Difference between revisions of "Minutes-8-28-2014"

From GlueXWiki
Jump to: navigation, search
(Created page with "August 28, 2014 FDC+CDC meeting = Agenda = # DAQ (Beni) # CDC status (Mike, Beni) # FDC status (Vlad, Lubomir) # Electronics (Chris, Nick) # Engineering (Bill) #* Chiller #* ...")
 
m (Text replacement - "hdops.jlab.org/wiki" to "halldweb.jlab.org/hdops/wiki")
 
(14 intermediate revisions by 2 users not shown)
Line 7: Line 7:
 
# Electronics (Chris, Nick)
 
# Electronics (Chris, Nick)
 
# Engineering (Bill)
 
# Engineering (Bill)
−
#* Chiller
+
#* Chiller [http://www.jlab.org/Hall-D/detector/fdc/drawings/REV_TO_HEAT_EXCHANGER.PNG]
−
#* Cathode scan (Luke)
+
#* Cathode scan [http://www.jlab.org/Hall-D/detector/fdc/calibration/pitch_all.pdf], [http://www.jlab.org/Hall-D/detector/fdc/calibration/delta_mpitch_epitch.pdf] [http://www.jlab.org/Hall-D/detector/fdc/calibration/Pitch_Pos1_RemeasureCompare.pdf] (Luke)
−
# Commissioning [https://hdops.jlab.org/wiki/index.php/Hall_D_Commissioning Wiki Page] (all)
+
# Commissioning [https://halldweb.jlab.org/hdops/wiki/index.php/Hall_D_Commissioning Wiki Page] (all)
 
# Other
 
# Other
  
−
[https://halldweb1.jlab.org/wiki/index.php/Connect_to_Bluejeans_Meetings Instructions for Bluejeans meeting connection]
+
[https://halldweb.jlab.org/wiki/index.php/Connect_to_Bluejeans_Meetings Instructions for Bluejeans meeting connection]
  
 
FDC meeting ID: 290664653
 
FDC meeting ID: 290664653
−
 
−
<!--
 
  
 
= Minutes =
 
= Minutes =
  
−
Participants: Curtis, Naomi (CMU), Sean (NU), Beni, Mike, Luke, Eugene, Chris, Nick, Dave, Bill, Fernando, Sergey, Vlad and Lubomir (JLab).
+
Participants: Curtis, Naomi (CMU), Sean (NU), Beni, Luke, Chris, Nick, Simon, Fernando, and Lubomir (JLab).
  
 
== DAQ ==
 
== DAQ ==
  
−
- Beni: testing the latest fADC125 firmware released, works except something goes wrong in the FPGA when setting event number. ROCFDC3 has problems will be excluded for the next run. We want to take data with the magnet on. The top scintillator paddle was moved as high as possible to reduce the filed on the PMTs. Actually, after the meeting Beni and Elton were able to get signals from the scintillator (after increasing the HV) and started the DAQ (FDC+CDC) with the coincidence trigger.
+
- Beni: testing the latest fADC125 firmware in ROCFDC2. This version has some fixes that Cody did, based on the problems Beni found last week. These tests need DAQ with software trigger. ROCFDC3 has problems: works at the beginning but later has no valid data.
  
−
- Discussions about horizontal trigger. We need to install it back. The upstream paddles can be installed when the target is out. Instead of the downstream paddles one can use the TOF, but it requires the GTP.  
+
- Lubomir: according to Sasha he made a big progress with the GTP using BCAL north side. There are some minor issues but expect soon to have the BCAL up/down coincidence trigger. When it's ready we have to move the CDC/FDC trigger electronics from the bottom to the top trigger crate. The fan on the bottom trigger crate was replaced and there are no more spare fans; not clear what the problem is with these fan units.
  
 
== CDC update ==
 
== CDC update ==
  
−
- Mike showed curved tracks (linked) in the CDC at 600A magnetic field. Some local curvatures seen can be explained if the drift time is taken into account.
+
- Fernado: working with Nick on the CDC noise from the CAEN supply. Contacted CAEN people: they are trying to be helpful. Grounding of the aluminum ring didn't help. They found two HVBs next to each other, one (C5) is very clean while the other (C6) has huge noise varying from channel to channel. Will use them to troubleshoot the noise. The swapping of HV connectors, or moving HV wires didn't change anything. Tomorrow will continue with "swapping everything" to find the problem.
−
 
+
−
- Fernado: additional ground on the CDC aluminum ring to which the HV is connected has been installed. Expect to reduce the noise significantly. Grounding the HVBs directly will be done as a last resort and it will be done in a different way through the grounding lugs.
+
  
 
== FDC update ==
 
== FDC update ==
  
−
- Lubomir: by applying timing cuts on the hits from the two cathodes and the wires in a cell, one can reduce the threshold down to 50 fADC units (~4mV). As a result we see now most of the "missing" cathode channels, that have problems with the conductive tape. Of course the resolution will be deteriorated but one can still use this information for the pattern recognition. Couple of interesting events are linked above.
+
- Lubomir: FDC not operational right now (see chiller problems below). Vlad is comparing the results of the runs before/during/after the magnet test, will report on the next meeting. One TDC channel stopped working. With a scope we see all the channels. Fernando: swap the two signal cables and if the problem is in the same channel contact Ed.
  
 
== Engineering ==
 
== Engineering ==
  
−
- Bill: problems with the chiller on Monday, it was not regulating the temperature. Tom adjusted the thermostatic valve and it started regulating again. Bill discussed with the company the chiller problems. They say the thermostatic valve must be OK, but the new compressor installed is not quite the same as the original one. They don't have spare units and they don't make visits to fix the chiller. If the problems continue, either we have to swap the compressor, or send the chiller to Indiana for repair, or get a new one from Japan.  The plan for now is to install the heat exchanger (maybe tomorrow) and continue monitoring.
+
- The heat exchanger was installed on Monday but could not regulate the temperature. According the Bill the problem now is that the input water is too warm. There's a bypass valve and when it's completely open and the LV is OFF it regulates the temperature, but that's not the case when th LV is on. Bill ordered parts for a modification (picture shown) that will fix the problem and probably will be installed tomorrow.   
−
 
+
−
- On Monday when the chiller failed, Wesley Moore was working on the epics communication with the device. According to Hovanes he changed the set temperature to a lower value for as short time, then the chiller failed. The plan is just to read the epics variables, and not to write anything to the device. 
+
−
 
+
−
- Luke: we installed the encoder and started measurements at the last position, but in the middle the encoder stopped working. In addition motor got disconnected from the stage. After the meeting the motor was fixed but there were still problems with the encoder. Luke will continue with measurements at two positions. The data with the encoder is enough to compare the two measurement methods.
+
−
 
+
−
== Commissioning ==
+
−
 
+
−
- Curtis presented a plan for the CDC commissioning linked above. When aligning the photon beam several inner HVBs will be supplied by Bertan modules so that one can see the currents which may help in the beam alignment. Then the plan is to have some initial data with magnet on for a short time, then for a longer time with the magnet off, and then with the magnet on again. They are concerned that the timing algorithm on the fADC125 may not be ready for the run. Eugene: while working on the photon beam the magnet will stay at 300A which is safe; this time can be used for the initial data collection.   
+
−
 
+
−
- As Bill proposed on the last meeting it will be good to survey the FDC without magnetic field (planned already for September) and then to monitor one of the reflector while the magnet goes up. Eugene: the best would be to rump up the magnet when the Hall is opened in September and at the same time the survey can be done.
+
−
 
+
−
== Other ==
+
  
−
- Beni: Scot put alcohol in the bubblers, we will monitor the chamber behavior.
+
- Even if the chiller doesn't regulate the temperature it gives OK status and the interlock is not engaged, i.e. one can turn the LV and it will overheat. To avoid this, as a first fix, we want to implement in addition an EPICS interlock (discussed already with Hovanes). Later we will need a temperature sensor with a PLS system to interlock the LV.  
  
−
-->
+
- Luke finished the cathode scan, latest results shown on the first plot: mean pitch over the area of the cathode. One certainly sees the dips in the seam positions and a little bigger pitch in the middle foil, still there are some irregularities. The latest three measurements were done with the cathode rotated 180deg. One of these was done also with the encoder: the difference between the motor and encoder values has ~1 micron sigma (second plot). Finally, one of the measurement was a repetition of the very first measurement: they are consistent (third plot) within 2-4 microns (the error of finding the edge of the strip with the microscope) but in addition there's some systematic error, a slope as function of the strip number, that we can't explain for now. Luke did a great job with the cathode scan, he's leaving tomorrow.

Latest revision as of 07:07, 1 April 2015

August 28, 2014 FDC+CDC meeting

Agenda

  1. DAQ (Beni)
  2. CDC status (Mike, Beni)
  3. FDC status (Vlad, Lubomir)
  4. Electronics (Chris, Nick)
  5. Engineering (Bill)
  6. Commissioning Wiki Page (all)
  7. Other

Instructions for Bluejeans meeting connection

FDC meeting ID: 290664653

Minutes

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

DAQ

- Beni: testing the latest fADC125 firmware in ROCFDC2. This version has some fixes that Cody did, based on the problems Beni found last week. These tests need DAQ with software trigger. ROCFDC3 has problems: works at the beginning but later has no valid data.

- Lubomir: according to Sasha he made a big progress with the GTP using BCAL north side. There are some minor issues but expect soon to have the BCAL up/down coincidence trigger. When it's ready we have to move the CDC/FDC trigger electronics from the bottom to the top trigger crate. The fan on the bottom trigger crate was replaced and there are no more spare fans; not clear what the problem is with these fan units.

CDC update

- Fernado: working with Nick on the CDC noise from the CAEN supply. Contacted CAEN people: they are trying to be helpful. Grounding of the aluminum ring didn't help. They found two HVBs next to each other, one (C5) is very clean while the other (C6) has huge noise varying from channel to channel. Will use them to troubleshoot the noise. The swapping of HV connectors, or moving HV wires didn't change anything. Tomorrow will continue with "swapping everything" to find the problem.

FDC update

- Lubomir: FDC not operational right now (see chiller problems below). Vlad is comparing the results of the runs before/during/after the magnet test, will report on the next meeting. One TDC channel stopped working. With a scope we see all the channels. Fernando: swap the two signal cables and if the problem is in the same channel contact Ed.

Engineering

- The heat exchanger was installed on Monday but could not regulate the temperature. According the Bill the problem now is that the input water is too warm. There's a bypass valve and when it's completely open and the LV is OFF it regulates the temperature, but that's not the case when th LV is on. Bill ordered parts for a modification (picture shown) that will fix the problem and probably will be installed tomorrow.

- Even if the chiller doesn't regulate the temperature it gives OK status and the interlock is not engaged, i.e. one can turn the LV and it will overheat. To avoid this, as a first fix, we want to implement in addition an EPICS interlock (discussed already with Hovanes). Later we will need a temperature sensor with a PLS system to interlock the LV.

- Luke finished the cathode scan, latest results shown on the first plot: mean pitch over the area of the cathode. One certainly sees the dips in the seam positions and a little bigger pitch in the middle foil, still there are some irregularities. The latest three measurements were done with the cathode rotated 180deg. One of these was done also with the encoder: the difference between the motor and encoder values has ~1 micron sigma (second plot). Finally, one of the measurement was a repetition of the very first measurement: they are consistent (third plot) within 2-4 microns (the error of finding the edge of the strip with the microscope) but in addition there's some systematic error, a slope as function of the strip number, that we can't explain for now. Luke did a great job with the cathode scan, he's leaving tomorrow.

Retrieved from "https://halldweb.jlab.org/wiki/index.php?title=Minutes-8-28-2014&oldid=65866"