Difference between revisions of "CDC recent run drift times"
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|[[Image:cdc_run2839_ampt.png|thumb|x200px|max amplitude vs time]] | |[[Image:cdc_run2839_ampt.png|thumb|x200px|max amplitude vs time]] | ||
|[[Image:cdc_run2839_ampst.png|thumb|x200px|max amplitude - pedestal, straw 1021]] | |[[Image:cdc_run2839_ampst.png|thumb|x200px|max amplitude - pedestal, straw 1021]] | ||
− | |[[Image:cdc_run2839_amp.png|thumb|x200px|max amplitude - pedestal | + | |[[Image:cdc_run2839_amp.png|thumb|x200px|max amplitude - pedestal]] |
|} | |} | ||
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|[[Image:cdc_run2839_thr40_t30z.png|thumb|x200px|zoomed in (threshold too low)]] | |[[Image:cdc_run2839_thr40_t30z.png|thumb|x200px|zoomed in (threshold too low)]] | ||
|[[Image:cdc_run2839_thr40_ped.png|thumb|x200px|pedestal]] | |[[Image:cdc_run2839_thr40_ped.png|thumb|x200px|pedestal]] | ||
− | |[[Image:cdc_run2839_thr40_amp.png|thumb|x200px|max amplitude - pedestal | + | |[[Image:cdc_run2839_thr40_amp.png|thumb|x200px|max amplitude - pedestal]] |
|} | |} | ||
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|[[Image:cdc_run2839_thr60_t30z.png|thumb|x200px|zoomed in]] | |[[Image:cdc_run2839_thr60_t30z.png|thumb|x200px|zoomed in]] | ||
|[[Image:cdc_run2839_thr60_ped.png|thumb|x200px|pedestal]] | |[[Image:cdc_run2839_thr60_ped.png|thumb|x200px|pedestal]] | ||
− | |[[Image:cdc_run2839_thr60_amp.png|thumb|x200px|max amplitude - pedestal | + | |[[Image:cdc_run2839_thr60_amp.png|thumb|x200px|max amplitude - pedestal]] |
|} | |} | ||
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|[[Image:cdc_run2839_thr65_t30z.png|thumb|x200px|zoomed in]] | |[[Image:cdc_run2839_thr65_t30z.png|thumb|x200px|zoomed in]] | ||
|[[Image:cdc_run2839_thr65_ped.png|thumb|x200px|pedestal]] | |[[Image:cdc_run2839_thr65_ped.png|thumb|x200px|pedestal]] | ||
− | |[[Image:cdc_run2839_thr65_amp.png|thumb|x200px|max amplitude - pedestal | + | |[[Image:cdc_run2839_thr65_amp.png|thumb|x200px|max amplitude - pedestal]] |
+ | |} | ||
+ | |||
+ | {| border="0" cellpadding="2" | ||
+ | |+ Same thresholds as previous, plots for all straws, not just neatest time group, hit threshold: 65-53-13, window 45-145 | ||
+ | |- | ||
+ | |[[Image:cdc_run2839_thr65_pn.png|thumb|x200px|pedestal vs straw #]] | ||
+ | |[[Image:cdc_run2839_thr65_tn.png|thumb|x200px|time vs straw #]] | ||
+ | |[[Image:cdc_run2839_thr65_an.png|thumb|x200px|max amplitude - pedestal vs straw #]] | ||
+ | |- | ||
+ | |[[Image:cdc_run2839_thr65_tnz.png|thumb|x200px|time vs straw #]] | ||
+ | |[[Image:cdc_run2839_thr65_anz.png|thumb|x200px|max amplitude - pedestal vs straw #]] | ||
+ | |[[Image:cdc_run2839_thr65_a255.png|thumb|x200px|max amplitude straw 255]] | ||
|} | |} |
Revision as of 15:05, 20 April 2015
Fitted drift time function to straws in run 2451, picked straws with tmax slope < 30, used same straws for subsequent runs.
Used same hit thresholds & window for all runs.
The drift times are for a small group of straws. In the earlier runs the amplitude histograms are cut off at the lower end by the sparsification threshold. There are a few straws with noise (and threshold) low enough that the MPV is visible. The max amplitude histograms show entries below the sparsification threshold because I used a lower threshold for analysis, added to the pedestal just before the peak; often there is a smaller peak before a larger one; less often the pedestal rises between the start of the data window and the peak.
Contents
- 1 Summary up to run 2713
- 2 Run 2451 - solenoid off
- 3 Run 2551 - solenoid off
- 4 Run 2560 - solenoid off
- 5 Run 2577 - solenoid off
- 6 Run 2616 - solenoid at 1200A
- 7 Run 2617 - solenoid at 1200A
- 8 Run 2619 - solenoid at 1200A
- 9 Runs 2616 to 2619 combined - solenoid at 1200A
- 10 Run 2642 - solenoid off
- 11 Run 2644 - solenoid off
- 12 Run 2649 - solenoid off
- 13 Run 2676 - solenoid off
- 14 Run 2688
- 15 Run 2692 - solenoid off
- 16 Run 2713 - solenoid off
- 17 Run 2839 - solenoid off
Summary up to run 2713
Removing alcohol decreased max drift time by 20ns and decreases gain by at least 20%.
Decreasing CO2 gas conversion factor from 0.773 to 0.74 increased max drift time by 8s and decreased gain slightly (difficult to quantify the gain decrease).
Moving the CO2 from controller CH2 to 4 and switching the mixer from rate to blend and back caused only very small changes, if any.
Changing the CO2 gas conversion factor from 0.74 to 1.0 decreased max drift time by 70ns and increased gain x 236%
Run 2451 - solenoid off
7 Feb 2015. First run of 2015. Increased sparsification thresholds from 7sigma to 15sigma.
Garfield 0T 55.78% Ar 43.82% CO2 0.4% 2-propanol (0.4% propanol added to mix of 56% Ar + 44% CO2) has t 561ns @ 0.76cm, tmax 577ns @ 0.77cm
Adding 0.5% 2-propanol to 56/44 Ar/CO2 gives Garfield t of 565ns @ 0.76cm and 1% 2-propanol gives Garfield t of 590ns @ 0.76cm
With a gas mix of 65/44, time < (550-t0) x 0.8ns = 66ns corresponds approximately to drift radius < 2.9mm
Run 2551 - solenoid off
2-3 March 2015. 3 weeks after disengaging the alcohol bubbler.
Compared with run 2451, drift velocity has increased and gain decreased (but cannot measure the gain decrease very well due to thresholds).
Garfield 0T 56% Ar 44% CO2 has t ~543ns @ 0.76cm, 558ns @ 0.77cm
Garfield 0T 57% Ar 43% CO2 has tmax ~543ns @ 0.77cm
|} |
Run 2560 - solenoid off
8 March 2015. 5 days after changing the CO2 gas factor from 0.773 to 0.74 (should result in increase in CO2 %). The gas factor was changed before run 2552.
Comparing with run 2551, drift velocity and gain have both decreased slightly (consistent with more CO2).
Run 2577 - solenoid off
10 March 2015. 1 day after changing the gas mixer MFCs from master/slave "blend" to independent "rate" mode (this change was made before run 2563). For this run the readout window is different from that in all the others.
Run 2616 - solenoid at 1200A
11 March 2015. 2 days after changing the gas mixer MFCs from master/slave "blend" to independent "rate" mode.
Drift times increased substantially due to the magnetic field. Amplitude not inconsistent with that from run 2560 (lower stats in this run).
Garfield 1.75T 56% Ar 44% CO2 has t ~597ns @ 0.76cm, 613ns @ 0.77cm
Garfield 1.75T 57% Ar 43% CO2 has tmax 603ns @ 0.77cm
Garfield 1.75T 57.5% Ar 42.5% CO2 has tmax 596ns @ 0.77cm
Run 2617 - solenoid at 1200A
11 March
Run 2619 - solenoid at 1200A
12 March
Runs 2616 to 2619 combined - solenoid at 1200A
11-12 March
Run 2642 - solenoid off
14 March. After moving CO2 controller from ch2 to ch4 (on March 13) and decreasing sparsification thresholds to 8sigma
Run 2644 - solenoid off
16 March.
Run 2649 - solenoid off
17 March. 10 hours after returning CO2 controller from ch4 to ch2
Run 2676 - solenoid off
22 March.
Run 2688
26 March. switched gas mixer back from independent "rate" mode into "blend" mode
Run 2692 - solenoid off
27 March. 1 day after switching gas mixer back from independent "rate" mode into "blend" mode
Run 2713 - solenoid off
6 April. 1 day after changing the CO2 gas conversion factor from 0.74 to 1.0
Comparing tmax with Garfield, this looks like 61.5% Ar 38.5% CO2
Run 2839 - solenoid off
17 April. **With HV filters** ~ 7 days after changing the CO2 gas conversion factor to 0.5
Tightening the window to 45-145 did not change the max drift time estimate.