tuning_the_s800_xdt
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tuning_the_s800_xdt [2023/08/18 18:01] pereira [CRDCs setup] |
tuning_the_s800_xdt [2025/03/07 14:07] (current) swartzj |
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| This page gives the steps that are followed when tuning the S800. The two possible tuning modes are included, namely, the Focus mode and the Dispersion-matching mode. | This page gives the steps that are followed when tuning the S800. The two possible tuning modes are included, namely, the Focus mode and the Dispersion-matching mode. | ||
| - | Before proceeding, it is mandatory to complete all the steps of the [[to-do list|to-do]] list necessary to prepare the S800 for tuning. The preparation of the S800 for tuning is covered by the A1900 prior to every experiment. | + | Before proceeding, it is mandatory to complete all the steps of the [[to-do list|to-do]] list necessary to prepare the S800 for tuning. The preparation of the S800 for tuning is covered by the S800 group prior to every experiment. |
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| ===== 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 A2400) after passing through the S800 target. This is where the term " |
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| * Use oscilloscope to look at analog signal patched out to data U4 | * Use oscilloscope to look at analog signal patched out to data U4 | ||
| - | * Check raising | + | * Check rise time and amplitude. Good signal: ~10 ns rise time; 400-500 mV amplitude |
| * Check if there are reflections (typically seen at ~300 ns after main peak) | * Check if there are reflections (typically seen at ~300 ns after main peak) | ||
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| * Adjust biases so that unreacted beam are at 1/3 to 1/4 of dynamic range | * Adjust biases so that unreacted beam are at 1/3 to 1/4 of dynamic range | ||
| * Reaction product will typically be similar enough to unreacted beam particles | * Reaction product will typically be similar enough to unreacted beam particles | ||
| - | * Different particles with different energy | + | * Different particles with different energy |
| | | ||
| {{: | {{: | ||
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| * **[[hv bias#hv remote control|Bias]]** CRDCs | * **[[hv bias#hv remote control|Bias]]** CRDCs | ||
| * Look at anode signal on **[[electronics overview|scope]]** | * Look at anode signal on **[[electronics overview|scope]]** | ||
| - | * Patched to data-U6 on labeled connector | + | * Patched to data-U4 on labeled connector |
| * **200 – 500 mV** signals are good | * **200 – 500 mV** signals are good | ||
| * CRDC1 anode is noisier (digital noise) than CRDC2 | * CRDC1 anode is noisier (digital noise) than CRDC2 | ||
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| * Count rate is a little higher than on scintillator due to noise or thresholds | * Count rate is a little higher than on scintillator due to noise or thresholds | ||
| - | * Check **[[s800 SpecTcl|Spectcl]]** window **S800_CRDCS.win** (see figure below), or, alternatively **S800_MEGASUMMARY.win** to verify the good performance of the detectors. (The spectra for each CRDC can be checked | + | * Check **[[s800 SpecTcl|Spectcl]]** window **S800_CRDCS.win** (see figure below), or, alternatively **S800_MEGASUMMARY.win** to verify the good performance of the detectors. (The spectra for each CRDC can be checked |
| * Spectra **crdc1.raws** and **crdc2.raws** | * Spectra **crdc1.raws** and **crdc2.raws** | ||
| - | * Each spectra | + | * Each spectrum |
| * The 224 pads are assembled along the dispersive direction | * The 224 pads are assembled along the dispersive direction | ||
| * Width of beam peak is proportional to A1900 p-acceptance in focus optics | * Width of beam peak is proportional to A1900 p-acceptance in focus optics | ||
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| * Make a summing region around the " | * Make a summing region around the " | ||
| * Stop the run and rescan data from disk | * Stop the run and rescan data from disk | ||
| - | * Compare the number of event inside the 2D summing regions with the number of events inside the **ic** gate. Typically the former are very close to the later (nearly 100% efficiency for medium/high Z) | + | * Compare the number of event inside the 2D summing regions with the number of events inside the **ic** gate. Typically the former are very close to the latter |
| {{: | {{: | ||
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| ====== Dispersion Matching Mode ====== | ====== Dispersion Matching Mode ====== | ||
| - | 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, |
| - | Charge-exchange experiments require typically this optics. In some cases, the beam used is < | + | Charge-exchange experiments require typically this optics. In some cases, the beam used is < |
| * Set trigger to “s800 trigger” | * Set trigger to “s800 trigger” | ||
tuning_the_s800_xdt.1692396060.txt.gz · Last modified: 2023/08/18 18:01 by pereira
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