORATORY FOR NEUTRON SCATTERING Rita Il Manual Christof Niedermayer and Niels Christensen Laboratory for Neutron Scattering Paul Scherrer Institut CH 5232 Villigen PSI Phone 41 56 310 2086 Fax 41 56 310 2989 christof niedermayer psi ch niels christensen psi ch Table of Contents The Instrument 2 1 1 Beamline and Guide 3 1 2 Monochromator 4 1 3 Beam Monitor 5 1 4 Sample Table 6 1 5 Motorized slits 7 1 6 Filters 7 1 7 Analyzer 8 1 7 1 The analyzer tank 8 1 7 2 The nine bladed analyzer 8 1 8 Position Sensitive Detector 9 Short User Manual 11 2 1 Introduction to SICS 11 2 1 1 RITA 2 Configuration 12 2 2 Starting SICS 13 2 2 1 six 13 2 3 Drive Check and Modify device parameters 14 2 4 UB Matrix and Crystal Alignment 15 2 4 1 Example Session 16 2 4 2 Out Of Plane Operation 18 2 5 Scan command 19 2 6 Other Commands and Procedures 20 2 6 1 Simulation Mode 20 2 6 2 Batch files 20 2 6 3 Counter Box Threshold 21 2 6 4 Monochromator Curvature 22 2 6 5 Scattering Sense 22 Rita Modes 23 3 1 Two axis and three axis modes 23 3 2 Flat mode 23 3 3 Monochromatic point to point focusing mode 24 3 4 Monochromatic imaging mode 25 RITA II Alignment 26 4 1 Monochromator 26 4 2 2T and neutron energy 27 4 3 Monochromator curvature 28 4 4 OMA calibration 29 Data Treatment and Analysis 32 5 1 Data Format 32 5 2 Data Storage 33 5 3 Data Analysis 33 5
14. a center variable a step 0 is used Special cases are the variables QH and Q3 and their corresponding steps DOH and DQ3 which have 4 or 3 values Examples SICS SC A3 40 DA3 0 1 NP 41 MN 1000 orders a scan of A3 around 40 degrees with 20 steps to either side with a step width 0 1 and 1000 counts in the monitor Alternatively the preset value time gives the counting time in seconds SICS sc a3 40 da3 0 1 np41ti 1 Energy scan the following two beeing equivalent SICS SC QH 1000 DQH 0000 01 NP 5 MN 1000 SICS SC QH 1 00 EN 0 DEN 0 01 NP 5 MN 1000 q scan the following two beeing equivalent SICS SC QH 1000 DQH 0 0 01 00 NP 5 MN 1000 SICS SC QH 1 000 DQE 00 01 0 NP 5 MN 1000 The scan uses the value of device and the number of counts window 5 as plotting variables in rita2status One can also scan multiple motors For example a 0 2 0 scan is performed by the following command SICS sc a3 40 2 da3 0 1 a4 73 5 da4 0 2 np 41 mn 1000 19 SHORT USER MANUAL 2 6 Other Commands and Procedures 2 6 1 Simulation Mode For testing batch files or in order to check the movement of the instrument it may be helpful to run SICS in simulation mode You must then connect to a special simulation SICS server Open a new sics client and connect to RITA 2 SIM term sics amp In the simulation server everything is like in the actual SICS server except that no hardware is moved no counts collected and no data file written There
15. ample axis This is most easily done by aligning the 45 mark with the 45 mark on the sample table angle scale or 135 225 315 7 3 Change to from Omega Motor on Sample Stick in home rita2 rita2_sics rita2 tcl change the following line set mal5motor 1 1 for motor on sample stick 0 for normal omega table and then restart sics with the command term monit restart sicsserver If the motor is not running it may be necessary to load the motor parameters with the el734 test program Type term el734 test help for documentation A parameter file can be found under home users tascom PSI mot 4 01 par The serial cable for the omega motor is connected to channel 4 port 3004 on the terminal server Insts02 psi ch 42 INDEX Index A Index Index Index Index 2 2 Index 3 3 Index Index B Index Index Index Index 2 2 C Index Index Index Index 2 2 Index Index Index D Index Index Index Index Index Index Index Index 2 2 Index Index Index G Index Index Index Index Index Index Index 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 9 1 1 1 1 1 1 1 1 1 1 1 1 1 2 2 Index Index Index Index 1 1 1 1 Index 1 1 Index K Index 1 L Index 1 1 2 2 1
16. bility of turning the analyzer blades As the blades turn around the same axes as OMA certainly blade 5 only one of these angles can be calibrated The analyzer consists of 7 blades numbered 2 to 8 controlled by the motors ca2 to ca8 The point to point focusing mode ritamode focus was designed to monochromatically focus the beams reflected from the different blades of the analyzer to the same point on the detector Because of the asymmetry of the analyzer rack relative to the incoming neutron beam and the asymmetry of the detector to the analyzer the beams from the different blades will actually intersect the detector at slightly different positions This is seen in figure 1 a calculated theoretically assuming 5 meV neutrons and perfect alignment of all angles ca4 ca7 ca8 Pu m es 5 Di pa 0 1 2 3 Position on PSD pix a Perfect alignment of OMA ca4 3 7 8 DM T E FE T T T T I 0 1 2 3 Position on PSD pix b OMA 2 below perfect alignment The calculated intersection points on the PSD in the point to point focusing mode The beam from the central blade ca5 is defined to intersect the detector at 0 This corresponds to pixel 64 on the PSD The exact position of the intersection can be controlled with the motor 2TA Actually this can be used to calibrate 2TA In the following it is only the relative position of the intersections that is
17. can files The translations of the monochromator are TUM in arbitrary units and TLM in arbitrary units The monochromator goniometer is GM The monochromator is rotated by the motor OMM or A1 all angles in units of degrees The corresponding scattering angle is 2TM or A2 There is an encoder on this angle The monochromator d spacing is set by the variable DM 3 354 A for PG 002 1 3 Monitor RITA II is equipped with beam monitor with an opening of 80 40 mm This is normally located on a holder on the first motorized slit right at the exit of the monochromator shielding The monitor counts are stored in the SICS variable MON and the corresponding rate meters are called RmS RmM and RmF for slow medium and fast response times respectively The units are counts sec Normal monitor count rates are given in the following table Configuration Seconds 1000 Monitor Focussing mono SINQ current 1020 nA 1500 7 1 a e 750 AE gen M _ fm on d i E n mi a 10005 TM 440 amp f a F 5 4 2 2 VEN 430 d E m d EOM ION 500 3 450 B amp p di enin r 110 0 oe a 1 LL 1 2 4 6 8 10 12 14 16 18 E meV Measuting time for 10000 Monitor 1 4 Sample Table The ce
18. ct peak2 is used only for determining the scattering plane SICS makeubfromcell Calculate and activate a UB which has been derived from the cell constants alone This is useful to get a4 when no reflection has yet been found to calculate a proper UB 15 SHORT USER MANUAL SICS makeauxub gh qk ql Calculate a UB matrix from the first reflection and an auxiliary second reflection specified through the miller indices qh qk ql The auxiliary reflection will have the same angles as the first reflection except a3 and a4 will be adjusted to match the requirements from the crystals geometry SICS listub List the UB matrix the cell constants and all stored reflections 2 4 1 Example Session First enter the cell parameters SICS cell 2 88 2 88 2 88 90 90 90 Define the scattering plane SICS addauxref 2 0 0 SICS addauxref 0 2 0 SICS makeub 12 Calculate and activate a UB which has been derived from the cell constants alone Drive the instrument to the calculated A4 position SICS dr a4 position Find the peak 2 0 0 and optimize it Once you are at the maximum SICS ref 2 00 Peak QL A4 SGL SGU 1 2 00 000 0 00 65 31 87 21 125 5 22 Make an axiliary UB and drive to the theoretical position for 0 4 4 SICS dr qh 0 44 Find the 0 4 4 reflection and optimize Once you are at its maximum SICS ref 044 Peak QL A4 A3 SGL SGU 1 0 00 4 00 4 00 65 31 87 21 1 25 5 22 Show the complete peak list SICS ref Peak
19. d 15T magnet MA15 7 1 Regulations and Specifications The forces on the magnet may not exceed 100 kg Under normal operation conditions the forces from the monochromator shielding exceed this value and requires an extension of the monochromator sample distance The operation of MA15 on Rita II is thus only allowed for the following conditions between 3 0 and 17 0 meV at a distance of 450 mm or more up to 14 9 Tesla between 3 0 and 8 0 meV at a distance of 410 mm or more up to 13 5 Tesla between 8 0 and 17 0 meV at a distance of 410 mm or more up to 11 5 Tesla For any other configuration force tests have to be done How the distance has to be measured In this example the distance is around 400 mm 37 THE 15 VERTICAL MAGNET MA15 7 2 Installing MA15 The 15 T magnet requires a completely non magnetic environment The goniometer motors thus have to be removed and replaced by a rigid support which does not allow for any tilt The magnet also does not allow for any rotation The sample table motor OM A3 can thus be not used and is replaced by a rotating sample stick Remove goniometer from the sample table Only unscrew the 4 screws connecting the goniometer with the sample table Do not take the goniometer apart Unplug the cables for the goniometer and translation motors see picture below Unscrew here 4 screws Unplug cables here Screws holding omega motor 6 screws 38 THE 15 VERTICAL MAGN
20. de number ca A OMA 2 deg A OMA 3 deg Ay EEE 4 2 Sr 5 9 e Distance from central beam pixels Distance from central beam pixels 1 1 4 5 6 7 3 4 5 6 Blade number ca Blade number ca Peak position on the PSD for the different blades for a postive E 5 meV 31 RITA MODES Chapter Data Treatment and Analysis 5 1 Data Format NeXus is a joint effort of both the synchrotron and neutron scattering community to develop a common data exchange format based on a hierarchical data format HDF As physical file format the HDF from the National Center for Supercomputing Applications NCSA was choosen This is a binary platform independent self describing data format HDF is well supported by major data analysis packages HDF files are accessed through a library of access functions This library is public domain software Libraries are available for the ANSI C Fortran77 and Java programming languages on all important computing platforms term hdfview T ler File Window Tools Help File URL afs psL ch project sinqdata 2007 rita2 001 11222007n001258 hdf M 1 322007n001258 haf fats psi ch project sinqdata 2007 rita2 001 11322007n001258 hdf entry1 data Qh Genny 4 SRTA analyzer Ca contro 2 2 2025 12039 9 COI 2 0082 2 0221 12 036 12 0049 2 0188 2 0328 um 12 0019 2 0158 2 0298 Ra
21. e from SICS The following commands are available SICS e1737 getthreshold 1 reads the current threshold SICS 1737 setthreshold 1 value sets a new threshold Typical values are 20 to 50 21 SHORT USER MANUAL 2 6 4 Monochromator Curvature The curvature of the monochromator is controlled by the motor CUM which turns the blades The optimal curvature depends on the spectrometer energy and is given by CUM vbl vb2 sin omm with vbl 0 307 and vb2 8 90 as of April 2007 These values can be changed by the command SICS tasub mono vb1 value SICS tasub mono vb2 value The gain in intensity compared to a flat monochromator is about 2 5 as can be seen from the figure below RITA 2 Eichung CUM E 14 68 meV LL Mai 2002 Position Mox Intensity Int Intensity fahm Gaussion fwhen Larentzian 50 534 0 86 348 2 135754 2765 566 2 5 Int Intens Exp Bg Fos dBg dx 11849 335 183 4 x 40 7 1 043 0 798 Monitor 10000 0 8629 vanjus11 dat 1 1 1 2 6 5 Scattering Sense Most experiments are done in a sm 1 ss 1 and sa 1 configuration where 1 means scattering to the left and 1 scattering to the right Sm and sa can only be 1 only the scattering sende at the sample can be changed by SICS se ss value or SICS tasub ss value 22 RITA MODES Chapter Rita Modes this chapter we describe the different modes which are available at present for electing the analyzer mode is an impo
22. ed by gold foil activation and are given in the figure below Neutron Flux Measurements at SINQ gold foil activation latest status july 2004 2 39 10 2 00x 10 Flux values measured with lead target target4 mark 3 Flux values measured with circalloy target target mark 2 scaled to laed target factor 1 45 Litiy Koordination Betrieb Anlage West S931 The SINQ instrument hall at PSI showing the neutron beam line from the source through the guides to the spectrometers RITA2 is located at the position of the former Dr chal triple axis spectrometer The flux measured by gold foil activation is also shown Focussing mono SINQ current 1020 uA 1300 r Ml Time ki s 600 Intensity versus wavelength given as monitor counts per second 500 3 5 4 4 5 Wavelength Aangstrom 1 2 Monochromator The RITA II monochromator consists of 5 vertical x 3 horizontal PG 002 vertically focusing crystals of size 5 cm width 2 5 cm height The mosaicity is 40 in both directions The curvature of the monochromator is controlled by the motor CUM which turns the blades The turning of the blades is given by CUM in arbitrary units for blade 2 and 4 twice that amount for blade 1 and 5 The optimal curvature depends on the spectrometer energy see chapter 2 The proper curvature is automatically set by most s
23. he slits are made from four 10 mm thick BN plates which attenuate the beam by more than 4 orders of magnitude Each of the four plates has a motor connected For the monochromator slit the motor names are MSL MSR MSB and MST the third letter denotes left right bottom and top respectively The slits after the sample are SSL SSR SSB and SST The analyzer slit motors are named ASL ASR ASB and AST and the detector slit motors are DSL DSR DSB and DST All eight motor values are in units of mm Neutron monitor and motorized slit after the monochromator 1 6 Filters RITA II has two radially collimating filters a Be and a BeO filter The filters are meant to be placed right before the analyzer tank to filter out elastically scattered neutrons in an inelastic experiment The filters a placed on a special holder and can easily be drawn in or out of the neutron beam The filters are cooled with liquid nitrogen and have a hold time of 36 h when pumped out well The filters have to be aligned The rotation angles are 4 degrees for the BeO filter marked on the filter support and 0 degrees for the Be filter Pictures of the BeO filter and the filter support The filter can easily be pushed into or out of the beam 1 7 Analyzer 1 7 1 The analyzer tank The tank housing the whole analyzer detector system is shown in fig 1 The outer walls are made from a mixture of polyethylene and boric acid and the in
24. important It is seen in figure that the rest of the blades intersect the detector nearly pairwise in distances increasing with the blade distance from the central blade Plotting these distances from the central blade as a function of blade number gives a parabola see figures at the end If the angle OMA is above or below the perfectly aligned value the centerof the parabola will be shifted and the intersection of the beams will not be pairwise see figure 1 b and the figures at the end 29 RITA MODES This section will describe alignment of OMA and the analyzer blades using the point to point focusing mode The energy is set to Er 5 meV corresponding to 2TA 74 17 First invoke this mode by ritamode focus making sure that all the blades are free to move Place a vanadium or plastic sample on the sample table Run cascan macro This will scan each blade one at a time leaving the others parked at 0 After each scan a pixscanx of the PSD i taken at the most intense position of the blade This gives the position of the blades reflection on the PSD The macro gives a table showing the old position the maximum intensity position and the position on the PSD of each blade Plot the positions of the blades versus blade number and connect the points with a parabola The position of the center of the parabola gives the error in OMA The figures at the end can be consulted to determine the magnitude of the error Now move OMA by
25. is one specialty however The command SICS sync synchronizes the parameters and limits in the simulation server with those in the instrument 2 6 2 Batch files To see the batch file path SICS exe batchpath To change the batch file path SICS exe batchpath newpath e g SICS exe batchpath home rita2 batch To write a batch file Produce a text file with a text editor of your choice emacs kate etc term kate test01 job amp Write the commands directly into the text file as you would have done at the SICS client Save the file in the batch directory defined above To execute the text file type SICS do test01 job The batch file can not be changed once it is executed A workaround this limitation is to call another batch file at the end of the file 20 SHORT USER MANUAL Example of a batchfile dr ef 5 ritamode monoim dr tt 10 wait 600 dr mf 5 title H L scan E 0 7meV H 5T sc gh 0 5 0 0 98 0 7 dqh 0 005 0 0 0072 0 41 mn 200000 dr mf 0 title H L scan E 0 7meV H 0T sc gh 0 5 0 0 98 0 7 dqh 0 005 0 0 0072 0 np 41 mn 1e6 title energy scan at 1 0 1 0 sc qh 10 1 1 5 dqh 0 000 1 np 41 mn 2e5 do nextjob job 2 6 3 Counter Box Threshold To prevent collecting background data in case of no beam or a very low beam a threshold value should be set on the PSI counter box In TASCOM this was done by the command CIBO and setting the threshold manually The PSI counter box is now accessibl
26. nces marked with SICS are meant to be written in the command line in the SicsClient e entrances marked with term are meant to be written on the console g ina xterm 2 1 Introduction to SICS SICS SINQ Instrument Control System is a client server system that controls all neutron spectrometers of SINQ There is a magic server program running on the instrument computer which does all the work The user interacts with SICS only with client applications which communicate with the server through the network Most instrument hardware motor controllers counter boxes etc is connected to the system through RS 232 serial connections These RS 232 ports are connected to a terminal server which is accessed through another server program the SerPortServer program which is also running on the instrument computer The SICS server communicates with the terminal server and other devices through the network The program was written by Mark Koennecke and a detailed description can be found in the SICS manual 11 SHORT USER MANUAL Terminal server Motor Controller Motor lt gt RS 232 Controller Ge Data JAquisition Computer TCP IP Histogram Memory FIGURE 1 1 Hardware Setup at SINQ 2 1 1 RITA 2 Configuration pc4345 rita2 Instrument computer running Linux Insgpib01 TCP IP GPIB bridge psts216 Terminal server All ports configured 9600 8 1 no parity no flow cont
27. ntre of the sample table is placed 1 406 m from the monochromator axis This table is designed to hold one of Rises cryostats or magnets see the page about the auxiliary equipment Alternatively an open air sample holder a monitor holder or an Eulerian cradle may be put on the table The maximum dimensions for cryostats on the sample table are approximately given by the Riso 9 T magnet height 150 cm diameter 44 cm weight 450 kg The sample table is shown in Fig 1 Figure 1 Pictures of the sample table at the RITA II spectrometer The sample table is rotated by the motor OM A3 the corresponding 20 angle is called 2T A4 The maximum movement of 2T is limited by the neutron guide and hence depends on the value of 2TM as given in the following table Energy meV 3 7 5 13 68 14 7 2TM 89 0 74 16 42 76 41 18 Maximum in 2T 118 115 90 81 Above the turning plate there are two translations motors TU and TL in units of mm and above these are two goniometers GU and GL measured in degrees The height from the top of the sample table to the beam centre is 110 mm Cryostats magnets and open air sample holders are constructed so that the height from the sample mount to the beam is 57 mm 1 5 Motorized slits There are four optical benches Before and after the sample and inside the analyzer tank before and after analyzer Each can hold a motorized slit T
28. ory the data files are grouped in subdirectories for each 1000 data files named 001 002 003 etc All data files produced are stored in these directories according to the year and number they were obtained The data files have the general syntax rita2yearnxxxxxx hdf with xxxxxx 6 digits the run number of the file and year the year of production e g home rita2 data 2010 001 rita22010n001258 hdf Routinely all new data files are backed up immediately on the machine Insa15 psi ch which is accessible through the AFS file system at PSI Within UNIX environment one has to get access to the directory root afs psi ch project sinqdata 2010 rita2 and then to the desired data subdirectory From there one can copy files to other disks etc afs psi ch project singdata 20 10 rita2 00 1 rita22010n001258 hdf 5 3 Data Analysis 5 3 1 Data Conversion You can convert the hdf data into an ASCII file which you can then import into your favorite data analysis program term hdf2ascii filename converts to filename asc in the current directory 5 3 2 Matlab Routines Log on to the Rita computer term ssh rita2 rita2 Ask local contact for password term cd matlab setup the necessary path info in mypaths 33 SAMPLE ENVIRONMENT CONTROL Matlab s hdf2spec filename scanvariable flag e g s hdf2spec afs psi ch project sinqdata 2010 rita2 001 r1ta22010n001258 hdf E5 1 Creates a 1x7 specld object Flag 0 1 divides 1
29. rol if not stated otherwise Ports port 2 EL734 motor controller port 3 Rise temperature log port 7 Lakeshore temperature controller 12 SHORT USER MANUAL 2 2 Starting SICS 1 Check if the SICServer is running term ps A grep SICS should report at least one line ending with term SICServer rita2 tcl If not type term startsics For this you ll have to be user rita2 on the computer rita2 psi ch 2 Start the SicsClient term sics amp a new window will open 3 Activate SICS via the pull down menu in the SicsClient Connect RITA2 and 4 Authorize Enter User Name and Password standard user name and password are rita2user and 03Ins1 5 Start the status window term rita2status amp 6 Activate the status window via the pull down menu Connect RITA2 7 An online plot of the PSD can be obtained by term sansstatus amp 8 Activate the status window via the pull down menu Connect RITA2 2 2 1 Six six is an alternative to the standard Java SICS commandline client Why an alternative SICS client e It is much faster It does not need the X window system It connects automatically to the instrument if you are logged into the instrument computer 13 SHORT USER MANUAL It has the full functionality of the standard commandline client but no graphical interface This means you can not and have not to use the mouse there are no colors to distinguish commands responses and er
30. rors instead of clicking on the interrupt button you have to enter stop the history is only accessible with the arrow keys 23 Drive Check and Modify device parameters The current value of a device is reported by just typing its name SICS lt device gt There are hardware and software limits for all motors These can be checked for an individual motor by typing SICS lt device gt list To change the software limits type SICS lt device gt softlowerlim lt value gt e g SICS ca5 softlowerlim 200 SICS lt device gt softupperlim lt value gt For PSI motors and encoded RISOE motors 2t and 2ta repositioning should be done by the command sp which changes the softzero value SICS sp device lt value gt sp e g SICS sp omm 37 07 Repositioning of unencoded RISOE motors can be done by the command SICS lt device gt putpos value e g SICS oma putpos 74 17 This is however at the present state of development not working properly for all motors The hardware limits can not be changed Drive a device to a value SICS dr ive device lt value gt Drive several devices at the same time SICS dr ive lt device1 gt lt value1 gt lt device2 gt lt value2 gt etc 14 SHORT USER MANUAL 2 4 UB Matrix and Crystal Alignment SICS cell a b c alpha beta gamma set unit cell constants If b or c are omitted the same value as for a is used if angles are omitted they are set to 90 degress Without arguments
31. rtant issue for the RITA II spectrometer In standard operation 3 1 Two axis and three axis modes The spectrometer can be run both in two axis and triple axis mode There are 2 triple axis modes ki and kf fixed incoming or fixed final energy Usually the kf option is used There is only one 2 axis mode elastic To read which mode the spectrometer is in write SICS tasub const To change the mode write for instance SICS tasub const elastic To avoid a shadow from the edge on analyzer in two axis mode one may like to turn away OMA to e g 90 degrees and lock it by SICS fix oma 3 2 Flat mode This mode is selected by the command SICS ritamode flat The nine bladed analyzer is made flat all cai zero and oma equal to omm In standard triple axis notation A5 Al 23 RITA MODES 3 3 Monochromatic point to point focusing mode A monochromatic point to point focusing mode which produces a reasonable E resolution and a relaxed Q resolution is obtained by SICS ritamode focus This mode focuses the beam on the central part of the PSD Analyzer configuration in focusing mode The 7 blades focus the beam on the central part of the PSD The outer parts of the PSD are covered up by borated polyethylene pieces which can be screwed to the detector housing 24 RITA MODES 3 4 Monochromatic imaging mode The monochromatic q dispersive mode is now fully operational and can routinely be used for experiments It
32. side of the stainless steel tank is covered with 5 mm boron containing plastic This construction minimizes the neutron background as most of the fast neutrons are thermalized by hydrogen in the thick walls while thermal and cold neutrons are absorbed by the boron nuclei The walls have an Al opening where neutrons scattered at the sample enter the tank Here a collimator may be inserted Secondary PSD Beamstop EC cox Figure 1 Sketch of the RITA2 analyzer tank For monitoring the equipment inside the tank a small video camera is placed inside the tank and the output is displayed on a video monitor on the control platform Entrance to the tank is easy accessible by opening the tank doors see fig 2 An optional front shielding is shown on the figure too Further additional shielding for the inside of the tank is available 1 7 2 The nine bladed analyzer The nine bladed PG analyzer at the moment only 7 blades are installed of the RITA II spectrometer is shown in fig 3 The blades have the dimensions 24 150 mm and are mounted on vertical axes each with its own motor The nine motors are named CA1 through CA9 where the angle is given in degrees and they are in turn mounted analyzer module with a distance of 25 mm between them The analyzer axis is located 120 7 cm from the center of the sample table The analyzer module is also able to rotate around a
33. subtracting AOMA and remo to the value it had before i e if OMA is 74 17 and AOMA is found as 2 set OMA 76 17 and remo to 74 17 Move the ca motors according to the movement in OMA BUT note that the values of the ca motors rise clockwise opposite to all other motors where the values rise anticlockwise This means that the ca s must be compensated in the same numerical direction as OMA If the change in OMA angle is considerable more than 1 2 the blades should be recalibrated with the cascan macro as the asymmetry means that the blades can not be compensated by exactly the same amount as OMA is moved 30 RITA MODES A OMA 3 deg A OMA 2 deg 4 T T T 47 71 2 2 x x amp 4 E E i 3 8 g1 g1 2 9 S s 2 i 2B a a 1 1 i 1 1 1 1 1 1 1 1 1 1 2 4 5 6 7 8 2 3 4 5 6 7 8 Blade number ca Blade number ca A OMA 1 deg A OMA 0 deg 3 r r N N Distance from central beam pixels Distance from central beam pixels 4 5 2 3 4 5 6 7 8 Blade number ca Blade number ca Peak position on the PSD for the different blades for a negative E 5 meV A OMA 0 deg A OMA 1 deg pixels co Distance from central beam pixels Distance from central beam EA 4 5 6 0 3 4 5 6 7 8 Blade number ca Bla
34. the cell constants are listed SICS ref qh qk ql a3 a4 sgl sgu Ei Ef Make an entry in the list of peaks For angles and k values not given the current motor positions are used If the given qhkl triple already exists its list entry is overwritten If not a new entry is made The peak number and the peak data are returned SICS addauxref qh qk ql Add an auxiliary reflection to the list of reflections A4 is calculated from the cell constants the current ei and ef values are used A3 is left alone or is calculated to have the right angular difference to the previous reflection Using auxiliary reflections is a help during setup of the instrument or in powder mode The sequence SICS ref clear SICS cell aa bb cc alpha beta gamma SICS addauxref ax ay az SICS addauxref bx by bz SICS makeub 1 2 with ax ay az being the first plane vector and bx by bz being the second plane vectors creates a UB matrix which allows to drive QE positions and qm But be aware that a3 sgu and sgl values are still invalid SICS ref clear peak Remove a peak SICS ref clear all Remove all peaks SICS ref List all peaks SICS makeub peak1 peak2 Calculate activate and print out the UB matrix as well as the peak list with qhkl values calculated back Peak 1 is used as the main peak driving to the angles given for this peak will correspond to a QHKL which may only differ by a scalar factor of about one if the cell constants are not corre
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