MIRSI Operator`s Guide - Harvard-Smithsonian Center for Astrophysics
Contents
1. 4 da a a HEN EJ AE 4 d 0 1 233 ICH 2 M uc E A 22 IE E 5 pi 18 rn Ground SESESECESESESE E EN DEWAR SIDE ITT Cannon 4 Amphenol 32 pin connector 4 pin connector MS3116F18 32S 97 3101A 14S 2P w stress relief 97 3057 1007 1 foot 4 conductor 16 gauge cable w braided shield ALPHA MIRSI Operator s Guide Peripheral components 4 Amphenol 4 pin connector 97 3106 145 25 w stress relief 97 3057 1007 PIN OUT 20 ft 4 conductor 16 gauge cable w braided shield ALPHA 4 Harting PHYTRON BOX 8 pin connectors Han D7 pin male insert Hoods 09 20 003 042 0 Strain Relief Olflex Cable X11W N MOTOR 1 MOTOR 2 MOTOR 3 MOTOR 4 8 ground MIRSI Operator s Guide 20 2 twisted pair 28 Gauge braided shield 1 ft twisted pair 20 Gauge braided shield DEWAR SIDE ITT Cannon 26 pin connector MS3116F16 26S Amphenol 6 pin connector 97 3101 A 14S 6P w stress relief 97 3057 1007 PIN OUT Amphenol 18 pin miniature connector 14 18 A 1 ft 8 twisted pair 28 Gauge braided s2. BER AUGE EU as 23 3 9 2 Operation of temperature controller epi Hahn 24 3 9 3 Operation of temperature SS 24 39 4 Temperature LOR IT rl e 24 T 25 SAD Secondary do datos 25 3 102 Balan E de 25 4 OPERATING MIRS sarao iii dan Sri ARTIS EH IN OR NURSE PENSA kishia 26 5 OBSERVING AA O 28 5 1 Telescope interface IRTE noU Xe be ERE e Polo reru pha 28 5 1 1 Sending commands to the Telescope Control System 28 2 12 C HODBIBE iii doo cte EE MED UEM IU 28 5 1 3 aR 29 Sul dC OU QUOD CE EAR 29 a Wists islet ie Bleeker a 29 5 1 6 Standard stars euet a ein 30 5 1 7 Telescope offsets and dither mosaic procedures nn Ra 30 82 A A 30 MIRSLOBSERVING aros 31 MIRSI SETUP u a rc AN e Ural 32 MIRSECRYOGEN LOG 34 LOS END OF RUN TASKS ep 35 APPENDIN A MEME 36 22552256 ponet EIS en ANE aou 37 MIRSI NIGHTLY O
3. gt LP 5 3 AR 3 en al gt Uu gt gt zo pr f aya dH 5 AM 3 AL 5 AL 5 AK 3 5 AI 5 5 AH 3 AGS AG 3 AE 3 BG 1 BF 1 a m SEN BIS Biro als e jaj 5 Sjo 9 9 gt gt gt WW Siw gt gt Bu a 26 27 28 29 30 31 34 35 36 37 38 BE 3 eS EN aJo oo ar P gt a INS alo Ss 8 OJO wojo w OJO O R EE gt ala PIL gt zg zZ gt gt gt gt ojo I co TE NYO 68 96 Pin backplain 29B power supply Alcopian Out 14 18 22 Takt1 3 amp Takt4 grounds power supply Alcopian wire wrapped to amp 25 p 5 out 17 Takt1 3 4 Takt1 3 21 Taktt 3 8 Takt1 3 25 Takt1 3 12 Takt1 3 17 Takt4 4 Takt4 2C MIRSI Operator s Guide Chop driver board Leach Box Chop and Nod Fiber Optic Output Board ul 31 from 96 Pin 78 15 pl OUTle e cz 6 297 con 2 Agilent Agilent Transmitter U HEBR 1414T HEBR 1414T C28 from 96 Pin 111085 OUT E 10 ES col N su A25 from 96 Pin Status A28 from 95 Pin AS from 95 Pin MIRSI Operator s Guide BNC chop box
4. 13 Case 7 4 esas 13 2 5 Suggested shipping crate labels and orientation markers 1 eere 13 3 1 Unpacking and inspection iocus cre 3 2 Host Conipuler T 18 3 3 System Check oo PRENNE LD MIOS a s A doe Sah ad 19 19 3 4 Dewar evacuation using vacuum 2 sese ense essa seen ease esa sees so sees osse es 19 3 5 600100 2 20 e AAA 20 3 32 He cold WA 20 3 6 MOUN 20 3 Camera Electronicos UL Sv d Blectromiesselupe ra a UE dut 21 3 7 2 Source Follower Gain 1 amp erre eee stre het 22 3 8 Motor Control Syste REA 3 9 Temperature Controls extr OR DNI RIS E avt RR RI 20 ore DUNT
5. CHOP LOW Idle frames m The frame and chop parameters can be set from the host program using the following manual DSP commands SNC Set number of coadds for the exposure SET Set exposure time i e the frame time in integer number of expose clock cycles In grab mode the total on source time is determined by N coadd x Frame time The total acquistion time is determined by coadd x Frame time Global reset Post reset delay Readout time SCC Set chop command 0 grab mode 1 chop mode SFC Set frames per chop number of frames on source per chop cycle SCW Set chop wait number of idle frames clocked between chop levels SNL Set nod level 0 beam A 1 beam B sets DSP nod bit to desired level not used at IRTF From this scheme the total amount of time to acquire the exposure can be calculated Since the frames are readout out in integer numbers the exact value of acquisition time and chop parameters will be the sum of integer frame times expose and idle The mirsi host program makes these calculations when the user enters the observing parameters portable program mpars c is available in home camera This program can be compiled using the UNIX command gcc mpars mpars c Afterwards type mpars to see the usage options The programs first compute the number of frames per chop SFC l SCW x Idle _ frame time Total _ frame _ time 2 Chop _ frequency where Total_frame_time
6. Agilent Receiver HFBR 2616T r5 y 5 V Be 05 0574451 RT 5 v 390 o Agilent Receiver N Red RA 261 6 390 5 V C Green R9 45v 390 7451400 BNC Chopk 1
7. Frame_time Global_reset Post reset_delay Readout_time The total acquistion time is then 2 N _coadd x SFCxTotal frame time SCW x Idle _ frame time Total acquisition time SFC and the total on source time is still N_coadd x Frame time The controller has only modes for grab and chop The host program has the controller treat a nod set like two separate exposures Thus when in nod mode the acquistion time is double the grab or chop MIRSI Operator s Guide acquisition time The host program then writes a nod set as a single FITS file with up to 3 FITS extensions MIRSI Operator s Guide SYSTEM TAPE BACKUP To backup the MIRSI host PC use a 12 GB 4mm DAT tape 20 GB is too large There is a backup script to assist with the system tape backup procedure in home root backup The directories to be backed up include home opt and mirsil If space permits also backup mirsi2 To run the script Log in as root Type cd home root backup Is to see the date of last backup Check the MIRSI lab notebook for that date to see which tape A or B was used and insert the alternate tape if funding allows a better scheme is to use a new tape for each backup date e Edit the backup script to include mirsil and or mirsi2 depending data backup status and space available Edit the e mail address in the script where the notification message is sent Type backup The backup script will start and automa
8. 1 small 10 medium or large 60 custom dither pattern of an arbitrary number of steps can be created in a file with 2 columns of offset e g example off Note the last two rows are 0 0 0 0 5 0 0 0 5 0 5 0 0 0 10 0 0 0 5 0 5 0 5 0 10 0 0 0 0 0 0 0 0 0 0 0 and subsequently uploaded by the host software The directory for offset files is currently home camera Offsets Automated mosaic patterns are available as 2x2 3x3 or 4x4 field patterns The current default field of view is 60 There is an option to load a custom mosaic file analogous to a custom dither file Once the observing parameters and dither and or mosaic patterns are specified simply click Expose to start the sequence then sit back relax and enjoy the show 5 2 Log sheets The following sheets were created to assist in the planning execution and documentation of MIRSI observations and cryogen usage The Observing Plan sheet is optional but please use the setup observing log and cryogen log sheets whenever observing with MIRSI 30 Site Date Latitude MIRSI OBSERVING PLAN Longitude Local time UT time Sidereal time Observer Object name Type epoch DEC Airmass 15 00 15 30 16 00 16 30 17 00 17 30 18 00 18 30 19 00 19 30 20 00 20 30 21 00 21 30 22 00 22 30 23 00 23 30 00 00 0
9. inserted where the PEM stud goes through the bracket with the flat part flush along the top of the bracket Secure the PEM studs with 14 20 lock nuts e Attach the upper bipods to the mount plate using the 72 20 bolts and lock washers Use a mechanical lift to bring the mount plate and bipods up to the MIM interface Bolt the mount plate to the MIM using the asymmetrical bolt hole pattern with 12 20 bolts and lock washers The directional orientation should be marked on the plate if not refer to drawings for correct orientation Use the mechanical lift to raise the dewar up to the lower bipods Be sure the small mount block is attached and pinned to the dewar between the fill ports Attach the dewar to the bipods using 12 20 bolts and lock washers 3 7 Camera Electronics WARNING Always use anti static mats and grounding straps whenever touching the electronics box or dewar connectors and cables 3 7 Electronics setup The electronics should be set up using the following procedure e After unpacking open the Leach electronics box and reseat all boards and connectors Connect the Leach power supply to the Leach electronics box Connect the electronics box to the host PC using a dual fiber optic cable Connect the chop signal from the electronics box to the chop drive box using a fiber optic cable At IRTF the nod signal is left open the host program sends nod commands to the telescope control system over the network
10. issues a Camera Power On command The best value for VDETGRV was determined to be where the signal to noise peaks as function of VDETGRV The bias voltage across the detectors is VGATE HIGH VDETGRV V thresh where V thresh is a diode threshold across the gate about 1 3 V PROBLEM Sometimes the software does not set the values and instead does nothing If when you expose you observe sky levels of 10 000 counts no matter what frame time is set reapply the Set Detector Voltages 12 From the Session menu open the Target amp Observer Info window Select the site and enter the observer and target object information 13 From the Display menu select the desired display mode difference pattern remove coad tile single 14 In the main window click Expose to start an exposure Note DO NOT Abort during an exposure only between multiple exposures If display image is selected then when the exposure is finished mirsi will automatically display the image in the ds9 window in the selected display mode For multiple exposures mirsi will automatically display each image after acquisition 27 5 OBSERVING WITH MIRSI 5 1 Telescope interface at IRTF 5 1 1 Sending commands to the Telescope Control System The MIRSI host software can send commands directly to the IRTF telescope control system over the network The IRTF program tcsio is used for this task tesio is installed on the host PC in the directory usr local bin Some
11. sample commands with tcsio are tcsio ABEAM Nod to beam A tcsio BBEAM Nod to beam B tcsio ra offset asec dec offset asec OFFSET Send arcsecond offsets to the telescope tcsio 0 0 0 0 0 1 The nod beams are by the telescope control system For more information see the telescope operator or other IRTF staff member 5 1 2 Chopping The chop throw is set by IRTF staff At IRTF chop rates should be tuned to avoid resonance frequencies of the secondary mirror 8 9 Hz or so The IRTF chopper should be set to Ext External when using MIRSI Larger chop throws require large chop waits When in chop mode the MIRSI electronics generate a binary chop signal bit from the Leach timing board pin named H4 otherwise known as STATUSO This chop signal is buffered on a separate chop drive board and converted to an optical signal by an LED source The optical signal is carried outside the Leach box by fiber optic cable to an independently powered chop driver box The chop driver box converts the optical signal into a TTL signal with BNC output A BNC cable should be used at the IRTF to carry the signal from the driver box to the chop bit input of the telescope control system When chop mode is selected in the MIRSI host program the timing software will automatically control the beam switching using the chop bit Chop rates are limited by the speed of the array readout The host program will convert the desired chop parameters into integ
12. 0 30 01 00 01 30 02 00 02 30 03 00 03 30 04 00 04 30 05 00 05 30 06 00 06 30 07 00 07 30 08 00 MIRSI SETUP Date Data directory Site Gain e ADU Readout noise e Pixel scale pix FOV x Chop wait ms Nodwait 5 0 ADU File Time Frame Chop Sky level ADU Overhead Ratio total Comments No UT um time ms freq Hz Blank subtract time on source time 22 4 9 7 8 8 7 9 8 N band 10 3 MLOF 11 6 12 282 12 5 18 5 20 9 25 9 CVF short CVF mid CVF long Grism 7 14 Grism 18 26 MIRSI OBSERVING LOG Page Date UT EEE 2 Data directory _ _ File Time Object Frame Exp Mode Chop Offset Airmass Comments No UT um time Time freq file off Purpose Focus FWHM dither throw ms s N CN Hz weather etc MIRSI CRYOGEN LOG DATE TIME TIME MIRSI MIRSI Storage Dewar Storage Dewar Liters mo day year Cryogen Begin Fill End Fill Level Before Level After Level Before Level After Used Comments AO ISS AAA 15 10 17 18 10 20 21 22 23 24 29 26 27 2
13. 8 29 30 31 32 E EA IDEE MIRSI Operator s Guide 6 END OF RUN TASKS Here is a check list for necessary tasks at the end of an observing run Mostly the shutdown procedure is simply the reverse of the setup procedure It will take three people about two hours to complete these tasks In the host software deselect the Camera Power on Home the all three filter wheels Exit the host software Backup all data onto tape and or a remote machine Install the dessicant trap Power down the Leach power supply Power down the motor control box temperature controller and temperature monitor Don wrist strap Remove clocks cable from the dewar Install a grounding cap on the dewar s 61 pin clock signals connector Remove the signal cable from JFET box Remove the JFET box from the dewar Install a grounding cap on the dewar s 46 pin readout signals connector Disconnect all cables from the Leach box and insert the 37 pin shorting plug in the 37 pin readout signals connector on the Leach box Disconnect the fiber optic cables for the Leach electronics and the chop nod driver box Coil and safely set aside the fiber optic cables Disconnect the temperature controller cable temperature monitor cable home switch cable and motor drive cables and pigtails on both sides Set all cables aside Insert grounding plugs into the 26 pin housekeeping and motor drive connectors on the dewar Disconnect all power cords from the per
14. BSERVING CHECK 1 18 38 Cieneral Star Up A O 38 O ME ER aiu EE t Aa a 38 MIRSI TROUBLESHOOTING 39 TIMING SCHEME CONCEPT EXPOSURE PARAMETERS AND IMAGE ACQUISITION TIME Lr 42 SYSTEM TAPE BACKUP nieta idad 45 WIRING DIAGRAMS nadal cus EUM OS 46 Electronics Box to boards wiring unse lo ii 40 CONTROLLER BOX 30 0 5 0 3 5 o 47 JEET cutrenp A Lt O 48 Peripheral components dans 49 Chop driver board 55 BING CHO py BOX ue eee 56 1 INTRODUCTION 1 1 MIRSI overview purpose of this manual MIRSI is a mid infrared spectrometer and imager that has been designed for operation at the NASA Infrared Telescope Facility IRTF on Mauna Kea Hawaii Its sensitivity at mid infrared wavelengths and multiple capabilities make it a state of the art tool for the study of star formation processes in the Milky Way planetary nebulae young stellar objects circumstellar dust and solar system ob
15. COL 37 VSUB wired Vdd1 Vdd2 amp Vdd3 38 VCAP 39 VOFFSET 40 VEN2TOI 10 CLOCK GROUND 26 DCBIAS GROUND 12 ROWSTRT 13 RRESTRT 14 RCLKI 15 RCLK2 16 ROWEN 17 RSTROW 28 CLCOL 29 VGGCL 30 SH 31 SHPCHG 32 CLOUT 33 VGATE 45 VGG1 46 COLSTRT 47 CCLK1 48 P2TOI 49 CCLK2 50 P1TO2 42 OUTPUT BIAS 11 CLOCK SHIELD 27 CLOCK SHIELD 44 CLOCK SHIELD DB 9 Male 1 amp 2 4 amp 5 6 9 CLOCK DRIVER BOARDS DB 37 Female CLOCK DRIVER 0 CLOCK DRIVER 1 0 3 gt 33 not attached 22 notattached 22 notattached 35 not attached 22 25 MIRSI Operator s Guide JFET current source box 41 female JFET Current 38 female to Signals cable from dewar Source Box sigaals cable 38 male 27 female B W 20 x 8 1 d gt 2 B D 0 22 t 2 E 23 Free d E Il E A lta LL 2 2 acLI TTL zu i 5 x mmis SEE RC cmm gt A a gt uL ne ES LIJOLT UT s 6 m T i 9 Vin j 30 t SLT Ton Y s a A AA 5 5 th is s 5 ELI JI LL
16. Connect the 37 pin readout signal cable to the Leach box and secure Connect the 50 pin clocks cable to the Leach box and secure Connect the readout cable to the JFET box Remove the 41 pin grounding connector from the dewar Connect the JFET box to the dewar Remove the 61 pin grounding connector from the dewar Connect the clocks cable to the dewar 21 3 7 2 Source Follower Gain test If running the detector chip for the first time since shipping the MIRSI observing team should perform the source follower gain SFG test The SFG test measures the response of the readout system from the pixels to the host PC by manipulating an artificial signal the pixels The detectors are turned off during this measurement which allows the measurement to be made when the detector is at room temperature as well as LHe temperature WARNING This test should only be performed by a trained MIRSI team member No guest observer should ever change the array voltages without explicit guidance from a team member Boot the host software Load the timing file home camera software SOURCE clkvrstuc tim lod Take a few images and note the overall level of counts From the Setup menu open the Bias and Clock Voltages window and select the one on the Clock Voltages LOW column for VRSTUC Enter 2 5 and press Update Selected Take a few more images The counts should increase by several thousand depending on the des
17. MIRSI Operator s Guide 9 LHe cooled work surface suddenly heats up to above 7 K A sudden increase in the temperature of the work surface may indicate one of the following problems LHe reservoir is depleted refill Motor currents have been left on To turn them off immediately press the INIT button in the host program Vacuum leak in the dewar Other symptoms of a vacuum leak include condensation and frost present on the exterior of the dewar If the latter symptom is present blow out the cryogens and put the dewar on the vacuum pump Stage heater 18 running MIRSI Operator s Guide TIMING SCHEME CONCEPT EXPOSURE PARAMETERS AND IMAGE ACQUISITION TIME This section of the Appendix contains concept diagrams for the MIRSI global detector timing scheme and the calculation of total exposure time for a given set of frame parameters MIRSI s timing scheme incorporates aspects of both Raytheon timing schemes Integrate then read and Integrate while read The beauty of the CRC 774 Readout Integrated Circuit ROIC is that it can be operated in several different Ways depending on the needs of the user The timing scheme for MIRSI currently consists of a destructive readout NDR This entails a global reset of the array all pixels addressed and set to their reset value followed by integration VGATE toggled to its high value During integration the multiplexer is clocked rows and pixels addressed in the usual sequence but th
18. Version 2004 01 22 Operator s Guide Joseph D Adams amp Marc Kassis Boston University Institute for Astrophysical Research Lynne K Deutsch amp Joseph L Hora Harvard Smithsonian Center for Astrophysics Table of Contents 1 1 MIRSI overview and purpose of this manual eee e eese eee ee seen ease eo sese es 4 1 2 MIRSI personnel contact info ss e eeeeeeeeeeeeeeeeee D 1 3 Engineering vendor contactsS ss ssseseseeeeeeeeee e 2 PREPARING MIRSI FOR AN OBSERVING 8 21 IRTF contact 2 Cryopgens at IRTE 2 3 Timescale guidelines 2 4 Packing inventory and weight distribution Y Case gt 185 IDS En et Nene ER m Ed enti tt Need 10 2160165 ET 10 3 1201 86055 Sn bn vitis 10 Case ERR 11 Case TSO rmn 12 Case 0
19. ats the inside of the dewar and boils off precious LHe and observing time Turn the motor currents off by immediately executing the INIT command from the host software see 4 3 9 Temperature Control 3 9 1 Setup MIRSI currently contains four silicon diode temperature sensors made by Lakeshore Cryogenics one on the rear of the cold finger which cools the detector one on the upper rear of the detector fanout board near the MDM connections one on the interior lip of the 77 K shield near the back plate where the optics box 23 can be opened and one similarly on the interior of the floating shield These sensors provide precision temperature measurements To read these sensors the set up steps are the following Connect the Lakeshore 321 temperature controller cables from the housekeeping color coded pigtailed cable to the controller s 6 pin sensor input and dual BNC jack for the heater output current The LOW side of the BNC connector is marked Connect the Lakeshore 208 temperature monitor s 25 pin input to the pigtailed cable using the temperature monitor cable Connect the pigtail to the dewar s 26 pin connector As usual all cables should be stress relieved nstall power cables on the controller monitor to standard power outlet If disconnected connect the 25 pin serial port A on the host PC to a null modem on the DATAPROBE input port Connect the 8 line gray serial line between the controller s serial I O
20. ched and the cold shutter is open during vacuum pumpout Bring the camera into the prep room the room containing the vacuum pump and cryogens Open the other crates and inspect the contents for damage Unpack the temperature monitor temperature controller and associated cables Connect them to the dewar and ensure the temperature sensors are reading appropriate values Begin recording temperatures If time permits unpack the host computer Check for loose parts and adjust if necessary Boot the host computer and connect to the network Again if time really permits connect the serial interface to the host computer and to the temperature monitors controller Boot the host software and begin the temperature log Otherwise temperatures can be recorded manually in the MIRSI lab notebook Connect the dewar vacuum valve to the vacuum pump Begin pump out Check that the L shaped mount electronics support bracket interface plate is attached to the dewar optics box face Attach the electronics support bracket to its interface plate Attach the Leach electronics box to the electronics support bracket Open Leach box and reseat all boards and connectors When the dewar reaches sufficiently low pressure 10 to 10 Torr first close the dewar valve then turn the pump off After the pump winds down vent the pump line and disconnect the pump line from the dear valve Attach the NW 40 safety cap to mouth of the dewar valve Close the cold shu
21. cking requires Open the CPU case and ensure that the boards wires connectors drives are secured Be sure that there are no loose screws floating in any of the computer device cases Open the Leach electronics box Gently reseat all boards and connectors even if they visually appear secure 3 2 Host Computer Unpack the host PC computer Before power up please open the CPU case and look for loose boards cables wires or free floating screws etc Also inspect the monitor for possible damage These quick checks will help to prevent irreparable damage to the computer if something became amiss during shipping Once the host PC is booted connect it to the network by doing the following or just run the script described below Log in as root Make copies of then edit the files etc hostname hme0 etc defaultrouter etc nodename etc inet hosts usr local rsi license license dat to accommodate the new network information which should be available from the observatory A script called setupnet scr is found in home root This script will copy pre existing files for a given network setup with suffix as hostname For example setupnet scr insguesta will copy the network files used at IRTF for hostname insguesta etc hostname hme0 insguesta etc to etc hostname hme0 etc Currently network files exist for host names mirsi BU insguesta IRTE and mlof5 Mt Lemmon These names be used as input arguments for t
22. d Chop Driver Box if they are not operating 5 Start the software Login as camera e Synchronize the UT time with the telescope if they are not within your tolerances by typing xclock digital Cupdate 1 amp and correct using the UNIX date command as root e From an open shell tool or xterm start the image display program using the command ds9 amp then start the camera host software with the command mirsi This starts the MIRSI user interface and image display software 6 Ifthe power on the stepper motor electronics is cycled or being turned on for the first time follow these instructions Power on the stepper motor electronics Immediately initialize the motors Open the Observing Commands Observing Parameters window under the Session pull down menu Press the INIT button near the bottom of the window REASON When the motors electronics are turned on the motor currents are active The motor currents add 3 W inside the dewar and will evaporate 16 L of He in a few hours 7 Start or continue the temperature log by opening the Temperature Control window under the Session menu Select Active 8 From the Setup menu open the Observing Setup to setup the electronics for the observing session A pop up window will request you to check the temperatures After the YES button is selected the mirsi shell window should report a done for each of the selected tasks in the Controller window If the shell reports that errors have
23. e pixels are not reset in order to keep the photo charge integrating After an integer number of clock cycles have occurred 1 e the frame time VGATE is toggled to its low value to halt the integration In the subsequent clock cycle the rows are addressed in sequence as usual but the pixels are reset and read out with A D conversion and coadding processes After a specified number of these frames coadds the image is transmitted from memory on the coadder boards to the host PC Between exposures the multiplexer is clocked continuously without integration using an idle clock cycle global reset followed by row clocking and pixel reset without integration and A D conversion In chop mode these idle frames are taken between chop levels while the secondary mirror moves between its alternate beams The chop high and chop low image buffers are stored in separate memory buffers in the coadder boards SRAM memory and transmitted to the host PC as a single large image The characteristic times are drawings not to time scale Expose frame gt lt _ gt lt 5 On Global reset Delay Expose clock Expose Clock Expose clock Expose clock Readout w pixel reset amp A D 1 124 ms 0 041 ms 4 028 ms 4 028 ms 4 028 ms 4 028 ms 18 13 ms Idle frame nn gt Global reset Idle clock cycle eo Te 4 63 ms total MIRSI Operator s Guide Chopping pattern CHOP HIGH Expose frames CHOP WAIT Idle frames HH
24. er frame readouts and display the updated results accordingly when the Apply button is pressed 28 5 1 3 Nodding Nod throws set by the IRTF staff At the IRTF telescope nod is controlled over the network using the tcsio program see 5 1 1 The host software automatically uses this command between exposures to nod the telescope The nod beams are defined using the telescope control system The commands tesio ABEAM and 080 BBEAM nod the telescope to the respective beam Note the chop driver box has a nod bit that is directly analogous to the chop bit The host software sends a command to the timing board to set or clear the nod bit before an exposure This nod signal is used at Mt Lemmon but not at the IRTF 5 1 4 Collimation To collimate the optical beam first close the mirror covers and open the hatch so that the secondary mirror sees the mirror covers and the camera is looking at the secondary Fine tune the dewar s pointing by slowly loosening the bolts on the bipods to tip tilt the dewar When the signal is maximum measure the gaps between the dewar and the bottom surface of the bipods using calipers or a micrometer Create shim spacers by peeling away layers on the bipod feet shaped shims until the shims are the correct thickness Disconnect the dewar from the bipods place the shims between the bipods and the dewar then bolt the dewar back to the bipods Next point the telescope at a bright star and defocus the star
25. eration profiles for motor motion and sends the pulses to the SINCOS drives Here are the steps to set up the motor control system Briefly open the motor control box and inspect for loose boards and wires e If disconnected connect the MIRSI host computer serial port A to the DATAPROBE breakout box There should be a null modem on the DATAPROBE master port Connect DATAPROBE 25 pin output A to a null modem A then the null modem to the OMS control board 9 pin input connector located in the Phytron motor control box Plug the four motor drive cable connectors into the Harting connectors at the rear of the motor control box Currently the fourth connector is attached to a spare cable Connect the motor drive cable pigtail output to the 32 pin connector on one of the dewar s feet next to the vacuum valve Connect the four motor control cables to the dewar at the pigtail The connectors should be color coded Ensure that the cable is stress relieved Plug the home switch temperature sensor pigtail cable into the 46 pin connector on the dewar Connect the home switch cable from the 25 pin output on the rear of the motor control box to the appropriate color coded pigtail connector Ensure that the motor control box power switch is off and then connect the power connector to a standard power outlet WARNING Note when the motor control box is initially powered on the motor currents are by default on and this rapidly he
26. eset and timing file download Press the white reset button a few times If that is unsuccessful recycle power on the Leach box a couple of times Eventually these tricks will work 3 Absence of photo signal in an exposure If the multiplexer is reading out correctly source follower gain test is successful but there is no photo signal in an exposure check for one or more of the following steps Detectors have been turned on must occur every time array is powered on Cold shutter is open Aperture wheel is sitting at the imaging or a slit position Both filter wheels are sitting on a filter and long wavelength blocker open position 1 no AI blank is in the optical path Frame time is sufficiently large enough for given filter 4 Certain channels exhibit radically different zero levels than the other channels Usually this occurs at the beginning of the night when the electronics are first powered up Try the following which work best after the electronics have been powered on for 5 10 minutes Power down the array by deselecting Camera power on Power on the array by selecting Camera power on If that doesn t work try Power down the array by deselecting Camera power on Power down the Leach box Wait 10 seconds then power the Leach box back up From software follow the usual steps to reset the controller and power up the array If that doesn t work try Power down the a
27. he setupnet scr script After setting up the network files reboot as root There may be some long pauses during boot but once the machine is fully booted it should have network access When MIRSI returns to the BU lab run 18 home root setupnet scr mirsi as root 3 3 System Check Ideally once the host computer is running and is on the network the operability of the electronics array and filter wheels should be verified Doing so allows any problems to be identified and corrected before the dewar is cold 3 3 Electronics After the Leach electronics boards are reseated check the operability of the electronics by connecting the 37 pin grounding plug to the box Leave the 50 pin clocks connector open don t short This will produce a zero signal Follow the instructions for connecting the electronics to the host PC described in 3 7 1 and for taking images described in 4 but load the timing file home camera software SOURCE zerolevel tim lod The electronics should cooperate with the commands given by the host computer Take a few images the level should be around 65 000 counts or so this corresponds to zero level due to an internal sign flip in the signal 3 3 2 Array Next remove the 37 pin grounding plug from the Leach box and connect the Leach box to the dewar as described in 3 6 Be sure the Camera Power On is deselected in the software or better still that the electronics are powered off Do the source fol
28. het extenders incl 7 16 socket cryo glove pairs 2 inflatable bladders 2 cable ties dewar window baffle Cables tape drive to PC PC to video monitor fiber optic cable pair 100 2 packed in cardboard box fiber optic cable pair 30 E spare fiber optic cable pair 3 motor drive signal clocks home switch temp monitor temp controller ethernet serial PC A port 25 pin to DATAPROBE input null modem serial gray DATAPROBE output null modem to motor box 9 pin serial gray DATAPROBE output null modem to temp controller 8 pin modular serial brown DATAPROBE output null modem to temp monitor 8 pin modular temp and home switch cable pigtail motor cable pigtail BNC cable for chop signal out 25 9 pin male to female extension cable for extender board 37 pin male to female extension cable i 99 11 Case 5 180 lbs Mount bipods 3 bipod feet shims 6 electronics support bracket 12 20 bolts nuts 1 20 flat amp lock washers 14 28 bolts 14 flat washers 14 20 lock nuts 3 8 16 bolts nuts 3 8 flat amp lock washers mount block screws amp pins 14 20 nylon brushings YA nylon spacers Documentation MIRSI Operating Manual MIRSI log sheets MIRSI lab notebooks MIRSI minutes amp correspondence Raytheon array test data Raytheon CRC 774 manual IRLABS dewar manual cooldown data for new dewar Phytron motor amp box manuals MIRSI Leach con
29. hield MIRSI Operator s Guide Amphenol LakeShore 321 4 pin connector monitor 97 3106 145 Sensor mating 65 connector 20 ft 2 twisted w stress relief dir 106 233 28 Gauge 97 3057 1007 braided shield 106 009 2 Amphenol E high clear 18 pin miniature F low black connector 6E 14 18S n 20 ft 8 twisted pair 28 Gauge braided shield Hmom K J anv 321 temperature controller 6 pin connector only five are used in our application Heater banana plug connector LakeShore 208 monitor 36 pin connector currently only 2 lines are necessary RIO Zzaom MIRSI Operator s Guide 20 ft 8 twisted pair 28 Gauge braided shield 36 ground 18 ground MIRSI Operator s Guide Amphenol Amphenol 8 pin miniature 8 pin miniature connector connector 25 Pin Male D Sub w hood and strain relief 20 ft 8 conductor 20 gauge shielded ft 8 conductor 20 gauge shielded 1 Phytr on Box 25 pin femail D sub connector X home Digital Ground Y home DG DG DG 5 VDC 5 VDC 5 VDC 5 VDC MIRSI Operator s Guide Wiring diagram on the OMS board ONC VME board 68 Pin osts 1 BG 3 BF 3 BE 1 BE 5 BD 3 BC 3 5 5 o ls AX NIS gt Slo gt gt AW 3 AU 5 gt lt a
30. ignated range of the A D converters usually 0 5 V set in the timing source code Note the response is usually best at LHe temperatures Now update VRSTUC LOW to 3 Take a few images The counts should increase by a similar amount i e there should be linear response with changing VRSTUC LOW The SFG can be calculated using the following formula SFG AV ou AVin Where Naau AD_RANGE 65535 x LEACH GAIN and is the change VRSTUC VRSTUC HIGH VRSTUC LOW or 2V VRSTUC LOW The AD RANGE is typically 5 V and the LEACH GAIN is 2 The SFG is specified at roughly 0 6 Thus a change in VRSTUC of 0 5 V should produce a signal swing of about Naa 13 000 counts If the AD RANGE is 10 V the swing will be about 6 000 counts If the SFG test is successful turn the camera power off If the camera is cold 4 K follow the instructions for operating the camera in observing mode will require loading a different timing file 22 3 8 Motor Control System MIRSI contains three cryogenic stepper motors fabricated by Phytron to turn the filter and aperture wheels The components used to drive the motors are housed in the Phytron motor control box This box contains three SINCOS current drivers that turn the motors which are controlled by an Oregon Micro Systems OMS intelligent control board The OMS board communicates with the host PC over an RS 232 serial line computes the position velocity and accel
31. ill port keeping the tube as far down as possible without obstructing the venting gas The temperature of the cold surface should start dropping within a minute or two Once liquid starts to collect in the reservoir the venting plume should decrease noticeably and the temperature should drop rapidly to below 10 K The pressure in the LHe storage dewar should be kept at 1 3 psi If the pressure drops below this level pressurize it by cycling warm He gas into the storage dewar using the inflatable bladder or cylinder of GHe The reservoir will fill up in 30 40 minutes liquid will begin to shoot out of the fill port remove the fill line immediately depressurize the storage dewar and remove the fill line Measure the LHe level in the storage dewar and record results in the MIRSI cryo log The hold time for this initial fill should be 12 18 hours Once the LHe transfer is completed top off the LN reservoir Attach the flow meter to the LHe fill port and mount to the dewar appropriately Attach the boil off hose to the fill port 3 6 Mount 20 Attach the interface plate for the electronics support bracket before shipping MIRSI e Attach the electronics support bracket to its interface plate on the dewar using 14 28 hex head bolts and flat washers Attach the Leach electronics box to the electronics support bracket Use 2 nylon spacers on each PEM stud against the box surface Insert a nylon bushing is
32. ing Box 6084 75 Coromar Drive Santa Barbara 93160 Bldg B2 MS 8 Mr Robert Bob Mills Sr Focal Plane Engineer Raytheon Electronic Systems Infrared Operations PH 805 708 5084 Goleta CA 93117 3090 FAX 8 5 683 2462 PH 805 562 4064 jwock earthlink net FAX 805 562 2127 remills west raytheon com Mount Design and Fabrication Mount design amp bipod fabrication Mount fabrication Mr John Polizotti Mr Robert Bob Vere Project Manager Harvard Smithsonian Center for Astrophysics Boston University Scientific Instrument Facility 60 Garden Street 3 Cummington Street Cambridge MA 02138 Boston MA 02215 jpolizotti cfa harvard edu PH 617 353 2614 or 617 353 5056 PH 617 495 7466 FAX 617 353 6021 vere bu edu 2 PREPARING MIRSI FOR AN OBSERVING RUN 2 1 IRTF contact info Hilo office Institute for Astronomy IRTF Manoa office Institute for Astronomy IRTF 640 Aohoku Place 209 2680 Woodlawn Drive Hilo HI 96720 Honolulu HI 96822 808 932 2300 808 988 3893 FAX 808 933 0737 FAX 808 988 3893 Summit 808 974 4209 FAX 808 974 4212 Shipping Attn George Koenig Hilo address koenig irtf ifa hawaii edu 808 974 4209 Instrument interface and cryogen coordination Lars Bergknut summit bergknut ifa hawaii edu 808 974 4210 Administration Karen Hughes Manoa Hughes irtf ifa hawaii edu 808 956 6795 Observing Requirements Form http irtfweb ifa hawaii edu userSup
33. ipheral components Disconnect the serial lines and connectors between the host PC and the DATAPROBE box and between the DATAPROBE box and the peripheral components Dismount the Leach power supply chop drive box temperature monitor temperature controller motor control box and DATAPROBE box Dismount the dewar Dismount the Leach box from the electronics support L bracket Unscrew the electronics support L bracket from the dewar Leave the interface plate attached to the dewar Remove the flow meter and hoses and blow out remaining cryogens in the dewar Unbolt the mounting plate from the telescope and remove Remove bipods from the mounting plate Halt the host PC Disassemble the host PC monitor tape drive keyboard and mouse Pack the crates with care Label the crates under the same airbill Notify George Koenig that MIRSI is ready to be shipped The IRTF staff will haul the cases down to the IfA Hilo office After George confirms MIRSI is in Hilo contact Fedex and have them come and pick up the shipment at the IfA Hilo Office MIRSI Operator s Guide APPENDIX This appendix contains check lists for MIRSI setup nightly tasks a troubleshooting guide and wiring diagrams for major electrical additions and or rebuilding jobs 12 13 14 15 10 17 18 10 20 21 22 23 24 25 MIRSI Operator s Guide CHECK LIST FOR MIRSI SETUP Unpack the camera Be sure the dessicant trap is atta
34. ithsonian Center for Astrophysics 60 Garden Street Cambridge MA 02138 P I Lynne Deutsch Co I Joe Hora Ideutsch cfa harvard edu jhora cfa harvard edu PH 617 384 8209 PH 617 496 7548 FAX 617 495 7490 FAX 617 495 7490 Also John Polizotti is the mechanical engineer who designed the MIRSI telescope interface mounting hardware jpolizotti Ocfa harvard edu PH 617 495 7466 Boston University Institute for Astrophysical Research 725 Commonwealth Avenue Boston MA 02215 Postdoc Joe Adams Grad student Marc Kassis jdadams O bu edu mkassis bu ast bu edu PH 617 353 0285 PH 617 353 0285 FAX 617 353 5704 FAX 617 353 5704 Also Fiscal Administrator Kim Paci has handled MIRSI fiscal accounts kpaci bu edu PH 617 358 0603 FAX 617 353 5704 1 3 Engineering vendor contacts Dewar Cryostat Design and Fabrication Infrared Laboratories Inc 1808 East 17 Street Tucson AZ 85719 6505 http www irlabs com irlabs irlabs com Elliot Solheid Project Manager esolheid irlabs com PH 520 622 7074 FAX 520 623 0765 Kirby Hnat Sr Cryogenics Engineer khnat irlabs com PH 520 622 7074 FAX 520 623 0765 Electronics Box Dr Robert Bob Leach Astronomical Research Cameras Inc Dept of Astronomy MS 1221 San Diego State University San Diego CA 92182 PH 619 594 1406 FAX 619 594 7454 leach mintaka sdsu edu Detector Issues Dr Steve Solomon Raytheon Consultant Acumen Consult
35. jects MIRSI s capabilities span broad and narrow band imaging 2 26 um imaging at a selectable wavelength with a circular variable filter CVF 7 14 um and grism spectroscopy 10 and 20 um The camera operates within a vacuum chamber on a plate that is cooled to liquid helium temperatures using a 2 stage cryostat The first stage is cooled using liquid nitrogen For technical specifications of the instrument and its capabilities see Deutsch et al in Astronomical Telescopes and Instrumentation 2002 SPIE in press or view the AAS poster by Deutsch et al 2001 both papers are available on the MIRSI web site at http mirador bu edu mirsi The primary purpose of this manual is to document the steps required to operate MIRSI in the lab and at the telescope As a visiting instrument at the IRTF MIRSI requires transport to and from the Mauna Kea summit so the current contact information and packing lists that should help facilitate the shipping ordeal have been included A brief troubleshooting guide documents a few bugs in MIRSI that are persistent and not necessarily understood but usually predictable and easy to fix For a discussion of the principles of mid infrared observing and for lists of IR standard stars for flux calibration and other references see the MIRAC3 User s Manual W Hoffmann amp J Hora 1999 online at http cfa www harvard edu jhora mirac mrcman pdf 1 2 MIRSI personnel contact info Harvard Sm
36. lly this means the signal is disconnected before it reaches the A D converter the A D converter outputs a railed value for an open input Try powering down the electronics and then reseat the signal cable connectors If the disconnected signal is persistent it must be found by checking the connectivity of the signal chain from the detector pins to the A Ds Only a MIRSI team member should perform this procedure since it can put the array and the rest of the electronics at risk 7 Host software freezes The best way to solve this problem is prevention Overloading the mirsi program with commands while the program is performing a task can lead to paralysis of the program If the program does freeze up try the following in sequential order until one works Press the reset button on the PCI card white button on the PC near fiber optic connectors a few times Power down the Leach box If this is successful at freeing the program exit the program and then power everything up in the usual order f both of the above are unsuccessful power down the Leach box then power down the PC Obviously this poses a risk to both the array and the PC file systems 8 Slow LHe fill and or condensation and frost on transfer line The LHe transfer lines are prone to loss of vacuum in their insulating jackets Pump out the transfer line for a few minutes If the problem persists after pump out such behavior has been known use another transfer line
37. lower gain SFG test 83 7 2 to be sure the array multiplexer is working The SFG will be slightly lower when the array is warm 3 4 Dewar evacuation using vacuum pump The procedure for pumping the dewar down to high vacuum is also described in the IRLabs Boston University manual MIRSI uses a turbo molecular pump backed by a conventional mechanical pump Open the cold shutter e Connect the dewar vacuum valve to the vacuum pump In the lab you can use the NW40 NW25 tee connector to adapt the Edwards vacuum gauge to the typically NW40 pump line Connect the gauge forward of the turbo pump e Leaving the dewar valve closed begin pumping and evacuate the vacuum line usually until the turbo pump is running nearly full speed Slowly open the dewar valve There may be a slight hissing due to evacuation of gas in the dewar depending on whether the dewar was initially under vacuum Very slowly continue to open the valve in small steps When hissing stops usually after several minutes open the valve fully and continue pumping overnight or least several hours if the dewar was initially under a good vacuum When the dewar reaches sufficiently low pressure 10 to 10 Torr first close the dewar valve then turn the pump off After the pump winds down vent the pump line and disconnect the pump line from the dewar valve Attach the NW 40 safety cap blank to the mouth of the dewar valve 19 Close the cold shutter then di
38. n ended small bread board bread board wire MIRAC User s Manual mount drawings wiring diagrams JFET box clock amp signal cables temp amp motor cable motor control boards chop driver board electronics box amp connectors dewar connectors Case 6 90 Ibs mount plate packed with foam Case 7 40 Ibs LHe transfer lines 2 foil tape duct tape packing tape Extra dewar hardware 8 32 cap screws 17 4 40 cap screws 2 56 cap screws 4 40 flat head screws 316 178 plastic washers for fill ports NW25 vacuum connector to evacuation valve wire wrap wire coax wire 26 AWG spool red black wire 26AWG spools assorted resistors and caps spare J500 JFETS anti static wrist straps w clips gender benders 9 amp 25 pin extra null modems plastic mil spec connector covers fiber optic connector covers 2 5 Suggested shipping crate labels and orientation markers Here are some labels that have been attached to the MIRSI shipping crates 13 CASE I CASE 2 CASE 4 CASE 5 CASE 7 CASE 8 7 THIS SIDE UP 3 SETTING UP MIRSI 3 1 Unpacking and inspection MIRSI should be unpacked and inspected upon the observing team s arrival Open the crates and look for any possible damage Lay components out neatly on the tables in the visiting instrument room If there is any damage notify the present senior person In particular unpa
39. occurred try running the Observing Setup a couple of times See the troubleshooting guide for tricks to make it work if the problem persists REASON The electronics will sometimes boot in an unusual state which requires time for the DSPs to reset 9 Open the Observing Parameters window e Click on the Observing button e Select Home All Wheels 26 Press the Move button The Move button should morph into Stop When the wheels have reached their home positions the Move button will appear again Once the wheels are homed they do not need to be homed again unless the motor control box loses power or the wheel position becomes incorrect for some reason Choose an initial filter and Press the Move button to rotate the wheels 10 From the Observing Parameters window Select before Power On Select Camera Power On Select appropriate observing parameters and press the Apply button 11 Poweron the detector Select Set Detector Voltages from the Setup menu Answer Yes to the warning if the camera is cold 4 K This option sets the correct voltages from the the Bias and Clock Voltages window WARNING Do not apply these voltages when the camera is warm gt 15K Doing so will induce large currents through the detectors and could damage them VCASUC 3 5 VDETGRV 15 4 0 HIGH VGATE Sus LOW Note These voltages require reapplication after each time the camera
40. ole pattern and orientation direction Verify which IRTF cables will be available to link the camera system in the dome to the control room such as fiber optic cable 150 length w ST connectors BNC cable and serial cable 150 length Expect to bring these cables to IRTF in any case as backups 1 months ahead of run Determine cryogen quantities that will be used Fill out Observing Requirements Form Check that a Gaspro account exists to pay for cryogens e Notify Lars of the cryogen plan so that he can obtain the LN for the run and anticipate LHe delivery by Gaspro 10 days ahead of run Order LHe from Gaspro for delivery presumably for delivery on the Wednesday before initial cooldown Pack MIRSI cases and determine their weights should be similar to previous weights in the past Label cases and attach a copy of the airbill on each case Ship MIRSI to the IfA office in Hilo Attn George Koenig NOTE The Fedex heavyweight division does not deliver to Hilo only Honolulu Alternate carriers e g Aloha Airlines Cargo are available to deliver shipments from Honolulu to Hilo Allow several days for the IRTF staff to bring the MIRSI equipment up to the visiting instrument room on the summit few days ahead of run Plan to arrive at Hale Pohaku a few days in advance of the run in order to become acclimated to the altitude and to unpack pre cool and setup MIRSI on the telescope The camera setup proced
41. or currents off by pressing the INIT button in the host software 7 Restart Temperature Log if inactive 8 Update UT date labelled data directories if necessary 9 Set UT date run xclock digital update 1 and update using UNIX date command as root 10 Select Observing Setup Power on Set detector voltages in this order 11 Take a few images If a few channels are bad see the Troubleshooting Guide Shutdown Camera power off from host software 2 Leach box power supply off 3 Leave MIRSI program up and keep temperature log active 4 Attach dessicant trap window cover 5 Close cold shutter 6 Measure LHe level in storage dewar amp determine the time for the next fill 7 Fill the dewar cryogen reservoirs as necessary 8 Measure storage LHe level again record results in cryo log 9 Backup data onto tape and or remote machine MIRSI Operator s Guide MIRSI TROUBLESHOOTING GUIDE The MIRSI system sometimes exhibits a few strange problems that require on the fly adjustments to the system The solutions to some of the problems are often superstitious in nature less than 100 guarantee that they will work but seem to have worked in the past for some known or unknown reason 1 No power on indicating LED lights illuminated on the rear of the Leach box and PCI board Power down the Leach box and reseat the Leach power cable connectors at both ends 2 Host software issues fail warnings during application of controller r
42. port ORF html LHe orders and delivery Gaspro Hilo Mailing address P O Box 30707 Honolulu HI 96820 0707 2 2 Cryogens at IRTF The MIRSI team is responsible for obtaining the appropriate amount of cryogens at the IRTF summit The expected amount of cryogen use should be determined well in advance of the run and entered into the Observing Requirements Form In addition contact Lars Bergknut directly and let him know of MIRSI s cryogens plan IRTF will provide LN5 but the MIRSI team must specify the amount The MIRSI team is responsible for ordering and scheduling the delivery of LHe to the summit Place LHe orders directly with Gaspro Hilo 808 935 3341 at least 10 days in advance because LHe is obtained from the mainland and have them deliver it to the on the summit of Mauna Kea Currently Gaspro delivers to the summit on Wednesdays The IRTF staff can pickup LHe on other days but Gaspro delivery is usually preferred Also expect to receive only 8096 of the nominal LHe quantity due to boil off during transport The storage boil off rate on the mountain is approximately 2 liters per day Note Fiscal Administrator Kim Paci BU has set up a BU account with Gaspro If another account will be used to pay for cryogens it will have to be created 2 3 Timescale guidelines 3 months ahead of run Contact Lars Bergknut to Discuss the instrument interface Lars may request a drawing of the MIRSI mount plate with the bolt h
43. port to a null modem C attached to output port C on the DATAPROBE breakout box Connect the 8 line brown serial line between the controller s serial I O port to a null modem B attached to output port B on the DATAPROBE breakout box Power on the controller and monitor and verify that the sensors are reading the expected temperatures 3 0 2 Operation of temperature controller A Lakeshore temperature controller reads the temperature of the sensor on the rear of the cold finger The controller also has a 2 pin current output which is connected to a heater resistor on the rear of the cold finger The controller allows closed loop temperature control using the sensor and the heater or can simply be used as an open loop temperature sensor To use the closed loop mode select Set Point enter the desired temperature and press Enter Then press Heater Low or Heater High For open loop mode press Heater Off MIRSI currently operates in the open loop mode so the heater power is usually off See the Lakeshore 321 User s Manual for further information 3 9 3 Operation of temperature monitor A sensor temperature reading is selected by manually cycling through the eight available channels on the monitor using the CHANNEL button Currently the channels utilized are 1 Detector fanout board rear side 2 77 K shield 3 Floating shield See the Lakeshore 208 User s Manual for further information 3 9 4 Temperature log The host software con
44. rray by deselecting Camera power on From a shell tool or xterm type cd home camera software SOURCE choptest custom Using your favorite text editor edit the file waveforms asm by changing the parameters OFF O 15 e g the channel offsets should read something like OFF 0 DC 0c0000 OFF 1 DC 0c4100 OFF 2 DC 0c8200 OFF 3 DC 0cc300 OFF 4 DC 1c0400 MIRSI Operator s Guide OFF 5 DC 1c4500 OFF 6 DC 1c8600 OFF 7 DC 1cc700 OFF 8 DC 2c0800 OFF 9 DC 2c4900 OFF 10 DC 2c8A00 OFF 11 DC 2ccB00 OFF 12 DC 3c0C00 OFF_13 DC 3c4D00 OFF 14 DC 3c8E00 OFF 15 DC 3ccF00 Save the file then from the window type tim The timing file should compile Reset the controller and and download the new timing file Follow the usual steps to power up the array Restore the offset levels in waveforms asm to the usual values last three digits of OFF 0 etc are usually 500 Power down reset reload and power up again There is no guarantee that these tricks will work at all 5 Chop and or nod differenced images exhibit a noise pattern that affects faint signals The bad news is the noise is persistent and difficult to remove for extended sources over the whole array The good news is for point sources the noise can be filtered by e g subtracting the median level of the set of pixels that are in the same location in every channel 6 One or more channels reads a railed ADU value of 65535 Usua
45. sengage the pivot shaft 3 5 Cooldown The procedure for cooling the dewar is also described in the IRLabs manual for the Boston University dewar When observing fill MIRSI with LN once per day at the end of the night Fill with LHe every 36 hours if possible otherwise fill with LHe at the end of each night 3 5 Pre cool e First connect the LN storage dewar to the LN reservoir using a latex type hose and the IRLabs fill tube Be sure the reservoir can vent gas without obstruction Then slowly begin LN flow into the reservoir Once liquid begins collecting it should take 15 20 minutes to fill the reservoir assuming the storage dewar pressure is at the nominal 22 psi a smaller storage dewar at lower pressure will take longer e Repeat for the LHe reservoir using LN This reservoir takes 30 60 minutes to fill e After a few hours top off the LN reservoir Attach boil off hoses to prevent ice plugs from forming in the fill port necks Allow the dewar to cool to 77 K overnight or if pressed for time at least 6 hours 3 5 2 LHe cooldown When pre cool is completed measure the level of LHe in the storage dewar Pump out the LHe transfer line if it has not been pumped out recently Blow out the LN in the LHe reservoir Insert gradually a LHe transfer line into the storage dewar After a few minutes liquid should be visible exiting the transfer line Immediately insert the transfer line into the LHe f
46. tains a program that automatically cycles reads and records all temperatures at regular intervals To start this program Boot the host software 24 From the Session menu open the Temperature Control window Select Active The program will automatically create a temperature log for that date or append to an existing one in the ASCII file home camera TemperatureLogs log YYYYMMDD Alternatively log file name can be manually entered 3 10 Telescope At IRTF the day crew will prepare the telescope at the beginning of the run for observations with MIRSI 3 10 1 Secondary mirror The appropriate secondary mirror chopping secondary 35 should be installed and cleaned by the day crew MIRSI should not be mounted on the telescope during this procedure to save cryogens unless necessary 3 10 2 Balance Once MIRSI is cold and mounted with all components and cables secured on the telescope the telescope should be weight balanced by the day crew 25 4 OPERATING MIRSI This procedure contains the steps for taking an exposure once the dewar has been pumped out cooled down and has reached a stable operating temperature 1 Open the cold shutter Remove the window cover 3 Turnon the Leach power supply Two green LED lights in the rear of the Leach box should indicate that the power is on If no LED lights are on see the Troubleshooting Guide 4 Power on the Utility Electronics Temperature monitors an
47. tically backup the desired directories save and gzip the backup file names in a file called home root backup backup YYMMDD gz notify the user by e mail when completed rewind and eject the tape Make a note in the MIRSI lab notebook that the system was backed up onto tape identify tape by A B date or whatever MIRSI Operator s Guide Electronics Box to boards wiring Co Adder Clock Driver 1 Controller box bd 0 bd 1 bd 2 bd 3 Top Plate DB 9 Male gt DB 37 M gt 20 Output 1 2 1 Coax shield 1 1 21 Output 2 7 2 Coax shield 2 6 22 Output 3 9 3 Coax shield 3 8 23 Output 4 4 4 Coax shield 4 3 24 Output 5 2 5 Coax shield 5 1 25 Output 6 7 6 Coax shield 6 6 26 Output 7 9 7 Coax shield 7 8 27 Output 8 4 8 Coax shield 8 3 28 Output 9 2 9 Coax shield 9 1 29 Output 10 7 10 Coax shield 10 6 30 Output 11 9 11 Coax shield 11 8 31 Output 12 4 12 Coax shield 12 3 32 Output 13 2 13 Coax shield 13 1 33 Output 14 T 14 Coax shield 14 6 34 Output 15 9 15 Coax shield 15 8 35 Output 16 4 16 Coax shield 16 3 36 amp 37 Grounds 55 5 5 18 Offsets channels 9 16 36 not 19 Offsets channels 9 16 37 attached MIRSI Operator s Guide CONTROLLER BOX DB 50 Female IMUX 2 VGG2 3 VGG3 4 VGG4 5 VDETGRV 6 VDETGRNG 7 VNEG 8 VCASUC 18 VRSTUC 19 VSHPCHG 20 VSH 21 VDDD 22 VDD4 23 VSSD 24 VSS1 25 VSS2 34 VPW 35 VCLOUT 36 VCL
48. to a doughnut or ring shape as seen by the camera Have the telescope operator adjust the tilt of the secondary mirror until the ring appears uniform in brightness 5 1 5 Target lists Target information is gathered by the host program and entered into the image FITS headers Currently the host program does not yet send coordinates to the telescope control system The host program can upload a file containing a list of targets or coordinates This feature speeds up the process of updated the target information into the FITS header A target file requires the form Object RA DEC Epoch e g note the underscore in the name string Orion nebula 05 05 50 05 30 29 2000 To load the target list first from the Session menu select Target amp Observer Info and then load the file Alternatively an observer can enter the target information manually and optionally add the target to the current list 29 5 1 6 Standard stars For point source flux calibration the MIRSI team typically uses bright targets from a list of mid infrared standard stars in the MIRAC3 User s Manual W Hoffmann amp J Hora 1999 5 1 7 Telescope offsets and dither mosaic procedures Telescope offsets can be sent from the MIRSI host software to the telescope control system Under the Session menu open the Offset Commands window Manually enter the offsets in arcsec and press the Send button To load an automated 4 step dither pattern choose tiny
49. troller Leach board schematics A D FIFO data sheets Lakeshore 208 amp 321 manuals OMS control board manual Voodoo software manual FITS manual Tools hex key sets 2 hex ball driver set long 9 64 hex ball driver jewelry screw amp socket drivers set wire cutters Ig amp sm needle nose pliers Ig amp sm adjustable wrench calipers tape measure electric drill wire stripping tool wire strippers crimping tool exacto knife amp blades razor retaining ring pliers phillips amp flat head drill bit set drill bit set long amp short tweezers wire wrap stripping tool IC extraction tool dental tools mechanical fingers Miscellaneous small flashlight latex gloves Kim wipes Polystyrene calibration cards wood screws 12 Vacuum amp Cryo vac gauge optional vac gauge meter optional 8 line cable for meter optional ambient temp sensor wire amp pins NWA0 25 tee connector NW40 to 25 cone adapter NWAO to 25 straight adapter NW23 to nozzle adapter NW25 clamps 4 NW40 clamps 2 NW25 blanks 4 NW40 blank 1 on dewar 1 extra NW25 40 plastic covers NW25 40 O rings 2 4 each pipe thread to thin nozzle adapter pipe thread to wide nozzle adapters teflon tape transfer line O ring fittings hose clamps extra latex tubing Electrical electrical tape DMM DMM wires DMM leads needle tipped DMM leads aligator tipped DMM wires socket amp pi
50. tter then disengage the pivot shaft During pump out and or pre cool the day crew can install the appropriate secondary mirror for MIRSI chopping secondary Begin pre cooling with LN Allow for pre cooling overnight if possible After pre cool blow the LN out of the LHe reservoir Immediately begin LHe fill Attach the mount bipod legs to the mount telescope interface plate Attach the mount telescope interface plate to the MIM Attach the dewar to the mount bipods assuming LHe fill is completed Attach the flow meter to the LHe fill port and mount to the dewar appropriately Mount the leach power supply box onto the MIM Rack mount the peripheral components onto the MIM motor control box temperature monitors controller chop drive box Connect power and signal cables to all components Stress relieve the cables Connect fiber optic cables to the camera electronics and the chop drive box Stress relieve carefully Set up the MIRSI host computer and connect to the network if not done already Boot the host software and verify that the temperature filter wheel motors and camera electronics are functioning properly Balance the telescope MIRSI Operator s Guide MIRSI NIGHTLY OBSERVING CHECK LISTS General Startup Be sure camera and cables will be free of obstruction during telescope motion 2 Open cold shutter 3 Turn on Leach box power 4 Remove dessicant trap 5 Start host software if not already running 6 Check mot
51. ure should be coordinated through Lars so that MIRSI does not interfere with other IRTF projects 2 4 Packing inventory and weight distribution This has been a typical configuration for the MIRSI equipment Of course the location of small miscellaneous items will have to be adjusted to the distribution of available space Weights will vary accordingly Case 1 185 Ibs dewar w NW40 on vacuum valve and grounding caps on all mil spec connectors snout rear electronics support bracket interface plate bolted to dewar window cover Case 2 160 Ibs SUN CPU case motor control box Leach power supply Leach electronics box w 50 pin open connector and 37 pin grounding connectors attached temperature controller chop drive box chop drive power cable Case 3 120 lbs computer monitor temperature monitor keyboard mouse DATAPROBE box DATAPROBE box power cable null modems 4 or more extra 8 line serial cable spool 4mm data storage tapes lt 12 GB 10 Case 4 80 lbs JFET box packed with foam power cables 9 or more suggest label w green tape as MIRSI ID tag latex hosing small and large diameter small stainless steel Funnel with fill tube 25 pin serial cables 25 length 2 flow meter packed in bubble wrap cryo gauge IRLabs fill tube w vent port extender board packed in cardboard box portable socket set small socket ratchet socket driver long and short ratc
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