tuning_the_s800_xdt
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tuning_the_s800_xdt [2015/10/26 14:08] pereira [Reaction Setting] |
tuning_the_s800_xdt [2015/10/27 16:43] pereira [FP scintillator setup] |
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| Line 18: | Line 18: | ||
| * Expected " | * Expected " | ||
| - | * Ensure that CRAD04 | + | * Ensure that CRAD04 is enabled with a rate limit of **20 kHz** (CRAD04 looks at E1 up FP scintillator) |
| * Remember: S800 FP rate limit is **6 kHz** | * Remember: S800 FP rate limit is **6 kHz** | ||
| Line 55: | Line 55: | ||
| * Adjust MCFD threshold: | * Adjust MCFD threshold: | ||
| - | * Open configuration file **MCFD16.tcl** in **/user/s800/ | + | * Using the [[s800 daq tools# |
| * The OBJ signal feeding this module is not patched out to data U6 | * The OBJ signal feeding this module is not patched out to data U6 | ||
| - | * The OBJ signal from MCFD-16 module goes to the Mesytec | + | * The OBJ signal from MCFD module goes to the Mesytec |
| * Make sure that the threshold of the XFP MCFD channel is reasonable. Rates in scaler channels XFP.Scint and XFP.MCFD.Scint should be comparable | * Make sure that the threshold of the XFP MCFD channel is reasonable. Rates in scaler channels XFP.Scint and XFP.MCFD.Scint should be comparable | ||
| * Adjust MCFD OBJ threshold looking at scalers. The ratio of OBJ to XFP scaler rates (channels OBJ.MCFD.Scint and XFP.MCFD.Scint) should reflect the transmission of the cocktail beam | * Adjust MCFD OBJ threshold looking at scalers. The ratio of OBJ to XFP scaler rates (channels OBJ.MCFD.Scint and XFP.MCFD.Scint) should reflect the transmission of the cocktail beam | ||
| Line 74: | Line 74: | ||
| * End and Begin **[[s800 daq tools#Run Control Window|ReadoutGUI]]** to assert new trigger condition | * End and Begin **[[s800 daq tools#Run Control Window|ReadoutGUI]]** to assert new trigger condition | ||
| - | * Select **[[s800 SpecTcl|Spectcl]]** window **S800_SCINT.win** | + | * Select **[[s800 SpecTcl|Spectcl]]** window **S800_SCINT.win** in directory **/ |
| * Adjust **[[hv bias|bias]]** looking at 2D spectra **e1.deup_e1.dedown** (showing the parameters s800.fp.e1.de_down vs. s800.fp.e1.de_up) for the FP E1 scintillator | * Adjust **[[hv bias|bias]]** looking at 2D spectra **e1.deup_e1.dedown** (showing the parameters s800.fp.e1.de_down vs. s800.fp.e1.de_up) for the FP E1 scintillator | ||
| Line 155: | Line 155: | ||
| * They correspond to the non-dispersive position of the beam in the CRDCs. | * They correspond to the non-dispersive position of the beam in the CRDCs. | ||
| - | {{: | + | {{: |
| Line 214: | Line 214: | ||
| ==== Analysis line classic PPAC setup (Focus optics only) ==== | ==== Analysis line classic PPAC setup (Focus optics only) ==== | ||
| + | **THIS SECTION IS STILL IN PROGRESS** | ||
| * " | * " | ||
| Line 237: | Line 238: | ||
| ==== Setting Optimization ==== | ==== Setting Optimization ==== | ||
| - | |||
| - | === Focused optics === | ||
| * Expectations for A1900 FP to S800 FP transmission | * Expectations for A1900 FP to S800 FP transmission | ||
| Line 248: | Line 247: | ||
| * Want to balance losses between S800 analysis line and Transfer Hall (the S800 analysis line is typically slightly worse) | * Want to balance losses between S800 analysis line and Transfer Hall (the S800 analysis line is typically slightly worse) | ||
| * Best diagnostic is scalers from S800 FP, object scintillator and XF scintillator | * Best diagnostic is scalers from S800 FP, object scintillator and XF scintillator | ||
| - | * Tweak y-quads (while watching scalers) in front of dipole gaps (this works both for Transfer Hall and analysis line); choose elements that have biggest effect with smallest ratio change | + | * Using the knob box and the NCS application **QtKM** (file **BLSetup_A1900.gkm**), |
| * Document optimized transmission with another run to disk to measure rate of fragment of interest at S800 FP | * Document optimized transmission with another run to disk to measure rate of fragment of interest at S800 FP | ||
| Line 256: | Line 255: | ||
| - | |||
| - | ==== Coincidences ==== | ||
| - | |||
| - | * Overview | ||
| - | * Most experiments at the S800 involve setting up an auxiliary detector system (e.g. SeGA, HiRA, etc) to be used in coincidence with the standard detectors of the S800. | ||
| - | * The auxiliary detector provides a secondary trigger that is fed into the S800 trigger system | ||
| - | * A key part of setting up the S800 for such experiments is getting proper timing setup between the S800 and any auxiliary detectors | ||
| - | * For cases where the Secondary detector has a slow response relative to the S800, the coincidence timing must be reset to the S800 timing by delaying the S800 trigger using the third gate and delay generator on the trigger GUI | ||
| - | * A typical S800 delay for SeGA is 450 ns | ||
| - | * Probably smaller typical S800 delay needed for HiRA | ||
| - | * An example of experiments where auxiliary detectors are not used and, thus, setting up coincidence timing is not an issue are the experiments with tritons run by the charge exchange group | ||
| - | * It is not clear whether coincidence setup gets logged as “XDT” or “EXR” | ||
| - | |||
| - | * Choice of setting to be used for coincidence timing setup | ||
| - | * The reaction of interest for the experiment can be used to setup coincidences only if the rate of coincidences is high enough | ||
| - | * Sometime the pilot beam is used for setting up the coincidence timing in cases where the intensity of the secondary beam is too small | ||
| - | * Example: | ||
| - | |||
| - | * Setup | ||
| - | * Coincidence signals are usually visible on scope without running scope in acquire mode | ||
| - | * Adjust the width of the early signal (S800 or secondary) should be wide enough to catch coincidences with the late signal (width of late signal is not critical) | ||
| - | * Readjust TDC delays based on changes made to S800 trigger delay | ||
| - | * Experimenters will need to adjust their delays based on delay made to S800 trigger | ||
| - | * Have experimenters record a run with coincidences on their account | ||
| - | * S800 trigger TDC channel should show a peak (which corresponds to coincidences) | ||
| - | * " | ||
| - | * This check is required for verification in cases of low beam intensity (e.g. 1000 pps) | ||
| - | * Length of run required is typically about 10-15 minutes | ||
| - | * To be resolved: | ||
| - | |||
| - | * Sample timing for running S800 with SeGA | ||
| - | * SeGA trigger is late with respect to S800 trigger | ||
| - | * The figure below represents a timing schematic to show how to | ||
| - | * Setup of the S800 trigger to recover timing needed for proper functioning of S800 FP detectors | ||
| - | * Set up the coincidence trigger | ||
| - | * See: http:// | ||
| - | |||
| - | {{: | ||
| - | |||
| - | * A double peak structure will appear in the TDC for the S800 trigger between the coincidence events and the singles events (see figure below); the groups are separated by 25 ns because of the delay introduced by the downscaler used for the singles | ||
| - | |||
| - | {{: | ||
| - | |||
| - | |||
| - | |||
| - | ===== Follow-up ===== | ||
| - | |||
| - | * Before leaving beam with experimenters | ||
| - | * Set up current trip points on Linux HV controls | ||
| - | * Values used for K-48 | ||
| - | * 5 for CRDC and Ion Chamber anodes and intermediate image ppacs | ||
| - | * 50 for CRDC drifts | ||
| - | * 80 for IC drift | ||
| - | * Ensure alarms are running | ||
| - | * Make sure Linux HV GUI alarms are enabled | ||
| - | * Make sure threshold on isobutane level is set up (not currently connected to alarms because they give too many false alarms when communication is lost) | ||
| - | * All logs are being recorded | ||
| - | * There is no log file for biases controlled by Labview | ||
| - | * Linux HV | ||
| - | * LabView gas handling system | ||
| - | * Note in logbook | ||
| - | * Scintillator biases | ||
| - | * IC gate biases | ||
| - | * Post reference printouts for experimenters | ||
| - | * HV status: a snapshot of HV GUI | ||
| - | * Gas handling system status: a snapshot of LabView window | ||
| - | |||
| - | * Create window configuration with summing regions to make it easier for experimenters to track efficiency/ | ||
| - | |||
| - | * Setting up coincidences for additional reaction settings in an experiment | ||
| - | * Do not need to redo coincidence settup if secondary beam does not change | ||
| - | * Might need to redo coincidence setup if secondary beam changes drastically | ||
| - | |||
| - | * To watch during experiment | ||
| - | * Look for isobutene running out – messes up data over several hours | ||
| - | |||
| - | * Implementing dE- or TOF-based corrections is part of EXR | ||
| - | |||
| - | More detail needed | ||
| - | Minimum rates required for coincidence setup | ||
| - | Selection of appropriate substitute reactions for coincidence setup | ||
| - | How to feel comfortable that there will not be a problem with FP detector gases running out | ||
| - | Starting alarms | ||
| - | Starting logging | ||
| - | ====== Dispersion Matching | + | ====== Dispersion Matching |
| In the dispersion-matching optics, the S800 focal point is achromatic, i.e. the position of the beam in the dispersive direction does not depend on the momentum. As a consequence, | In the dispersion-matching optics, the S800 focal point is achromatic, i.e. the position of the beam in the dispersive direction does not depend on the momentum. As a consequence, | ||
| Line 371: | Line 286: | ||
| | | ||
| * The leftmost peak corresponds to reactions with H. The central peak are reaction with C. The goal of the tweak is to make these peaks as narrow as possible | * The leftmost peak corresponds to reactions with H. The central peak are reaction with C. The goal of the tweak is to make these peaks as narrow as possible | ||
| - | * Open the NCS application **QtKM** in the Applications Menu. Open file **BLSetup_A1900.gkm**. The magnetic elements that are typically tweaked with the knob box seating | + | * Open the NCS application **QtKM** in the Applications Menu. Open file **BLSetup_A1900.gkm**. The magnetic elements that are typically tweaked with the knob box sitting |
| | | ||
| * The two figures below show the spectrum **CRDC1.XG!FOI-AFP-BFP** before (top) and after (bottom) the dispersion-matching tuning for a typical experiment. Be aware that the width given by SpecTcl for the selected peak is not too reliable. It is more convenient to do a real gaussian fit. Unfortunatelly this is not an option included in the current version of SpecTcl. That's why some device physicists prefer SpecTk for this type of tuning | * The two figures below show the spectrum **CRDC1.XG!FOI-AFP-BFP** before (top) and after (bottom) the dispersion-matching tuning for a typical experiment. Be aware that the width given by SpecTcl for the selected peak is not too reliable. It is more convenient to do a real gaussian fit. Unfortunatelly this is not an option included in the current version of SpecTcl. That's why some device physicists prefer SpecTk for this type of tuning | ||
| Line 395: | Line 310: | ||
| * Reaction setting to FP | * Reaction setting to FP | ||
| * Start with Attenuator setting of unreacted beam and step up in intensity | * Start with Attenuator setting of unreacted beam and step up in intensity | ||
| - | * Set up beam blocker, | + | * If necessary, set up beam blocker |
| + | * Click on label **I255 Slits** in the S3 page of Barney | ||
| + | * Expected " | ||
| * Expect to see unreacted beam if reaction setting is within +/- 3% of unreacted beam setting | * Expect to see unreacted beam if reaction setting is within +/- 3% of unreacted beam setting | ||
| * Should have to move only one of the two blockers unless charge states are present | * Should have to move only one of the two blockers unless charge states are present | ||
| - | * A graphic tool is available to help (not yet calibrated) | ||
| * Try to cut only as much as necessary; depends on | * Try to cut only as much as necessary; depends on | ||
| * What rate limits allow | * What rate limits allow | ||
| * What experimenters want (e.g., if they want singles, the cut has to be more restrictive to limit acquisition deadtime) | * What experimenters want (e.g., if they want singles, the cut has to be more restrictive to limit acquisition deadtime) | ||
| * Move blocker, decrease attenuator, repeat | * Move blocker, decrease attenuator, repeat | ||
| + | |||
| + | |||
| + | |||
| + | |||
| + | |||
| + | ===== Coincidences ===== | ||
| + | |||
| + | * Overview | ||
| + | * Most experiments at the S800 involve setting up an auxiliary detector system (e.g. SeGA, HiRA, etc) to be used in coincidence with the standard detectors of the S800. | ||
| + | * The auxiliary detector provides a secondary trigger that is fed into the S800 trigger system | ||
| + | * A key part of setting up the S800 for such experiments is getting proper timing setup between the S800 and any auxiliary detectors | ||
| + | * For cases where the Secondary detector has a slow response relative to the S800, the coincidence timing must be reset to the S800 timing by delaying the S800 trigger using the third gate and delay generator on the trigger GUI | ||
| + | * A typical S800 delay for SeGA is 450 ns | ||
| + | * Probably smaller typical S800 delay needed for HiRA | ||
| + | * An example of experiments where auxiliary detectors are not used and, thus, setting up coincidence timing is not an issue are the experiments with tritons run by the charge exchange group | ||
| + | |||
| + | * Choice of setting to be used for coincidence timing setup | ||
| + | * The reaction of interest for the experiment can be used to setup coincidences only if the rate of coincidences is high enough | ||
| + | * Sometime the pilot beam is used for setting up the coincidence timing in cases where the intensity of the secondary beam is too small | ||
| + | * Example: | ||
| + | |||
| + | * Setup | ||
| + | * Coincidence signals are usually visible on scope without running scope in acquire mode | ||
| + | * Adjust the width of the early signal (S800 or secondary) should be wide enough to catch coincidences with the late signal (width of late signal is not critical) | ||
| + | * Readjust TDC delays based on changes made to S800 trigger delay | ||
| + | * Experimenters will need to adjust their delays based on delay made to S800 trigger | ||
| + | * Have experimenters record a run with coincidences on their account | ||
| + | * S800 trigger TDC channel should show a peak (which corresponds to coincidences) | ||
| + | * " | ||
| + | * This check is required for verification in cases of low beam intensity (e.g. 1000 pps) | ||
| + | * Length of run required is typically about 10-15 minutes | ||
| + | * To be resolved: | ||
| + | |||
| + | * Sample timing for running S800 with SeGA | ||
| + | * SeGA trigger is late with respect to S800 trigger | ||
| + | * The figure below represents a timing schematic to show how to | ||
| + | * Setup of the S800 trigger to recover timing needed for proper functioning of S800 FP detectors | ||
| + | * Set up the coincidence trigger | ||
| + | * See: http:// | ||
| + | |||
| + | {{: | ||
| + | |||
| + | * A double peak structure will appear in the TDC for the S800 trigger between the coincidence events and the singles events (see figure below); the groups are separated by 25 ns because of the delay introduced by the downscaler used for the singles | ||
| + | |||
| + | {{: | ||
| + | |||
| + | |||
| + | |||
| + | |||
tuning_the_s800_xdt.txt · Last modified: 2023/09/22 15:15 by swartzj
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