C1-1 investigation for Stave 4
Beatrice Mandelli
CERN, University of Oslo
Tayfun Ince
Max-Plack Institut fur Physik
FE-I4 Meeting - July 14, 2013
1
What happened until now
- Week-end of Cosmic Scan. Everything fine
- Suddenly on Monday afternoon C1-1 started to not work
- Digital Scan: ok
- Analog Scan: empty
- The same behaviour have been noticed for the first scans during the reception test
- Different test have been performed without effect:
- Changed global threshold, TDAC/FDAC step sizes, discriminator current... different tunings...
- Picture of the module shows some dust/material/soldering near the pads 6, 7, 8, 9
- Test performed to check if there is a short.
- After we found out the possible short, we tried to
clean the area between 6 and 7
- New test performed to check the intervention output
Beatrice Mandelli
2
July 15, 2013
Before the intervention
Test on C1-1- and C1-2 (as refeence) following Mauriceʼs suggestions
- Test behavior of FdacVbn and Amp2Vbpf
-
Set Amp2Vbpf from 50 to 0 for both chips.
Set FdacVbn from 20 to 0 for both chips.
Set FDACs to 7 for both chips:
ToT Test (10k reference). 10.42 +/- 1.79 C1-1. 5.253 +/- 1.03 C1-2
Set FDACs to 4 for both chips:
ToT Test (10k reference). 11.4 +/- 1.82 C1-1. 5.293 +/- 0.988 C1-2
Set FDACs to 10 for both chips:
ToT Test (10k reference). 6.2 +/- 1.132 C1-1. 5.27 +/- 1.03 C1-2
Tests
perfor
me
and c
old te d at warm
mpera
ture
In a healthy chip setting FdacVbn to
zero will make the TOT not change
with FDAC value
Short between pads 6 and 7
Beatrice Mandelli
3
July 15, 2013
Before the intervention
Test on C1-1- and C1-2 (as refeence) following Mauriceʼs suggestions
- Test behavior of Amp2Vbp and Amp2Vbpf
-
Set FdacVbn back from 0 to 20 for both chips.
Set Amp2Vbpf back from 0 to 50 for both chips.
Analog Test works.
Set Amp2Vbpf from 50 to 250 for both chips.
Set Amp2Vbp from 85 to 0 for both chips.
Analog Test empty.
Tests
perfor
med a
and c
tw
old te
mpera arm
ture
- Test behavior of Amp2Vbp and Amp2Vbn
-
Set Amp2Vbp from 85 to 0 for both chips.
Set Amp2Vbn from 79 to 0 for both chips.
Analog Test empty.
Set Amp2Vbp back from 0 to 85 for both chips.
Set Amp2Vbn back from 0 to 79 for both chips.
- Analog Test works.
Beatrice Mandelli
4
July 15, 2013
What has been done
Mechanically cleaned the intermediate space between pads 6 and 7 of C1-1 on
Stave 4, using a probe needle. Cleaning wasn't extremely successful, but we first
went to trying to operate the module
Beatrice Mandelli
5
July 15, 2013
After the intervention
- Set FdacVbn from 20 to 0. Set Amp2Vbpf from 50 to 0. Set fdac to 4.
- ToT test (target charge 10000). C1-1 ToT 7.32 +/- 1.82. C1-2 ToT 4.0 +/- 1.025.
- Set fdac from 4 to 10
- ToT test (target charge 10000). C1-1 ToT 7.2 +/- 1.95. C1-2 ToT 3.948 +/- 1.019.
It seems that the short is not here
anymore!
Box o
pen. O
nly LV
on
Box c
losed
. ~ 10
°C
LV on . HV and
Beatrice Mandelli
6
July 15, 2013
After the intervention
- ToT test (target charge 10000). C1-1 tot 6.366 +/- 2.2. C1-2 tot 5.283 +/- 1.02.
- Set fdac from 10 to 4.
- ToT test (target charge 10000). C1-1 ToT 6.35 +/- 2.2. C1-2 ToT 5.3 +/- 1.01.
- Set FdacVbn to 20. Set Amp2Vbp from 85 to 0. Set Amp2Vbf from 50 to 250.
- Analog Empty
- Set FdacVbn to 20. Set Amp2Vbp to 0. Set Amp2Vbf from 250 to 50. Set
Amp2Vbn from 79 to 0
- Analog Empty
- Set FdacVbn to 20. Set Amp2Vbp 85. Set Amp2Vbf from 250 to 50. Set
Amp2Vbn 79.
~ 10°
C. HV
and L
V on
It seems that the short is not here
anymore!
Beatrice Mandelli
7
July 15, 2013
After the re-work
- Set FdacVbn to 0. Set Amp2Vbf to 0.
- Analog bad or empty
~ -20
°C. H
- Set FdacVbn to 20. Set Amp2Vbf to 50.
V and
LV on
- Analog Good
- Set FdacVbn from 20 to 0. Set Amp2Vbpf from 50 to 0. Set fdac 4 or 10
- Still Analog bad or empty
Beatrice Mandelli
8
July 15, 2013
Summary
Before the intervention:
- In general C1-1 was “randomly” working.
- After several tests, we conclude there was a short between 6 and 7
- C1-1 analog scan worked when we set FdacVbn and Amp2Vbp to 0 both at
warm and cold temperature
After the intervention:
- At warm temperature:
- C1-1 analog scan works
- C1-1 analog scan works when we set FdacVbn and Amp2Vbp to 0
- At cold temperature:
- C1-1 analog scan works
- C1-1 analog scan doesnʼt work when we set FdacVbn and Amp2Vbp to 0
Beatrice Mandelli
9
July 15, 2013