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tuning_the_s800_xdt [2019/03/13 21:20] pereira |
tuning_the_s800_xdt [2023/08/18 17:49] pereira [Object scintillator setup] |
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* Ensure that the S800 spectrograph magnets are tuned to the right rigidity | * Ensure that the S800 spectrograph magnets are tuned to the right rigidity | ||
- | * Verify that the beam blocker | + | * Verify that the FP beam blocker is fully open: |
- | * Expected " | + | |
- | + | ||
- | * 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** | ||
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* For U-238 (88+) @ ~70 MeV/u: UP (1180 V); DOWN (1280 V) | * For U-238 (88+) @ ~70 MeV/u: UP (1180 V); DOWN (1280 V) | ||
- | * Have a good expectation of rate from A1900 group information or from timing scintillators (typically | + | * Have a good expectation of rate from ARIS group information or from timing scintillators (typically |
- | * Remove stops to look for beam at S800 FP with **[[s800 daq tools# | + | * Remove stops to look for beam at S800 FP with **[[s800 daq tools# |
* Look at FP scintillator scalers (E1 up, E1 down) | * Look at FP scintillator scalers (E1 up, E1 down) | ||
* There are typically a few scaler counts without beam | * There are typically a few scaler counts without beam | ||
+ | * If needed, adjust beam rate with operators | ||
+ | |||
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* Bias detector. Typical bias: **1200-1800 V** (up to 2200 V) | * Bias detector. Typical bias: **1200-1800 V** (up to 2200 V) | ||
- | * Use **[[electronics overview|scope]]** | + | * Use oscilloscope |
- | * This signal is sent to the CANBERRA 454 Quad CFD in data U6 | + | |
- | * One of the output from this CFD is sent (via patch panel #62) to the TAC and scaler (channel OBJ.Scint) in S3. The other output goes through a passive delayed, and is sent (via patch panel #67) to the Phillips TDC | + | |
* Check raising time and amplitude. Good signal: ~10 ns raising time; 400-500 mV amplitude | * Check raising time and amplitude. Good signal: ~10 ns raising time; 400-500 mV amplitude | ||
+ | * Check if there are reflections (typically seen at ~300 ns after main peak) | ||
* Using the scope, check the CFD setting: | * Using the scope, check the CFD setting: | ||
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* Select SpecTcl window **S800_TOF.win** | * Select SpecTcl window **S800_TOF.win** | ||
- | * The three columns correspond to the **RF-FP** ToF (left), **OBJ-FP** (center), and **XFP-FP** (right) | + | * 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 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 first hit typically provides the " | * The second row corresponds to the MTDC with all the hits included. Note that in a unreacted-beam setting, the first hit typically provides the " | ||
- | * The third row corresponds to the MTDC with only the first hit | + | * 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 fourth row corresponds to the ORTEC TACs. Note that there is not **RF-FP TAC**. |
- | * The two spectra in the fifth row corresponds | + | * The two spectra in the fifth row correspond |
* An empty ToF spectrum means that either the delays are not right (and need to be adjusted) or the spectrum range is too narrow | * 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) | * The MTDC delays should never need to be adjusted because the matching window is sufficiently wide (around 4000 ns) | ||
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* Measure the beam intensity again and calculate the average value | * 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 **/ | * 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 **/ | + | * 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 | * Calculate the rate and purity and compare with the value in the A1900 FP to determine the transmission | ||