Study based on cosmic trigger I've chosen reference run 42438 to look for bad channels, that was one of the most recent runs at the time. Bad channels were identified for run 42438 (SRC, PS). On individul channel histograms 4 histograms are shown. Top 2 are for channel in question and his another end. Bottom 2 histograms show channels on which first 2 channle would reflect after the cable swap. I looked on the channels in the scope and perhaps while shaking the cables fixed the problem with channel 18M11, because it disappeared in the next tun 42439 (SRC, PS). After that in special run 42446 cables with channels in question were swapped to check if the problem moves with the cable or stays with the channel (SRC, PS). I concluded that 1 channel 15M16 is a candidate for bad RS TDC module. That module was replaced and problem was fixed. After that run 42448 without cable swap was taken. So after this cosmic trigger study 2 channels were fixed and 2 channles have problems not associated with RS TDC.
Summary of cosmic trigger study
PS Run 42438 Bad channels before study
7P11 about 50% efficient problem moved with cable
15M16 about 30% efficient problem stayed with channel
module was replaced and problem fixed
16P02 second peak problem moved with cable
18M11 gigantic second peak. problem was cured by checking cable connections
PS Run 42448 Bad channels after study
Study based on rsmon trigger Same technique was utilized to look on rsmon triggers. I've chosen reference run 42448 to look for bad channels. IU added two channels 7P11 and 16P02 from cosmic study to the list. (SRC, PS). In special run 42449 with cables swapped to look if problem move with the cable or stayed with RS TDC channels. (SRC, PS).
Summary of rsmon trigger study
PS Run 42448 Bad channels before study
7P11 is OK in rsmon
1M14 about 10% efficient problem moved with cable
16P02 is OK in rsmon
23M18 dead problem moved with cable
To summarize there are 4 questionable channels problems with which are not
associated with RS TDC. I also looked on some of the in the scope.
| channel | rsmon trig | cosmic trig | oscilloscope |
|---|---|---|---|
| 7P11 | OK | about 50% efficient | did not look |
| 16P02 | OK | second peak | multiple peaks at the end of the signal |
| 1M14 | about 10% efficient | OK | did not look |
| 23M18 | dead | OK | discriminator generates a train of signals (about 1000) for each RSMON pulse. Length of train is about few microseconds. |
Here is the history of cable swaps:
june XX ---> someone swaped cables. Perhaps Peter and Bob around
June 6. Run 41907 (June 6) already has cables swapped.
I could not find quality runs prior to that.
July 31 ---> Jim Frank noticed 2 swapped cables and fixes them
August 2 ---> Dima notices one more swapped cable
---> I fix that cable and check all the cables.
(BTW this cable swap explaines why Kelvin fixed PMT 16P03
and in mysterious ways TDC 16P11 started to work)
---> I do not know how exactly CFM works, but perhaps we
need to copy rd_map.00003 to rd_map.00006
**** FILES ARE ALREADY IN $CAL_DB ******
rd_map.00003 0..41906 Cables plugged right
rd_map.00004 41907..42384 3 cables swapped
rd_map.00005 42385..42427 1 cable swapped
rd_map.00003 42428..inf Cables plugged right
In table rd_map.00004 Jim assumed that 2 cables were swapped, but Dima
noticed (and I confirm) there were actually 3 cables swapped. So I MODIFIED
rd_map.00004
Study of first 8 "double-peak" channels showed that they have missing bits. . This module was replaced and the problem disappeared.
Here is the summary of "bad channels" based on Sasha Artamonov's list. There is 1 problematic channel left. PS , kumac , hbook .
The problematic channels: ............................................................ sector | layer | end | diagnostic | notation ............................................................ 1, 3, 1 - strange peak 1M03 Fixed - TDC module replacement 1, 3, 2 - strange peak 1P03 Fixed - TDC module replacement 1, 4, 1 - strange peak 1M04 Fixed - TDC module replacement 1, 4, 2 - strange peak 1P04 Fixed - TDC module replacement 1, 5, 1 - strange peak 1M05 Fixed - TDC module replacement 1, 5, 2 - strange peak 1P05 Fixed - TDC module replacement 1, 6, 1 - strange peak 1M06 Fixed - TDC module replacement 1, 6, 2 - strange peak 1P06 Fixed - TDC module replacement 15,17, 1 - empty channel 15M17 (actually 16M21 - cable swap) Working OK 16,11, 2 - strange peak 16P11 (actually 16P03 - cable swap) Fixed July 31 by Kelvin Li 18,11, 1 - strange peak 18M11 about 10% efficient. 21, 4, 2 - empty channel 21P04 Fixed July 31 by Kelvin Li
For 18M11 Bipul said that HV adjustments are not necessary, So there is something else going on. Splitter?