Difference between revisions of "Minutes-1-7-2016"

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# Electronics (Fernando, Chris, Nick)
 
# Electronics (Fernando, Chris, Nick)
 
# Other   
 
# Other   
 
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= Minutes =
 
= Minutes =
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== F125 Update ==
 
== F125 Update ==
  
- Naomi reported on the f125 firmware status (see link above).   
+
- Naomi reported on the test of the f125 firmware status (see link above). She compared the emulated results using the raw data with the firmware quantities. After fixing with Cody several problems, only a few and very rare issues remain as listed in the link. The issue with the short events initially caused crashing of the analyzing software but was eventually fixed by David L.   
  
== CDC update ==
+
- Eugene: analyzer shouldn't crash, has to have some checks of the buffer sizes. Fernando: important is to understand if the errors are random (most likely timing issues in the firmware), or related mostly to a certain hardware (hardware issues).
 
+
- Mike showed plots with time-to-distance deformation corrections now WITH magnetic field. They look close to the Garfield predictions. Next step is to apply the corrections and look at the beam data also for different runs.
+
 
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- Cody fixed several bugs in the firmware and updated the fADCs in the CDC crates only. The issues were found by Naomi: end of window algorithm fails if no peak was found, issues with the overflow bit when summing; and other. The plan is to have a cosmic run today/tonight with CDC to check the fixes. Cody also swapped two CDC modules. Cody is out starting this Monday.
+
  
 
== FDC update ==
 
== FDC update ==
  
- Luke looked at the cosmic data with the FDC and updated the spreadsheet (linked above) with the problematic channels: green - channels that were not working before and now are OK, red - new bad channels, all the rest no change in the status. The green is more than the red meaning we have lower percentage of bad channels, which is of the order of 0.5%.
+
- During the last run there was an attempt to set HV on the FDC without magnetic field. As explained in the entry above by Luke: many HV channels tripped when they switched to 10^-4 radiator at 50nA current at 2050V (compared to 2200V nominal) with 1uA trip limit. Interestingly half of the channels were not central, i.e. with HV sectors just next to the beam, but >20cm on the side.  
 
+
- Looking at the results with 55Fe source on the spare package Lubomir found that the gain at the wire closest to the source is factor of 2 lower than the gain on the side wires (first plot with 1700V/-0V, second with 1600V/-400V Ar/CO2 90/10). The averaged charge for each wire is normalized by moving the source away from the front window. The gain drops due to the high rates. Using a scope and lowering the threshold till the rate stopped depending on it, we measured with Luke rates of ~40kHz. In case of MIP in the standard cells we expect the same gain drop by a factor of two to happen at ~100kHz (ratio of primary electrons for (6keV photons)/(1cm MIP) is 230/90).  
+
 
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- The TRD test is ready to go (just need beam) - follow the link above. Sergey and Lubomir installed radiators with different thicknesses in front of the spare package (see picture above).
+
 
+
== Electronics ==
+
 
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- Nick is going to look at the last CDC LV module. It had 4 channels (out of 8) connected and was OK, but then we connected 3 extra channels for the spare FDC package and showed some issues. The plan is to replace the module.  
+
  
== Other ==
+
- Results from the TRD test in the last run are very promising. The first two attached plots show the amplitude (proportional to dE/dx) vs drift time and horizontal coordinate for two radiator configurations. One can clearly sees the places with radiator: higher amplitudes especially for big drift time. This is also shown when comparing the amplitudes vs drift time
 +
with and without radiator (next two plots). The difference between the two (last plot) comes from the transition radiation photons and as a function of the drift time (roughly proportional to photon interaction point along the electron track) is consistent with Sergey's simulations.
  
- Lubomir will be out of the country next two weeks, accessible via e-mails. Next DC meeting will be in January, unless there is an additional announcement.
+
== NIM papers ==
  
-->
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- This was a reminder that it is now time to start writing NIM papers on the two detectors. The tex templates were prepared by Beni some time ago (see [https://halldweb1.jlab.org/wiki/index.php/Minutes-11-19-2015 11/19/2015 meeting minutes]).

Latest revision as of 18:23, 8 January 2016

January 7, 2016 Drift Chamber meeting

Connection

  1. Instructions for Bluejeans meeting connection
  2. Meeting ID: 290664653
  3. To join via a Web Browser, go to the page [1] https://bluejeans.com/290664653.

Agenda

  1. NIM Papers
  2. Spring 2016 Run Planning Meeting
  3. CDC update (Beni/Mike)
  4. FDC update (Lubomir)
  5. F125 Update (Naomi)
  6. Electronics (Fernando, Chris, Nick)
  7. Other

Minutes

Participants: Curtis, Naomi, Mike (CMU), Sean (NU), Fernando, Eugene, Luke, Chris, Nick, Simon, Beni, and Lubomir (JLab).

Spring 2016 Run Planning Meeting

- In preparation for the coming run need to perform complete tests of the detectors: should start taking cosmic data early next week. Expect to have physics data taking at least at the end of the run (once the calorimeters are calibrated).

- FDC was turned on few days ago. One positive HV channel (second package, most downstream cell, side HV sector) draws huge current, can be operated at 200V below nominal. The problem started in early December. Most likely it's outside of the gas volume since the filed HV is not affected. It has been checked that it is not the HV module. Fixing will require access to the HV connection (at the bottom of the second package) and it can't be done now. If needed (still 1% of the sensitive area) can be done during the summer. CDC has not been turned on yet.

F125 Update

- Naomi reported on the test of the f125 firmware status (see link above). She compared the emulated results using the raw data with the firmware quantities. After fixing with Cody several problems, only a few and very rare issues remain as listed in the link. The issue with the short events initially caused crashing of the analyzing software but was eventually fixed by David L.

- Eugene: analyzer shouldn't crash, has to have some checks of the buffer sizes. Fernando: important is to understand if the errors are random (most likely timing issues in the firmware), or related mostly to a certain hardware (hardware issues).

FDC update

- During the last run there was an attempt to set HV on the FDC without magnetic field. As explained in the entry above by Luke: many HV channels tripped when they switched to 10^-4 radiator at 50nA current at 2050V (compared to 2200V nominal) with 1uA trip limit. Interestingly half of the channels were not central, i.e. with HV sectors just next to the beam, but >20cm on the side.

- Results from the TRD test in the last run are very promising. The first two attached plots show the amplitude (proportional to dE/dx) vs drift time and horizontal coordinate for two radiator configurations. One can clearly sees the places with radiator: higher amplitudes especially for big drift time. This is also shown when comparing the amplitudes vs drift time with and without radiator (next two plots). The difference between the two (last plot) comes from the transition radiation photons and as a function of the drift time (roughly proportional to photon interaction point along the electron track) is consistent with Sergey's simulations.

NIM papers

- This was a reminder that it is now time to start writing NIM papers on the two detectors. The tex templates were prepared by Beni some time ago (see 11/19/2015 meeting minutes).