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tuning_the_s800_xdt [2015/10/22 16:48] pereira |
tuning_the_s800_xdt [2015/10/26 12:33] pereira [Timing setup] |
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====== Focus Mode ====== | ====== Focus Mode ====== | ||
For most of the experiments in the S800, the analysis line is run in focus mode. In this optics, the analysis line is achromatic, i.e. the dispersive position of the beam focused in the target area (pivot point) does not depend on the momentum. Thus, this mode provides the biggest momentum acceptance (4%). On the other hand, since the spectrograph focal plane is chromatic, the resolution is limited to about 1 part in 1000 in energy. | For most of the experiments in the S800, the analysis line is run in focus mode. In this optics, the analysis line is achromatic, i.e. the dispersive position of the beam focused in the target area (pivot point) does not depend on the momentum. Thus, this mode provides the biggest momentum acceptance (4%). On the other hand, since the spectrograph focal plane is chromatic, the resolution is limited to about 1 part in 1000 in energy. | ||
+ | |||
===== Unreacted beam ===== | ===== Unreacted beam ===== | ||
In the first part of the XDT, the rigidity of the S800 is typically set to match the value of the fragment beam (selected in the A1900) after passing through the S800 target. This is where the term " | In the first part of the XDT, the rigidity of the S800 is typically set to match the value of the fragment beam (selected in the A1900) after passing through the S800 target. This is where the term " | ||
- | === 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 |
+ | * Make sure that the time range of spectra is wide enough (e.g. between -3000 to 3000) | ||
+ | * 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 | ||
+ | * 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 of OBJ-FP and XFP-FP ToFs (zoomed in). The spectra show the ToF (vertical axis) vs. hit number (horizontal axis). In an unreacted setting, one expects to see the most of the " | ||
+ | |||
+ | {{: | ||
* Although the ToF reference (" | * Although the ToF reference (" | ||
- | * 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) | + | * 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) |
* MTDC: | * MTDC: | ||
* Before getting into the MTDC, the OBJ, XFP, and E1 up signals in the MTDC go through a Mesytec MCFD | * Before getting into the MTDC, the OBJ, XFP, and E1 up signals in the MTDC go through a Mesytec MCFD | ||
* 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 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 XFP signal into the MCFD module comes from data-U6 patch panel #70, connected to the CANBERRA 454 CFD XFP output | * The XFP signal into the MCFD module comes from data-U6 patch panel #70, connected to the CANBERRA 454 CFD XFP output | ||
- | * SpecTcl calculates the ToF by substracting the MTDC time from XFP (MTDC channel | + | * SpecTcl calculates the OBJ-to-Focal-Plane and XFP-to-Focal-Plane ToFs by substracting the E1 up time (MTDC channel |
* The MTDC timing signals do not require external delay adjustments because the matching window is sufficiently wide | * The MTDC timing signals do not require external delay adjustments because the matching window is sufficiently wide | ||
* Tennelec TACs: | * Tennelec TACs: | ||
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* 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 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 | * 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 calculates the OBJ-to-Focal-Plane and XFP-to-Focal-Plane ToFs by substracting the E1 up time (channel 8) to the OBJ time (channel 14) and the XFP time (channel 15) | ||
+ | |||
* 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. | * 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. | ||
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* All of the trigger signals are not pipelined and are thus subject to deadtime | * All of the trigger signals are not pipelined and are thus subject to deadtime | ||
- | === Checking Particle ID and rate at S800 FP === | + | ==== Checking Particle ID and rate at S800 FP ==== |
* Establish PID | * Establish PID | ||
* Refer to information on setting from A1900 FP | * Refer to information on setting from A1900 FP | ||
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- | === 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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- | === Setup beamline === | + | ==== Setup beamline |
* Object and XF scintillators and intermediate image PPACs inserted if they will be used | * 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 | * 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 | ||
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* Set spectrograph Brho for unreacted fragment | * Set spectrograph Brho for unreacted fragment | ||
- | === Start scalers === | + | ==== Start scalers |
* Use s800 account | * Use s800 account | ||
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* scalers (gives error if no bridge) | * scalers (gives error if no bridge) | ||
- | === Setting Optimization === | + | ==== Setting Optimization |
=== Focused optics === | === Focused optics === |