sPHENIX HCal discussion

[Edward Kistenev <kistenev AT bnl.gov>]

Dear All,

here is what I have in my personal ELOG plus contributions from Igor Romanov (part time IT specialist at UNIPLAST). Igor may correct me somewhat.  If corrections are essential then I will update this mail.

All data are on the SSD disk in the DAQ computer (HP Pavillon), already copied to the drop box which belongs to GSU and then to RCF. They are root trees (mppc and tc), the first are the data from CAEN copied SBND Cosmic Ray  Tracker Front-End Board, the second is from thermocouples built into tester by Steve Boose and connected to tester soft by J.Haggerty (thank you).

Edward

We began with small tiles and it was complete disaster. It was only during our (JL/EK) second trip to UNIPLAST when we finally understood that the whole picture was dominated (saturated) by ambient light from all kinds of sources (although we were really carefull) and wrong trigger setting.

10/27/2018    Small tiles

Configuration (stack numbers are bottom to top)

(1)

Stack      1                                 2                    3                   4                    5                   6                    7                    8                    9                               10

Tile         new (BT)   s21.001.003  s22.002.006  s21.001.004  s22.002.007  s23.044.119  s24.045.121  s23.044.120  s24.045.122  s27.048.127 net(TT)

Trigger tiles (BT and TT are both new small, made a lot of runs, understood nothing, recorded almost nothing, removed small tiles, tried something new

Tile                .120                   BT                  TT               .122               .121              .119               .007               .004              .006                            .003

then all large tiles (at that moment all tiles are large from new samples including BT & TT which were wrapped tiles, other three not yet wrapped)

Tile                   BT                  A                       B                   C                    -                    -                     -                     -                   -                               TT                 mppc_2018-10-29_10-53.root

Tile                   TT                  A                       B                   C                                                                                                                                          BT                 mppc_2018-10-29_11-50.root

Same as above, run repeated   _______________________________________________________________________________________________________mppc_2018-10-30        

Same as above with an extra tedlar sheet between A&B____________________________________________________________________________________mppc_2018-10-30_09-38-42.root

I think at this time we were really frustrayed and tried all kinds of tricks like trigger tiles wrapped and unwrapped, god knows what. Besides JL and EK were at MEPHI, it was work over the phone.

mppc_2018_10-29-11-50.root

mppc_2018-10-30_08-41-40.root

mppc_2018-10-30_09-38-42.root

10/31/2018   (JL & EK at UNIPLAST). We had a lot of discussions trying to find the solution. In the mean time UNIPLAST finished the set of 24 pilot tiles for HOuter so we were better prepared to do systematic studies then before MEPHI meeting.

Stack  position   1   2   3   4   5     6     7     8     9    10

ADC                   0   2   3   8   9   10   11   12   13      1  

Tile                     1   2   3   4   5     6     7     8     9    10          Tiles 9 & 10 are small for scaling between small & large tiles. Tiles in ADC channels 0/1 are used for triggering

Signal shape in ADC 1  has no signs of peaking (similar to how it looked at BNL).

Switched trigger to channels 2/3 (large tiles). Expected rate ~20hz

Trigger rate at threshold 400 is 2hz (too low - muons at BNL and in Vladimir are different - should we move to the roof?).

mppc_2018-10-31_11-47-07_t400.root

Same configuration, threshold 380 (before recording - multiple tests with trigger moved and different thresholds went without recording).

Improved picture quality, suppressed low amp. noise, increased rate;

13:15   mppc_2018-10-31_11-47-07_t380.root

Next few files are for a different thresholds in the same configuration. Trigger saturates ~350-340 then rates begins growng anew. Rate at 350 - 15hz, at 340 - 30hz (pictures still fine but peak around "0" starts dominating.

NOTE: intermediate files are lost - current implementation would not allow to save files twice in the same root session), manual data saving (SaveAs) into file with ~correct time stamp requires same done to tc tree (cumbersome) and may end with empty file. For now - we need to kill the run and start the new one to save file with time stamp corresponding to the beginning of the run.

In summary we failed to get reasonable data triggering with threshold of 400 on signals from tiles in channels 0/1

After a lot of playing with black cloth, door closing, isolating tiles from LED lights inside readout box etc we finally reached ~stable running conditions 

We ended up at threshold of 350, results in ~30% of hits in pedestals in trigger channels.  We finally got correct rate and correct signal shape. Then it was lost to faulty breaker somewhere in the building. It was sparking for a few hours then burned out.

14:00

New configuration: 10 tiles (5 wrapped/unwrapped pairs, used only pairs not too different in shape to avoid whole concoction falling apart, went through with triggers from different pais (two tiles of different configuration (that was ~mistake, needed better arrangement)

mppc_2018-10-31_14-07-54.root   10 tiles (5 pairs), trigger on ADC pair in 2-3. Configuration is as below. Needs to pay attention to attempt to keep Bl/W sequence in stack addresses and pair sequence in ADC channels.  

Stack #              10         9         8           7          6         5            4         3           2        1

ADC                    1       13        12         11        10         9            8         3           2        0

Tile              p1-bl     p5-w     p5-bl    p4-w    p4-bl    p3-w     p3-bl    p2-w    p2-bl   p1-w

17:21 mppc_2018-10-31_17-20-21.root   Trigger 2/3

17:32 mppc_2018-10-31_17-32-04.root   Trigger 8/9

11/1/2018
10 tiles are removed from tile tester, properly labeled, and positioned back into their original positions:
01 (00) - B27.72.187 wrapped
02 (02) - B29.77.192 not wrapped
03 (03) - B29.76.191 wrapped
04 (08) - B31.81.196 not wrapped
05 (09) - B31.80.195 wrapped
06 (10) - B30.79.194 not wrapped
07 (11) - B30.78.193 wrapped
08 (12) - B25.69.184 not wrapped
09 (13) - B25.68.183 wrapped
10 (01) - B27.73.188 not wrapped

4 runs  600 s each  (threshold 350):
7:01 mppc_2018-11-01_06-59-29.root   Trigger 10/11

7:13 mppc_2018-11-01_07-13-06.root   Trigger 12/13

7:30 mppc_2018-11-01_07-29-21.root   Trigger 0/1

7:44 mppc_2018-11-01_07-43-07.root   Trigger - or of all 5 pairs 

11/2/2018
Final run of the week with BNL participation: 3600 s (threshold 350):
mppc_2018-11-02_08-40-30.root - Тrigger on  0, 1 coincidence.

Hopefully sometime early this coming week UNIPLAST will build its own Black Box which will address issues of light proliferation (I really hoped to see tester arriving to UNIPLAST in the black box). Then we'll continue with measurements planned to show that tester is stable and (probably) may run with only minimal attention from operator.