tuning_the_s800_xdt
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tuning_the_s800_xdt [2015/10/26 12:18] pereira [Timing setup] |
tuning_the_s800_xdt [2017/04/08 13:43] pereira [Dispersion Matching Mode] |
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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 68: | Line 68: | ||
| * Set trigger to “s800 trigger” | * Set trigger to “s800 trigger” | ||
| - | * Ensure that the **[[s800 daq tools# | + | * Ensure that the **[[s800 daq tools# |
| * Under trigger tab select **s800 trigger** (which is E1 up by definition) | * Under trigger tab select **s800 trigger** (which is E1 up by definition) | ||
| * Deselect experiment trigger | * Deselect experiment trigger | ||
| 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** |
| * 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 94: | Line 95: | ||
| - | * Select **[[s800 SpecTcl|Spectcl]]** window **S800_IC.win** | + | * Select **[[s800 SpecTcl|Spectcl]]** window **S800_IC.win** |
| * Adjust pad gains | * Adjust pad gains | ||
| Line 155: | Line 156: | ||
| * 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 162: | Line 163: | ||
| - | * Select SpecTcl window S800_TOF.win | + | * Select SpecTcl window |
| - | * Make sure that the time range of spectra | + | * The three columns correspond to the **RF-FP** ToF (left), **OBJ-FP** (center), and **XFP-FP** (right) |
| - | + | * The first (top) row corresponds to the Phillips TDC | |
| + | * The second row corresponds to the MTDC with all the hits included. Note that in a unreacted-beam setting, | ||
| + | * The third row corresponds to the MTDC with only the first hit | ||
| + | * The fourth row corresponds to the ORTEC TACs. Note that there is not **RF-FP TAC** | ||
| + | * The two spectra in the fifth row corresponds to the MTDC summary spectra | ||
| + | * An empty ToF spectrum means that either the delays are not right (and need to be adjusted) or the spectrum range is too narrow | ||
| + | * The MTDC delays should never need to be adjusted because the matching window is sufficiently wide (around 4000 ns) | ||
| {{: | {{: | ||
| - | * Although | + | * Due to the multi-hit capability of the MTDC, we need to select |
| - | * Before going to the ToF modules, the OBJ and XFP signals are sent to a CANBERRA CFD 454 CFD in data U6 from the data-U6 patch panel (OBJ: patch panel #54, XFP: patch panel #1). (The exception is the OBJ signal into the MTDC) | + | * Use the spectra **TOF.MTDC_RF**, **TOF.MTDC_OBJ**, and **TOF.MTDC_XFP** |
| - | * MTDC: | + | * Using the cursor mouse, check the lower and higher limits defining the region |
| - | * Before getting into the MTDC, the OBJ, XFP, and E1 up signals | + | * Go to the **Variables** page in SpecTcl GUI and assign the limits |
| - | * The OBJ signal into the MCFD comes directly from the detector via S3 patch panel #94 (i.e., there is no signal to check in data U6) | + | * **s800.fp.vmetdc.mtdc_rflow** |
| - | * The XFP signal into the MCFD module comes from data-U6 patch panel #70, connected to the CANBERRA 454 CFD XFP output | + | * **s800.fp.vmetdc.mtdc_objlow** and **s800.fp.vmetdc.mtdc_objhigh** for OBJ-XFP |
| - | * SpecTcl calculates the OBJ-to-Focal-Plane | + | * **s800.fp.vmetdc.mtdc_xfplow** and **s800.fp.vmetdc.mtdc_xfphigh** for XFP-XFP |
| - | * The MTDC timing signals do not require external delay adjustments because the matching window is sufficiently wide | + | * For each ToF, SpecTcl will search |
| - | | + | |
| - | | + | |
| - | * The XFP **stop** signal to the "XFP-to-Focal-Plane" | + | |
| - | * Phillips TDC: | + | * If necessary, adjust delays: |
| - | * The OBJ output signal from the CANBERRA 454 CFD is delayed | + | * Using the [[S800 DAQ tools# |
| - | * The XFP output signal from the CANBERRA 454 CFD is delayed with the low-noise delay boxes in data-U6, and sent to the TDC via patch panel #66 | + | * Select |
| - | * SpecTcl calculates the OBJ-to-Focal-Plane and XFP-to-Focal-Plane ToFs by substracting | + | * Adjust the TDC delays of OBJ and XFP using the delay boxes connected to the CANBERRA |
| + | * Adjust | ||
| + | * In principle, | ||
| - | * The TDC start is sent from the ULM trigger module. Since the delay of the S800 trigger may be adjusted during XDT, the stop signals (e.g. from OBJ or XFP) will need to be re-adjusted. | ||
| - | | + | |
| - | * There are 4 TDC inspect channels patched to data-U6 that can be assigned using the trigger GUI | + | * Make a gate on spectrum |
| - | * The full range of the TDC is 400 ns | + | * Looking at the ToF spectra gated on " |
| - | | + | * The window file **S800_TOF_EFFICIENCY.win** includes all the spectra needed |
| - | | + | |
| - | * They can be inspected, however using the GUI | + | |
| - | * The TDC delays can only be changed when the run control is stopped; must SAVE settings before starting run control not to overwrite adjustments being made | + | ==== Checking Particle ID and rate at S800 FP ==== |
| - | * Trigger | + | * Select SpecTcl window **S800_PID.win** |
| - | * There are 4 trigger inspect channels patched | + | * The three columns correspond to the PID determined |
| + | * The first (top) row corresponds | ||
| + | * The second row corresponds to PID spectra using the MTDC with __just the first hit included__ | ||
| + | * The third row corresponds to PID spectra using the MTDC including the correct hit corresponding to the good ToF peak (see previous section) | ||
| + | * The fourth row corresponds to PID spectra using the MTDC gated on the " | ||
| + | * The fifth row corresponds to PID spectra using the ORTEC TACs. Note that there is not **RF-FP TAC** | ||
| + | * You might need to adjust the limits of the spectra to get a good resolution | ||
| - | * Examine the timing of each of the selectable listed signals with respect to the “Live Trigger” signal | + | {{: |
| - | * There are 4 TDC inspect channels patched to data-U6 that can be assigned using the trigger GUI | + | |
| - | * The full range of the TDC is 400 ns | + | |
| - | * Set each timing to 200 ns | + | |
| - | * TDCs of last 4 listed signals (including XF and object scintillators) are bypassed with cable delays inside the vault and thus their delays cannot be controlled with the GUI | + | |
| - | * They can be inspected, however using the GUI | + | |
| - | * See [[http:// | + | * Establish PID and measure rate |
| + | * Choose your favorite PID spectrum and determine the blob that corresponds to the unreacted beam (refer to information on setting from A1900 FP). Note: the PID using the first MTDC hit might be missing good events | ||
| + | * Take gates around the fragment of interest | ||
| + | * Measure the beam intensity the appropriate faraday cup | ||
| + | * Take a run on disk | ||
| + | * Measure the beam intensity again and calculate the average value | ||
| + | * In [[s800 SpecTcl|SpecTcl GUI]], click **Attach to File** and select data file **run-xxxx-xx.evt** in directory **/user/s800/stagearea/experiment/runxxxx**, where xxxx stands | ||
| + | * Check the run time and live time from the corresponding scaler file in directory **/ | ||
| + | * Calculate the rate and purity and compare with the value in the A1900 FP to determine the transmission | ||
| - | * The TDC delays can only be changed when the run control is stopped; must SAVE settings before starting run control not to overwrite adjustments being made | ||
| - | * The “S800” trigger is from E1 up signal | ||
| - | * Trigger the scope with the “Live Trigger” signal patched to data-U6 | ||
| - | * There are 4 trigger inspect channels patched to data-U6 that can be assigned using the trigger GUI | ||
| - | * Examine the timing of each of the selectable listed signals with respect to the “Live Trigger” signal | ||
| - | * There are 4 TDC inspect channels patched to data-U6 that can be assigned using the trigger GUI | ||
| - | * The full range of the TDC is 400 ns | ||
| - | * Set each timing to 200 ns | ||
| - | * TDCs of last 4 listed signals (including XF and object scintillators) are bypassed with cable delays inside the vault and thus their delays cannot be controlled with the GUI | ||
| - | * They can be inspected, however using the GUI | ||
| - | * Information | ||
| - | * The signal delays controlled by the GUI (and not by cable delays) are not “pipelined” -– i.e., any new signals that arrive during the delay time of a previous signal are lost and thus deadtime is introduced into the system. | ||
| - | * All of the trigger signals are not pipelined and are thus subject to deadtime | ||
| - | ==== Checking Particle ID and rate at S800 FP ==== | ||
| - | * Establish PID | ||
| - | * Refer to information on setting from A1900 FP | ||
| - | * dE-TOF | ||
| - | * dE signal from Ion Chamber | ||
| - | * TOF from XF or Object scintillator to S800 FP | ||
| - | * Not necessary to implement dE- or TOF-based corrections | ||
| - | * Document rate of fragment of interest with run to disk | ||
| - | * Measure beam current with appropriate Faraday cups | ||
| - | * Timed run | ||
| ==== Analysis line classic PPAC setup (Focus optics only) ==== | ==== Analysis line classic PPAC setup (Focus optics only) ==== | ||
| + | **THIS SECTION IS STILL IN PROGRESS** | ||
| + | |||
| * " | * " | ||
| * Classic PPACs have rate limitations from pileups | * Classic PPACs have rate limitations from pileups | ||
| Line 261: | Line 254: | ||
| * Confirm correlations between dispersive angle at intermediate image and p in FP (e.g., crdc1x). This correlation will be somewhat washed out by straggling in the target; in principle, this should be checked without the target, but the benefit vs. cost in time to remove the target is not worth it. | * Confirm correlations between dispersive angle at intermediate image and p in FP (e.g., crdc1x). This correlation will be somewhat washed out by straggling in the target; in principle, this should be checked without the target, but the benefit vs. cost in time to remove the target is not worth it. | ||
| - | |||
| - | |||
| - | ==== Setup beamline ==== | ||
| - | * Object and XF scintillators and intermediate image PPACs inserted if they will be used | ||
| - | * If Object scintillator will not be used, there is no reason to look at beam on it unless to debug a problem with the transmission | ||
| - | |||
| - | * Set spectrograph Brho for unreacted fragment | ||
| - | |||
| - | ==== Start scalers ==== | ||
| - | * Use s800 account | ||
| - | |||
| - | * Make sure experiment daq is: | ||
| - | * Stopped | ||
| - | * Gone | ||
| - | * Open terminal window (from bottom of mac) | ||
| - | * ssh to spdaq20 | ||
| - | * ps auw | grep Readout | ||
| - | * Does not get restarted | ||
| - | |||
| - | * Under operations folder on mac | ||
| - | * scalers (gives error if no bridge) | ||
| ==== Setting Optimization ==== | ==== Setting Optimization ==== | ||
| - | === Focused optics === | ||
| * Expectations for A1900 FP to S800 FP transmission | * Expectations for A1900 FP to S800 FP transmission | ||
| * 80% or better for mid-Z fragments | * 80% or better for mid-Z fragments | ||
| Line 294: | Line 265: | ||
| * 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 300: | Line 271: | ||
| - | === Matched optics === | ||
| - | * Typically much more time is invested for optimizing optics for matched optics than for focused optics | ||
| - | * One input is optimizing for transmission | ||
| - | * For tritons a scintillator is required at the pivot position since fragments at 5 Tm will not reach S800 FP | ||
| - | * The last two analysis line triplets are used to tweak for the desired optical properties | ||
| - | * Document optimized transmission with another run to disk to measure rate of fragment of interest at S800 FP | ||
| + | ====== Dispersion Matching Mode ====== | ||
| - | ===== Reaction Setting ===== | + | 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, |
| + | |||
| + | Charge-exchange experiments require typically this optics. In some cases, the beam used is < | ||
| + | |||
| + | * Set trigger to “s800 trigger” | ||
| + | * Ensure that the **[[s800 daq tools# | ||
| + | * Under trigger tab select **s800 trigger** (which is E1 up by definition) | ||
| + | * Deselect experiment trigger | ||
| + | * SAVE TO FILE | ||
| + | * Begin a new run on [[#Readout GUI|Readout GUI]] to assert new trigger condition | ||
| + | |||
| + | * Select **[[s800 SpecTcl|Spectcl]]** window **S800_DISPMATCH.win** | ||
| + | | ||
| + | |||
| + | * We need to start checking the spectra showing the correlations between angle and position in both dispersive and non-dispersive directions. We typically use the spectrum **CRDC1.XG_CRDC1.TAC** for the non-dispersive direction, and **S800.FP.TRACK.XFP_TRACK.AFP** for the dispersive direction | ||
| + | | ||
| + | * The parabolas seen in the above spectra correspond to reactions with H in the target. The blurred lines on the right of the parabolas correspond to reaction with C. It is hard to see clearly this lines, so we need to make several gates | ||
| + | * Open spectrum **E1.DE_TOF.RF** and define a gate around < | ||
| + | | ||
| + | * This gate is used to fill spectra **S800.FP.TRACK.XFP_TRACK.AFP!FOI** and **CRDC1.XG_CRDC1.TAC!FOI**. As can be seen in the figures below, this gate " | ||
| + | | ||
| + | * Define rectangular gates in this spectra, making sure that it is narrow enough to select a vertical section of the parabolas, but wide enough to get enough statistics. Call them **afp** (in spectrum **CRDC1.XG_CRDC1.TAC!FOI**) and **bfp** (in spectrum **S800.FP.TRACK.XFP_TRACK.AFP!FOI**). After applying these new gates, the kinematics spectra are very clean | ||
| + | {{: | ||
| + | * The pre-defined gate **allgates** is made by the AND condition of all the gates defined above (**foi**, **afp**, and **bfp**). This gate is used to fill the spectrum **CRDC1.XG!FOI-AFP-BFP**, | ||
| + | | ||
| + | * 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 sitting on the left side of u6pc5 are **I232TA**, **I236TC**, and **I245TC** which can be found on page **S800 BLine+Spectrograph**. Other elements used to improve the focusing in the object point, and the transmission are **I172QA** and **I174QB**. The goal of the dispersion-matching tuning is to find a compromise between transmission and resolution. | ||
| + | | ||
| + | * 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 | ||
| + | {{: | ||
| + | |||
| + | |||
| + | ====== Reaction Setting | ||
| + | |||
| + | ===== Setting up Reaction Settings ====== | ||
| - | ==== Setting up Reaction Settings ==== | ||
| * Calculating reaction setting | * Calculating reaction setting | ||
| * Center unreacted beam at S800 FP | * Center unreacted beam at S800 FP | ||
| Line 329: | Line 328: | ||
| * 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 | ||
| Line 338: | Line 338: | ||
| * Move blocker, decrease attenuator, repeat | * Move blocker, decrease attenuator, repeat | ||
| - | ==== Coincidences ==== | + | * If necessary, do the ToF corrections to improve the PID resolution (instructions [[During experiments# |
| + | |||
| + | |||
| + | |||
| + | |||
| + | |||
| + | ===== Coincidences ===== | ||
| * Overview | * 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. | * 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. | ||
| Line 347: | Line 354: | ||
| * Probably smaller typical S800 delay needed for HiRA | * 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 | * 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 | * 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 | * The reaction of interest for the experiment can be used to setup coincidences only if the rate of coincidences is high enough | ||
| Line 381: | Line 387: | ||
| - | ===== 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 tuning ====== | ||
| - | 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, | ||
| - | |||
| - | Charge-exchange experiments require typically this optics. In some cases, the beam used is < | ||
| - | |||
| - | * Set trigger to “s800 trigger” | ||
| - | * Ensure that the **[[s800 daq tools# | ||
| - | * Under trigger tab select **s800 trigger** (which is E1 up by definition) | ||
| - | * Deselect experiment trigger | ||
| - | * SAVE TO FILE | ||
| - | * Stop and start **[[s800 daq tools#Run Control Window|RunControl]]** to assert new trigger condition | ||
| - | |||
| - | * Select **[[s800 SpecTcl|Spectcl]]** window **S800_DISPMATCH.win** | ||
| - | | ||
| - | |||
| - | * We need to start checking the spectra showing the correlations between angle and position in both dispersive and non-dispersive directions. We typically use the spectrum **CRDC1.XG_CRDC1.TAC** for the non-dispersive direction, and **S800.FP.TRACK.XFP_TRACK.AFP** for the dispersive direction | ||
| - | | ||
| - | * The parabolas seen in the above spectra correspond to reactions with H in the target. The blurred lines on the right of the parabolas correspond to reaction with C. It is hard to see clearly this lines, so we need to make several gates | ||
| - | * Open spectrum **E1.DE_TOF.RF** and define a gate around < | ||
| - | | ||
| - | * This gate is used to fill spectra **S800.FP.TRACK.XFP_TRACK.AFP!FOI** and **CRDC1.XG_CRDC1.TAC!FOI**. As can be seen in the figures below, this gate " | ||
| - | | ||
| - | * Define rectangular gates in this spectra, making sure that it is narrow enough to select a vertical section of the parabolas, but wide enough to get enough statistics. Call them **afp** (in spectrum **CRDC1.XG_CRDC1.TAC!FOI**) and **bfp** (in spectrum **S800.FP.TRACK.XFP_TRACK.AFP!FOI**). After applying these new gates, the kinematics spectra are very clean | ||
| - | {{: | ||
| - | * The pre-defined gate **allgates** is made by the AND condition of all the gates defined above (**foi**, **afp**, and **bfp**). This gate is used to fill the spectrum **CRDC1.XG!FOI-AFP-BFP**, | ||
| - | | ||
| - | * 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 on the left side of u6pc5 are **I232TA**, **I236TC**, and **I245TC** which can be found on page **S800 BLine+Spectrograph**. Other elements used to improve the focusing in the object point, and the transmission are **I172QA** and **I174QB**. The goal of the dispersion-matching tuning is to find a compromise between transmission and resolution. | ||
| - | | ||
| - | * 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 | ||
| - | {{: | ||
tuning_the_s800_xdt.txt · Last modified: 2023/09/22 15:15 by swartzj
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