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tuning_the_s800_xdt [2015/10/25 16:27] pereira |
tuning_the_s800_xdt [2015/10/26 14:08] pereira [Reaction Setting] |
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- | === Send beam to FP === | + | ==== Send beam to FP ==== |
* Ensure that the S800 spectrograph magnets are tuned to the right rigidity | * Ensure that the S800 spectrograph magnets are tuned to the right rigidity | ||
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- | === Object scintillator setup === | + | ==== Object scintillator setup ==== |
* Bias detector. Typical bias: **1200-1800 V** (up to 2200 V) | * Bias detector. Typical bias: **1200-1800 V** (up to 2200 V) | ||
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* Watch for no rate change on scaler display with a bias adjustment up or down of about 50-100 V | * Watch for no rate change on scaler display with a bias adjustment up or down of about 50-100 V | ||
- | === FP scintillator setup === | + | ==== FP scintillator setup ==== |
* Set trigger to “s800 trigger” | * Set trigger to “s800 trigger” | ||
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- | === Ionization Chamber setup === | + | ==== Ionization Chamber setup ==== |
* Gas should be [[Gas handling system# | * Gas should be [[Gas handling system# | ||
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- | === CRDCs setup === | + | ==== CRDCs setup ==== |
* **[[hv bias#hv remote control|Bias]]** CRDCs | * **[[hv bias#hv remote control|Bias]]** CRDCs | ||
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- | === Timing setup === | + | ==== Timing setup ==== |
+ | At present, there are three electronic " | ||
- | Overview: | ||
- | * There are three electronic " | + | * Select SpecTcl window **S800_TOF.win** |
- | * Although | + | * The three columns correspond to the **RF-FP** |
- | * 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) | + | * The first (top) row corresponds to the Phillips TDC |
- | * MTDC: | + | * The second row corresponds to the MTDC with all the hits included |
- | * Before getting into the MTDC, the OBJ, XFP, and E1 up signals in the MTDC go through a Mesytec MCFD | + | * The third row corresponds to the MTDC with only the first hit |
- | * 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) | + | * The fourth row corresponds to the ORTEC TACs. Note that there is not **RF-FP TAC** |
- | * The XFP signal into the MCFD module comes from data-U6 patch panel #70, connected | + | * The two spectra in the fifth row corresponds |
- | * SpecTcl calculates the OBJ-to-Focal-Plane | + | * 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 timing signals do not require external delay adjustments | + | * The MTDC spectra should never be empty because the matching window is sufficiently wide (around 4000 ns) |
- | * Tennelec TACs: | + | |
- | * The OBJ **stop** signal to the " | + | |
- | * The XFP **stop** signal to the " | + | |
- | * Phillips TDC: | + | {{:wiki:SpecTcl-e14019-run103.jpg? |
- | * The OBJ 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 #67 | + | |
- | * 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 | + | |
- | * SpecTcl | + | |
- | | + | |
+ | * Using the [[S800 DAQ tools# | ||
+ | * Select the timing | ||
+ | * Adjust the TDC delays of OBJ and XFP using the delay boxes connected to the CANBERRA CFD 454 in data U6 | ||
+ | * Adjust the TDC delays of E1 up, down using the Delay GUI | ||
+ | * In principle, the TACs delays don' | ||
- | * 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 | ||
+ | ==== Checking Particle ID and rate at S800 FP ==== | ||
- | | + | * Select SpecTcl window **S800_PID.win** in directory **/ |
+ | | ||
+ | * The first (top) row corresponds to the Phillips | ||
+ | * The second row corresponds to the MTDC with just the first hit included | ||
+ | * The third row corresponds to the ORTEC TACs. Note that there is not **RF-FP TAC** | ||
+ | * You might need to adjust the limits of the spectra | ||
- | * 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 | ||
+ | * Establish PID and measure rate | ||
+ | * Determine the blob that corresponds to the unreacted beam (refer to information on setting from A1900 FP) | ||
+ | * 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 **/ | ||
+ | * 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 | ||
- | * See [[http:// | ||
- | * 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) ==== |
* " | * " | ||
* Classic PPACs have rate limitations from pileups | * Classic PPACs have rate limitations from pileups | ||
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+ | ==== Setting Optimization ==== | ||
- | === Setup beamline | + | === Focused optics |
- | * 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 === | ||
- | |||
- | === 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 | ||
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- | === 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 | + | ==== Coincidences ==== |
- | * Document optimized transmission with another run to disk to measure rate of fragment of interest at S800 FP | ||
- | |||
- | |||
- | ===== Reaction Setting ===== | ||
- | |||
- | ==== Setting up Reaction Settings ==== | ||
- | * Calculating reaction setting | ||
- | * Center unreacted beam at S800 FP | ||
- | * Adjust spectrograph Brho to center beam at S800 FP | ||
- | * Requirements for a beam to be “Centered” | ||
- | * Spectrograph dipoles matched | ||
- | * Beam position within about 1 cm of center as judges by 0 point on crdc1x spectrum or on track.xfp spectrum | ||
- | * Record run to disk to document centered unreacted beam setting | ||
- | * Calculate reaction setting using “effective” beam energy and the nominal target thickness | ||
- | * Ideally, experimenters should be the ones making this calculation | ||
- | * This approach assumes that the target thickness is known | ||
- | |||
- | |||
- | * Reaction setting to FP | ||
- | * Start with Attenuator setting of unreacted beam and step up in intensity | ||
- | * Set up beam blocker, if necessary | ||
- | * 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 | ||
- | * A graphic tool is available to help (not yet calibrated) | ||
- | * Try to cut only as much as necessary; depends on | ||
- | * What rate limits allow | ||
- | * 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 | ||
- | |||
- | ==== 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. | ||
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====== Dispersion Matching tuning ====== | ====== 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, | 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, | ||
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* 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 | ||
{{: | {{: | ||
+ | |||
+ | |||
+ | ====== Reaction Setting ====== | ||
+ | |||
+ | ===== Setting up Reaction Settings ====== | ||
+ | |||
+ | * Calculating reaction setting | ||
+ | * Center unreacted beam at S800 FP | ||
+ | * Adjust spectrograph Brho to center beam at S800 FP | ||
+ | * Requirements for a beam to be “Centered” | ||
+ | * Spectrograph dipoles matched | ||
+ | * Beam position within about 1 cm of center as judges by 0 point on crdc1x spectrum or on track.xfp spectrum | ||
+ | * Record run to disk to document centered unreacted beam setting | ||
+ | * Calculate reaction setting using “effective” beam energy and the nominal target thickness | ||
+ | * Ideally, experimenters should be the ones making this calculation | ||
+ | * This approach assumes that the target thickness is known | ||
+ | |||
+ | |||
+ | * Reaction setting to FP | ||
+ | * Start with Attenuator setting of unreacted beam and step up in intensity | ||
+ | * Set up beam blocker, if necessary | ||
+ | * 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 | ||
+ | * A graphic tool is available to help (not yet calibrated) | ||
+ | * Try to cut only as much as necessary; depends on | ||
+ | * What rate limits allow | ||
+ | * 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 | ||