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| − | Participants: Naomi (CMU) Sean(FSU), Eugene, Beni, Simon, Alex A., Thomas, Sergey, and Lubomir (JLab). | + | Participants: Sean(FSU), Eugene, Beni, Simon, Alex A., Alex B., Sergey, and Lubomir (JLab). |
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| | = CDC settings for the rest of the run = | | = CDC settings for the rest of the run = |
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| − | - Beni summarized the information related to the CDC thresholds from the hardware threshold scans and his software threshold scan (p.1.1 above). After long discussion, the conclusion was that the hardware threshold gives a little better yields for the rho production. At the same time there's indication for a plateau at ~140 still to be confirm with the hardware scan above 140. However, the main massage is that the effect is not so big compared to the effect of the timing (p.1.2). Filtering the noise (p.1.3.) also gives some improvements, but the main gain in the yields come from the timing. | + | - Sergey showed an updated version of his report about the CDC background studies. It includes plots of the hit occupancy as function of the beam current with physics trigger and pulser (random) for inner and outer rings. While the two curves (physics and random) are parallel for the outer rings, at high occupancy as it is in the inner ring, this is not the case. There's no quantitative description yet. The plan is to take more data at higher intensities. |
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| − | - Alex A. showed that the effect of the hardware threshold on the hit efficiency is relatively small and acts mainly on the large drift distances (plot attached). | + | - Naomi suggested looking in the phi-asymmetry of the pedestals, that may be coming from the same polarized synchrotron radiation. |
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| − | - Sergey (see presentation above) analyzed the raw signals and sorted them in several categories: normal, saturated, "photons", cross-talk. He studied their percentage for many raw-mode runs (unfortunately at different condition); for "standard" 2018 running the background events are about 35%. He estimated the shadowing effect to be about 3-5%. Sergey proposed different filtering methods (like Time-Over-Threshold) eventually to be implemented in the firmware. Simom is using Sergey's noise filtering on the raw data to see the effect on the rho production. | + | - |
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| − | - Eugene asked about the amplitude distributions for hits at and out of the tracks. Naomi showed these distributions for different straws. She concluded that some of the straws (only several cards) are noisy and for these higher threshold (~140) would cut the noise, but that is not the case for the majority of the signals.
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| − | - The conclusion is that based on the information that we have, the hardware thresholds are not so critical (in contrast to the timing cut/window that is already implemented). We still want to have a minimal threshold of 110 plus some special thresholds for the noisy channels. Naomi/Beni will generate these thresholds for the rest of the run. This conclusion may not be valid for reactions other than rho production, or for different pattern recognition in the CDC.
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| − | = Other =
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| − | - Sean studied in MC the BCAL vs Start Counter timings for proton tracks in the CDC. BCAL shows some deviations from the generated time at small p_T.
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