tuning_the_s800_xdt
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tuning_the_s800_xdt [2017/07/24 10:48] pereira |
tuning_the_s800_xdt [2023/09/22 15:15] (current) swartzj [CRDCs 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 | + | * Check rise time and amplitude. Good signal: ~10 ns rise time; 400-500 mV amplitude |
| - | * 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 if there are reflections (typically seen at ~300 ns after main peak) |
| - | * Check raising | + | |
| - | * Using the scope, check the CFD setting: | + | |
| - | * Check CFD walk inspect signal in scope by triggering scope with CFD output | + | * Check [[s800 daq tools# |
| + | * Trigger oscilloscope with MCFD output (see labels in patch panel), and plug analog signal | ||
| + | * Verify that MCFD delay is ok | ||
| + | * Adjust MCFD gain based on signal amplitude | ||
| + | * Adjust threshold to minimize noise | ||
| + | * Check if MCFD output displays signals triggered by reflections (~300 ns following main peak). If that is the case, increase thresholds or signal width (this is valid only for low-rate experiments) | ||
| + | * Measure OBJ in scalers and compare it with DB5. Does it make sense? | ||
| + | * Stop beam and verify background (it should be minimum) | ||
| + | |||
| + | | ||
| + | * Check CFD walk: inspect signal in scope by triggering scope with CFD output | ||
| * Ensure that CFD delay cable is ok: about 80% of raising time of the input signal | * Ensure that CFD delay cable is ok: about 80% of raising time of the input signal | ||
| - | * Adjust | + | * Trigger oscilloscope with CFD output, and check analog |
| - | * With beam on/off, check amplitude of signals | + | * Adjust threshold |
| - | * Raise thresholds to get rid of noise signals. | + | * Check if CFD output displays |
| - | * NOTE: Be aware that sometimes, after running for a while, the OBJ box is activated. This results in a non-negligible count rate in OBJ scalers with beam off, which comes from HIGH amplitude signals (not noise). DO NOT try to eliminate this " | + | * Measure OBJ in scalers and compare it with DB5. Does it make sense? |
| - | * The ratio of OBJ to XFP scaler rates (channels OBJ.Scint and XFP.Scint) should reflect the transmission of the cocktail beam (between 60% to 90%, depending on quality of tunning) | + | * Stop beam and verify background (it should be minimum) |
| + | |||
| + | |||
| + | | ||
| + | * Be aware that sometimes, after running for a while, the OBJ box is activated. This results in a non-negligible count rate in OBJ scalers with beam off, which comes from HIGH amplitude signals (not noise). DO NOT try to eliminate this " | ||
| + | * The ratio of OBJ to ARIS (DB5) scaler rates (channels OBJ.Scint and XFP.Scint) should reflect the transmission of the cocktail beam (between 60% to 90%, depending on quality of tunning) | ||
| - | * Adjust MCFD threshold: | ||
| - | * Using the [[s800 daq tools# | ||
| - | * The OBJ signal feeding this module is not patched out to data U6 | ||
| - | * The OBJ signal from MCFD module goes to the Mesytec MTDC module and scaler (channel OBJ.MCFD.Scint) | ||
| - | * 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 | ||
| - | * Save new threshold in configuration file **MCFD16.tcl** | ||
| - | |||
| - | * 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 ==== | ||
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| * 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** in directory **/ | + | * Select **[[s800 SpecTcl|Spectcl]]** window **S800_SCINT.win** in directory **/ |
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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 |
| | | ||
| {{: | {{: | ||
| Line 109: | Line 113: | ||
| {{: | {{: | ||
| - | * Gains are controlled in **s800shpini.tcl** file in directory **s800/operations/daq/usb/Configs** (an example of the content of this file can be seen {{: | + | * Gains are controlled in **s800shpini.tcl** file in directory **/user/s800/s800daq/Configurations** (an example of the content of this file can be seen {{: |
| * First shaper is for ion chamber | * First shaper is for ion chamber | ||
| * Typically, only coarse gains are used | * Typically, only coarse gains are used | ||
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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) 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** |
| * 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 | ||
| * Width is narrower in match optics | * Width is narrower in match optics | ||
| * Adjust anode HV to bring fuzzy maximum to around 600-700 channels (saturation of each pad at ~ 1000 ch) | * Adjust anode HV to bring fuzzy maximum to around 600-700 channels (saturation of each pad at ~ 1000 ch) | ||
| - | * These are good spectra to check if the pad thresholds are properly set. Thresholds are too low if you see that all pads are firing at low energies. If that's the case, increase the pad thresholds in files **s800crdcv1.tcl** and **s800crdcv2.tcl**, | + | * These are good spectra to check if the pad thresholds are properly set. Thresholds are too low if you see that all pads are firing at low energies. If that's the case, increase the pad thresholds in files **s800crdcv1.tcl** and **s800crdcv2.tcl**, |
| * Spectra **crdc1.anode_crdc1.tac** and **crdc2.anode_crdc2.tac** | * Spectra **crdc1.anode_crdc1.tac** and **crdc2.anode_crdc2.tac** | ||
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| * Spectra **crdc1.pad_mult** and **crdc2.pad_mult** | * Spectra **crdc1.pad_mult** and **crdc2.pad_mult** | ||
| - | * They show the distribution of pad multiplicies | + | * They show the distribution of pad multiplicities |
| {{: | {{: | ||
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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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| * 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 | ||
tuning_the_s800_xdt.1500907683.txt.gz · Last modified: 2017/07/24 10:48 by pereira
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