videbaks's blog

8/4/2021
The new GG have been setup and calibrated, and is getting ready for tests.

Time provided a document for the tuning of GG in 2016 and with information how it is now setup.
comments from TIM

For run 18 we used the new GG system. That is where we had the 1.43us settling time. However, since then I increased the slew so the settling time is now over 2us.

I beleive for the outer sectors the faster settling time was not too much of an issue because of the pedestal subtraction method that is used, but for the new inner sectors, the initial tur on noise was a bit large.

Yes, the settling time is about the same for inner and outer.

The propgation delay from when the gated grid card receives trigger from TCD to when the output changes at the grid end is about 400ns.

7/26/2021
Tim had found issues with the crate and it as decided to go to the new GG.
We should device a testing pan. For reference I added some of the e-mails of relevance from Jan/Feb 2019 where the issue was first found.
See here

1/31/2021
It was decided to go back to old GG driver

1/30/2021
Summary and plots of some early cosmics data

Summary in e-mail on 1/29/2021
mostly it is seen for tb 36-40 in the inner sector, and 20-23 in the inner. But there are some that are very different e.g sector 2 has noise in tb 50-60 (3 peaks)
sector 4 near 50 and 60
sector 12 at 40 but also at 60
sector 17 somewhat similar.

Had all the noise from the driver been consistent over all inner sectorI think we could have gone on with some simple masking which is the first ~4-5 time bins of the inner sector but as some really deviate a lot I would also lean towards going back to the old GG for run21- with the condition that this get investigated well ahead of run-22 where the higher rates are really useful.

Last thought is the observation that in general, but not for all sectors the outer sector response
is mostly good with only some noise around ch 22 , and only rarely big enough to give rise to cluster.

Concluding we like to ggo back to old GG
-- should revisit new GG much ahead of run, and run with full system even without GAS to see
noise response and fix issues.

Sector 1 Inner charge vs. timebin
Gating pulses at tb ~52,52,60,65 and neg at the start of 40