Difference between revisions of "Minutes-6-20-2013"

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= Agenda =
 
= Agenda =
−
# Production [http://www.jlab.org/Hall-D/detector/fdc/clucou/IMG_0516.JPG], [http://www.jlab.org/Hall-D/detector/fdc/clucou/IMG_0511.JPG]
+
# Production [http://www.jlab.org/Hall-D/detector/fdc/clucou/IMG_0516.JPG spare package installed], [http://www.jlab.org/Hall-D/detector/fdc/clucou/IMG_0511.JPG and the people around it]
 
#* Spare package tests (Vlad)
 
#* Spare package tests (Vlad)
 
#* Thicker cell results (Lubomir)  [http://www.jlab.org/Hall-D/detector/fdc/clucou/tek.png], [http://www.jlab.org/Hall-D/detector/fdc/clucou/tek1.png], [http://www.jlab.org/Hall-D/detector/fdc/clucou/tek2.png], [http://www.jlab.org/Hall-D/detector/fdc/clucou/tek00010.png], [http://www.jlab.org/Hall-D/detector/fdc/clucou/tek00011.png], [http://www.jlab.org/Hall-D/detector/fdc/clucou/tek00000.png],  [http://www.jlab.org/Hall-D/detector/fdc/clucou/tek00001.png], [http://www.jlab.org/Hall-D/detector/fdc/clucou/tek00002.png], [http://www.jlab.org/Hall-D/detector/fdc/clucou/tek00003.png], [http://www.jlab.org/Hall-D/detector/fdc/clucou/tek00004.png], [http://www.jlab.org/Hall-D/detector/fdc/clucou/tek00005.png]
 
#* Thicker cell results (Lubomir)  [http://www.jlab.org/Hall-D/detector/fdc/clucou/tek.png], [http://www.jlab.org/Hall-D/detector/fdc/clucou/tek1.png], [http://www.jlab.org/Hall-D/detector/fdc/clucou/tek2.png], [http://www.jlab.org/Hall-D/detector/fdc/clucou/tek00010.png], [http://www.jlab.org/Hall-D/detector/fdc/clucou/tek00011.png], [http://www.jlab.org/Hall-D/detector/fdc/clucou/tek00000.png],  [http://www.jlab.org/Hall-D/detector/fdc/clucou/tek00001.png], [http://www.jlab.org/Hall-D/detector/fdc/clucou/tek00002.png], [http://www.jlab.org/Hall-D/detector/fdc/clucou/tek00003.png], [http://www.jlab.org/Hall-D/detector/fdc/clucou/tek00004.png], [http://www.jlab.org/Hall-D/detector/fdc/clucou/tek00005.png]
 
# Engineering (Bill)
 
# Engineering (Bill)
 
# Electronics (Chris, Nick)
 
# Electronics (Chris, Nick)
−
# Full electronics test [https://halldweb1.jlab.org/elog-halld/FDC FDC E-log] (Beni)
+
# Full electronics test [https://halldweb.jlab.org/elog-halld/FDC FDC E-log] (Beni)
 
# Other
 
# Other
−
 
−
<!--
 
  
 
= Minutes =
 
= Minutes =
  
−
Participants: Bill, Dave, Chris, Nick, Simon, Vlad, Beni, Eugene, and Lubomir.
+
Participants: Bill, Beni, Simon, Vlad, and Lubomir. Due to the PAC, magnet test going on at the same time, Wiener people coming on site, the turnout was low for this meeting. The meeting was in A110.
  
 
== Production ==
 
== Production ==
  
−
- The spare package with four cells was opened last week on Thursday down to the top of the cell #5 (second from the bottom) to fix the gas leakage in an O-ring of the spacer ring there (the O-ring was mashed). The place on a wire showing a "point noise" in cell #4 (wire frame #27) was cleaned. Then we put again the four cells together, this time swapping the top two wire frames: #27 put on the top and #28 below it. The gas leakage was fixed.  
+
- End of last week we installed the last cell of the last package (see the photos of the package and the happy people around it, attached above). Vlad tested the new cells and found no problems. The top two cells have 3.5 instead of 0.5cm spacer ring. When using iron source Vlad had to increase the HV by 100V to see approximately the same amplitudes as from the regular cells. Very interestingly the last two cells showed very low dark current ~20-30nA, compared to 200-800nA for the other cells. We are not sure why, just because these were the last two wire frames produced, or there's something else related to the special geometry of the cells.
  
−
- At the beginning of this week Vlad tested cells #5-3. The "point noise" disappeared. Another type of noise was also present at three places on the strips coming from wire frames #27 and #28. We observed it long time ago when tested these wire frames and it comes from positive HV traces on the back of the PCBs at the place where the are laminated to the solid part of the G10 wire frame. The frequency of this noise varies between 100-3000Hz and is visible only on the strips at the place where the traces leading to the strip connector are close to the HV trace. Definitely, it is the wire frame responsible since when we swapped the wire frames the noise showed up on the new cathodes. The only way to fix it is to drill the wire frame from the back, but it is not worth doing it since this is only in three places and the frequency is not that high.
+
- First signals on the scope with definitely visible individual clusters over a very long drift time (up to 15 usec) are attached above. We some minimal grounding we were able to lower the noise to <5mV. At the same time we increased the gas gain to about 2-3 x 10^5 by going up with the HV up to 2450/-500V !
−
   
+
Amazingly the two cells were stable at this HV at least for several hours. Having such gas gain we were able to clearly see (scope pictures above) individual electrons corresponding to ~20-30 mV signal. On average we have two electrons per cluster, and really we see some single peaks, and some double/triple peaks separated due to the diffusion. On some of the plots two neighboring channels are shown (with different colors; we used a second differential probe from Fernando) and you can see the transition from one wire to another when the track crosses the filed region between the two wires.
−
- On Wednesday we installed one new cell and right after the meeting we installed the last cell of the last (spare) package! In these two cells we put the thicker version of the spacer ring to study the feasibility for cluster counting. Now the spare package is being flushed with gas.
+
 
 +
- Plans: on Monday we will take the two gusset rings from the spare package since we will need them for a week to build the package spacers. For that, first we will replace the top gusset with a Lexan sheet, then will take the package out of the mounting table and put it upside down using some strong-back. Then we will replace the bottom gusset. After we are done with the spacers we will re-install the gusset rings in the same way. The spare package will go for testing in 126 after we are done with the third package there. The spacers will be installed between the packages and then we will do the practicing with the mock-up.
  
 
== Engineering ==
 
== Engineering ==
  
−
- The water chiller was connected end of last week but there was a very small leak in two T-connectors outside of the package. On the next day after the meeting Bill replaced the connectors and now there's no leak. 
+
- Bill started working on the fixture for the scintillators needed at the Hall for triggering: it is not a problem at all and will consists of unistruts along the cart attached to the cart frame.  
−
 
+
−
- Spacers between the packages: the G10 sheets to be used to build the spacers have been glued. All the rods (three per spacer) have be made. Building the cylinders requires the use of the gusset rings that are now on the spare package. After the test of the spare package is finished we will take the gusset rings from the package for several days to finish the production of the spacers. Bill: the distance between the packages is defined by the width of the G10 sheets. It has been tested and there are several places that have to be grind. If needed we can use shims.
+
  
 +
- Bill was asked by Bruce Lenzer (suggested by Glen) to include the mock-up cabling in their QA plan, since this will verify that the cable density is correct and that there's enough space to the CDC and BCAL. Bill will write a short report after this exercise.
 +
 
== Full electronics tests ==
 
== Full electronics tests ==
  
−
- HV was set on the third package several days ago and there were no trips since then. Initially when the flow was 50ccpm only one channel had problems setting the HV, but already at 100ccpm it was stable. Now the flow is 200ccpm.  
+
- Beni now has the software to sparsify the data from the fADC in the ROC processors. Now he is taking long runs over the night and some results are shown in the E-log entries 110, 111. There you can see the raw signals (one plot per fADC), the profiles of the strips from all the planes connected (4 cells so far), and the wire positions as reconstructed from the strips. The reconstruction method is simplified so far, that's why you see a lot of noise in between the wire positions.  
−
 
+
−
- This week we started working on the cabling (see first two pictures linked above). All the LV cables were connected. This is the first time we test the length of the LV cables between the four connectors on them on a real package. The only problem was at a place where the manifold is, where Vlad had to insert the cable behind the manifold, but it worked. One crate (12 fADC125, or two cells) was connected with signal cables and another one connected on the next day after the meeting. We need one more VXS crate for the last two cells, and Beni asked Fernando about this. 
+
−
 
+
−
-  The LV, together with the cooling system, is powered already second day and works without problems. We are using Beni's LV control system. When powering the LV, he increases the voltage up to a point (at about 7V) when the current no longer increases, corresponding to ~0.45A per preamp.
+
−
 
+
−
- Beni can read now the raw data from all the fADCs in all the crates (see picture of the monitor showing fADC samples linked above). Next on Beni's list is extracting the time and integral for the fired channels in the ROCs.
+
−
 
+
−
== Other ==
+
  
−
- Beni is working on the control interface with the cooling system.
+
- Two fADC channels are not working properly and there are four strips where the problem is in the FDC. In the previous version of these plots there were ~10 missing strips. Vlad and Lubomir fixed all of them by unplugging/plugging the cards and sometimes releasing a little bit the screws on the clamps. Several of the channels were next to a manifold, but those were fixed.  After that two strips re-appeared as problematic and two new strips showed problems. Beni suggested to spray the connectors with a cleaner to see if this will help.
  
−
- We discussed also the requirements for the control of the gas system. Narciso wrote a document explaining it. Beni: the control system must be mostly "passive" except  when the pressure in the mixing volume is out of the limits. In addition we need also automatic response in case of under/over-pressure in the packages or higher pressure difference between the cells.
+
- Plans: the new VXS crate is in 126 and Chris and Nick will install it soon. Next week when Cody is back Beni will take 12 more fADC125s. Then we will connect the last two cells with signal cables and will be able to take data from all the channels.
  
 
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Latest revision as of 01:50, 1 April 2015

June 20, 2013 FDC meeting

Agenda

  1. Production spare package installed, and the people around it
  2. Engineering (Bill)
  3. Electronics (Chris, Nick)
  4. Full electronics test FDC E-log (Beni)
  5. Other

Minutes

Participants: Bill, Beni, Simon, Vlad, and Lubomir. Due to the PAC, magnet test going on at the same time, Wiener people coming on site, the turnout was low for this meeting. The meeting was in A110.

Production

- End of last week we installed the last cell of the last package (see the photos of the package and the happy people around it, attached above). Vlad tested the new cells and found no problems. The top two cells have 3.5 instead of 0.5cm spacer ring. When using iron source Vlad had to increase the HV by 100V to see approximately the same amplitudes as from the regular cells. Very interestingly the last two cells showed very low dark current ~20-30nA, compared to 200-800nA for the other cells. We are not sure why, just because these were the last two wire frames produced, or there's something else related to the special geometry of the cells.

- First signals on the scope with definitely visible individual clusters over a very long drift time (up to 15 usec) are attached above. We some minimal grounding we were able to lower the noise to <5mV. At the same time we increased the gas gain to about 2-3 x 10^5 by going up with the HV up to 2450/-500V ! Amazingly the two cells were stable at this HV at least for several hours. Having such gas gain we were able to clearly see (scope pictures above) individual electrons corresponding to ~20-30 mV signal. On average we have two electrons per cluster, and really we see some single peaks, and some double/triple peaks separated due to the diffusion. On some of the plots two neighboring channels are shown (with different colors; we used a second differential probe from Fernando) and you can see the transition from one wire to another when the track crosses the filed region between the two wires.

- Plans: on Monday we will take the two gusset rings from the spare package since we will need them for a week to build the package spacers. For that, first we will replace the top gusset with a Lexan sheet, then will take the package out of the mounting table and put it upside down using some strong-back. Then we will replace the bottom gusset. After we are done with the spacers we will re-install the gusset rings in the same way. The spare package will go for testing in 126 after we are done with the third package there. The spacers will be installed between the packages and then we will do the practicing with the mock-up.

Engineering

- Bill started working on the fixture for the scintillators needed at the Hall for triggering: it is not a problem at all and will consists of unistruts along the cart attached to the cart frame.

- Bill was asked by Bruce Lenzer (suggested by Glen) to include the mock-up cabling in their QA plan, since this will verify that the cable density is correct and that there's enough space to the CDC and BCAL. Bill will write a short report after this exercise.

Full electronics tests

- Beni now has the software to sparsify the data from the fADC in the ROC processors. Now he is taking long runs over the night and some results are shown in the E-log entries 110, 111. There you can see the raw signals (one plot per fADC), the profiles of the strips from all the planes connected (4 cells so far), and the wire positions as reconstructed from the strips. The reconstruction method is simplified so far, that's why you see a lot of noise in between the wire positions.

- Two fADC channels are not working properly and there are four strips where the problem is in the FDC. In the previous version of these plots there were ~10 missing strips. Vlad and Lubomir fixed all of them by unplugging/plugging the cards and sometimes releasing a little bit the screws on the clamps. Several of the channels were next to a manifold, but those were fixed. After that two strips re-appeared as problematic and two new strips showed problems. Beni suggested to spray the connectors with a cleaner to see if this will help.

- Plans: the new VXS crate is in 126 and Chris and Nick will install it soon. Next week when Cody is back Beni will take 12 more fADC125s. Then we will connect the last two cells with signal cables and will be able to take data from all the channels.

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