Difference between revisions of "Minutes-4-24-2014"

From GlueXWiki
Jump to: navigation, search
m (Text replacement - "/halldweb1.jlab.org/" to "/halldweb.jlab.org/")
 
(11 intermediate revisions by 2 users not shown)
Line 10: Line 10:
 
# 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: Eugene, Fernando, Dave, Nick, Simon, and Lubomir.
+
Participants: Curtis, Naomi (CMU), Eugene, Bill, Mike, Dave, Beni, Chris, Nick, Simon, and Lubomir (JLab).
  
−
== FDC testing status ==
+
== Gas system ==
  
−
- Final results from the scope test (done by Anatoly) of all the channels with FDC in its final position are in the spreadsheet linked above. About 50 strip channels (0.4% of all the strips) are identified as having some kind of problem, almost all of them related to the conductive tape issue. As compared to the scope tests done after the first "final" insertion almost nothing changed, i.e. the re-insertion didn't create additional problems.  
+
- Dave: The pressure tests of the gas system started, we found one bad flow controller that Bill is going to send back for repair. Scott connected the CDC and the FDC mixing vessels so that, without one flow controller, we still can supply gas, the same mixture, for both detectors. The fact that CDC and FDC are going to use slightly different gas mixtures is not important in the moment (Curtis).  
  
−
- Comparing with the Beni's DAQ results: all the problematic channels from the scope test can be identified in the Beni's histograms as deviating from the neighboring channels, except several channels that are probably dominated by a noise. In addition to the 50 bad channels from the scope test, there are about 30 new bad channels in the Beni's results. Lubomir looked with a scope into 10 of these channels and didn't find any problem. Fernando and Chris did similar test with a scope and concluded for most of the channels the signals at the input of the fADCs are good. However, according the Beni the problematic channels move with the cable. Therefore Fernando suspects it might be the front panel on the fADC that prevents the cable connector from completely going in the fADC connector. They will investigate this.
+
- It turned out that we have industrial gas (both Ar and CO2) ordered and used now for the tests of the gas system. An option would be to put filters and continue using it till we get the right gas. Eugene: we should stop using it right away, or when we are done with the pressure tests. Dave prepared documents (attached above) for the flushing of the gas system and the detectors, but it should wait till we get the right gas. We have not decided at this meeting if we need gas filters in addition to what is already in the system, but Bill is looking into different options.  
 
   
 
   
−
== Engineering ==   
+
== CDC status ==   
  
−
- Last week the FDC was moved downstream by about 5mm (info from Josh) to make space for the CDC, without releasing the FDC cables on the face of the magnet. According to Casey they just looked to make sure there's no tension on the cables. Then stoppers were installed on both FDC and CDC side on the rail. On Tuesday survey of the FDC in its final position was done. Important is that they were able to see all the 16 reflectors installed on the periphery of the packages. Before that the CDC was surveyed: it is off by 7mm downstream with respect to the nominal position (Eugene).
+
- Mike: the CDC cooling has been installed but the temperature oscillates (Nick) by about 5-6degC. Bill thinks there are easy ways to fix this and he is looking into this. Before the cooling system was installed, Nick measured the temperature on the regulators and it was ~60degC which (according to Fernando) means about 100degC on the silicon. This is not acceptable and the LV should not be kept for more than 1 hour without cooling.
 +
 +
== DAQ ==
  
−
- The gas system is next on the list, the OSP for the pressure testing will be signed soon and beginning of next week the test will be done. Dave is working on the procedure (files attached) for testing and flushing the whole gas system which is suppose to happen by the end of next week. Yesterday the mass flow controller that was used temporary for the FDC was needed to complete the gas system and was replaced with a rotameter that somehow consumes much more gas. Fernando: flushing with alcohol will require also OSP. That's why the flushing will be done for now without alcohol, later it will be added.  
+
- Cody is modifying the fADC125 firmware to make the beginning and the width of the time window parameters. The numbering of the fADC channels now starts from 0. Beni wants to make sure all this works before he starts testing the CDC.
  
−
- Elton is working on the ESAD document and we are responsible for the FDC and the gas sections there. The first version is attached above (pages 14-15).
+
- Now every detector has its own account to be used with the DAQ. So far Beni was running the DAQ on his own account.
−
Fernando: the HV and LV hazards will be described in the electronics section, so we just have to refer to that section.  
+
 
 +
- Beni was reading the FDC strips for more than a week. The results are linked above: two plots for the up- and down-stream cathodes in each a column represents one package. Since there's no trigger even 1Hz noise (similar to the cosmics rate) is visible. Therefore we should try using a trigger, the easiest for now will be to use the scintillator paddles below the magnet (Eugene).
  
−
- At the beginning of the week the Fluorinert level was very low and we put the last gallon we had, in the chiller and even after that the level is much below the "low" mark. We suspect some leakage and will need the Fluorinert sniffer again to check at least the outside connections. Dave ordered another container (20kg) with Fluorinert. 
 
−
 
 
== Electronics ==
 
== Electronics ==
  
−
- Fernando: the LV supplies are now regulating the sense voltage, i.e. the voltage on the patch panels. The numbering convention for the electronics channels should be followed, i.e. first channels is 0.
+
- Some of the cables with bad strip channels that were tested with a scope and looked OK, have changed in the latest Beni's results. This may indicate something is wrong with the 3M connectors. Since we are sure about this for at least 5-6 connectors, Chris is going to look at them tomorrow.     
 +
 
 +
== ESAD ==
 +
 
 +
- Beni and Lubomir worked on the CDC/FDC sections of the Hall D ESAD document, linked above. We discussed the safe pressure limits for the two detectors: should be between 0 and 200 Pa and under-pressure is even more dangerous. Actually CDC has never been operated at more than ~100Pa but if we want to have 3 gas exchanges per day the pressure will be higher than that. Beni: important is to make sure the input bubbler can limit the pressure in the detectors.
 +
For the FDC the pressure difference between the cells should be <30Pa. LV hardware interlock for the CDC: can be connected to the airflow system directly (like the fan), while the PLS system will measure the temperature and stops the LV.  
  
−
- The FDC ground is now connected directly to the clean ground while the CDC ground is not connected. There's no ground connection for the mesh: it might be difficult but not impossible, to connect a ground cable on the side of the mesh. Soon the ground panel on the face of the magnet will be attached to the clean ground and the FDC, CDC, and the mesh grounds will be attached to that panel.
+
- Gas sytem text is not ready. Possible hazards: the alcohol in the gas makes it combustible (Bill), high pressure section (above 15 psi).
−
   
+
−
== CDC update ==
+
  
−
- Due to the big overlap in equipment, procedures, software (gas system, pre-amps, fADC, HV, LV modules, DAQ, testing software) with the CDC and the experts present at this meeting, Fernando proposed and everybody agreed that this meeting is the right place to give updates also on the CDC activities.
+
== FDC cathode scan ==
  
−
- Nick and two techs finished the connections of the signal cables to the CDC. Now in principle one can apply LV on the pre-amps and Beni can look at the pedestal widths with the mini-DAQ to check the cable connectivity. Before that the cooling needs to be finished and make temperature measurements on the pre-amps. After the test of the gas system, in about 10-14 days, one can start flushing the CDC.
+
- Lubomir showed new results (picture linked above): the gaps are now NOT in between the foils, or strip #48 and #144, BUT at #44 and #149. The latter are the places where the Kapton tape starts/ends. The pitch in the side foils is 5.01mm while 5.00mm in the middle foil. As a result of these changes the deviations from the nominal are much smaller than before, at most +/-100 microns. Now both, the right and the left edges are used in the analyses. Somehow the right edge shows smaller variations. It is not clear at all why in the middle foil the pitch didn't change after the tensioning.  
  
−
-->
+
- When looking at all measured points along the gaps between the strips one can recognize that some areas are much more scattered than the rest, which indicates problems with the measurements: either bad contrast due to the coper or Kapton tape, or some other systematics. Bill will look if we can re-scan the cathode at least partially with the JLab CMM machines.

Latest revision as of 06:05, 1 April 2015

April 24, 2014 FDC meeting

Agenda

  1. Gas system [1],[2] (Dave, Beni)
  2. CDC status (Beni, Mike)
  3. DAQ [3], [4] (Beni)
  4. Electronics (Chris, Nick)
  5. Experimental Safety Assessment Document HallD_ESAD (Lubomir, Beni)
  6. FDC cathode scan [5] (Bill, Lubomir)
  7. Other

Instructions for Bluejeans meeting connection

FDC meeting ID: 290664653

Minutes

Participants: Curtis, Naomi (CMU), Eugene, Bill, Mike, Dave, Beni, Chris, Nick, Simon, and Lubomir (JLab).

Gas system

- Dave: The pressure tests of the gas system started, we found one bad flow controller that Bill is going to send back for repair. Scott connected the CDC and the FDC mixing vessels so that, without one flow controller, we still can supply gas, the same mixture, for both detectors. The fact that CDC and FDC are going to use slightly different gas mixtures is not important in the moment (Curtis).

- It turned out that we have industrial gas (both Ar and CO2) ordered and used now for the tests of the gas system. An option would be to put filters and continue using it till we get the right gas. Eugene: we should stop using it right away, or when we are done with the pressure tests. Dave prepared documents (attached above) for the flushing of the gas system and the detectors, but it should wait till we get the right gas. We have not decided at this meeting if we need gas filters in addition to what is already in the system, but Bill is looking into different options.

CDC status

- Mike: the CDC cooling has been installed but the temperature oscillates (Nick) by about 5-6degC. Bill thinks there are easy ways to fix this and he is looking into this. Before the cooling system was installed, Nick measured the temperature on the regulators and it was ~60degC which (according to Fernando) means about 100degC on the silicon. This is not acceptable and the LV should not be kept for more than 1 hour without cooling.

DAQ

- Cody is modifying the fADC125 firmware to make the beginning and the width of the time window parameters. The numbering of the fADC channels now starts from 0. Beni wants to make sure all this works before he starts testing the CDC.

- Now every detector has its own account to be used with the DAQ. So far Beni was running the DAQ on his own account.

- Beni was reading the FDC strips for more than a week. The results are linked above: two plots for the up- and down-stream cathodes in each a column represents one package. Since there's no trigger even 1Hz noise (similar to the cosmics rate) is visible. Therefore we should try using a trigger, the easiest for now will be to use the scintillator paddles below the magnet (Eugene).

Electronics

- Some of the cables with bad strip channels that were tested with a scope and looked OK, have changed in the latest Beni's results. This may indicate something is wrong with the 3M connectors. Since we are sure about this for at least 5-6 connectors, Chris is going to look at them tomorrow.

ESAD

- Beni and Lubomir worked on the CDC/FDC sections of the Hall D ESAD document, linked above. We discussed the safe pressure limits for the two detectors: should be between 0 and 200 Pa and under-pressure is even more dangerous. Actually CDC has never been operated at more than ~100Pa but if we want to have 3 gas exchanges per day the pressure will be higher than that. Beni: important is to make sure the input bubbler can limit the pressure in the detectors. For the FDC the pressure difference between the cells should be <30Pa. LV hardware interlock for the CDC: can be connected to the airflow system directly (like the fan), while the PLS system will measure the temperature and stops the LV.

- Gas sytem text is not ready. Possible hazards: the alcohol in the gas makes it combustible (Bill), high pressure section (above 15 psi).

FDC cathode scan

- Lubomir showed new results (picture linked above): the gaps are now NOT in between the foils, or strip #48 and #144, BUT at #44 and #149. The latter are the places where the Kapton tape starts/ends. The pitch in the side foils is 5.01mm while 5.00mm in the middle foil. As a result of these changes the deviations from the nominal are much smaller than before, at most +/-100 microns. Now both, the right and the left edges are used in the analyses. Somehow the right edge shows smaller variations. It is not clear at all why in the middle foil the pitch didn't change after the tensioning.

- When looking at all measured points along the gaps between the strips one can recognize that some areas are much more scattered than the rest, which indicates problems with the measurements: either bad contrast due to the coper or Kapton tape, or some other systematics. Bill will look if we can re-scan the cathode at least partially with the JLab CMM machines.

Retrieved from "https://halldweb.jlab.org/wiki/index.php?title=Minutes-4-24-2014&oldid=65709"