Update ZDC LYSO Pedestal Sigma Parameter #1541
Conversation
github-actions
bot
added
topic: calorimetry
JiaJunHuang120000
temporarily deployed
to
github-pages
GitHub Actions
Inactive
Capybara summary for PR 1541 |
src/detectors/ZDC/ZDC.cc
Outdated
| @@ -33,7 +33,7 @@ extern "C" { | |||
| .capADC = 32768, | |||
| .dyRangeADC = 2000 * dd4hep::MeV, | |||
| .pedMeanADC = 400, | |||
| .pedSigmaADC = 3.2, | |||
| .pedSigmaADC = 0.2, | |||
There was a problem hiding this comment.
Basically, here you claim that 15-bit ADC can not resolve your pedestal. That is unrealistic.
There was a problem hiding this comment.
The current parameters cause issues for O(5-10 MeV) photons. 5-10 MeV photons may be a reasonable lower limit target for the LYSO.
We do not have expected noise estimates yet. But the current version has a threshold cut at 4*3.2 = 12.8 ADC channels, which is a deposited energy per tower of about 0.8 MeV. For LYSO, a 0.8 MeV deposit corresponds to a light yield of about 25,000 photons.
If we don't want to decrease to pedestal width from 3.2 ADC channels, we maybe can decrease the dynamic range of the LYSO from the current 2 GeV value.
There was a problem hiding this comment.
The current numbers should have been implemented following request of the Simulation group to DSC's. Ideally, the simulations reflect performance of the detector as can be constructed, not performance that is desired. Is it possible to get these updated parameters endorsed by DSCs?
My original comment about ADC is not meant to imply that ADC noise defines the floor, but to point out that ballpark numbers aren't feasible and that one could seek for a higher resolution ADC if the noise is less than one unit. Reducing dynamic range will not help for noise defined by the sensor.
There was a problem hiding this comment.
Sounds good. Thanks. We'll chat with the DSC about the parameter values.
|
|
JiaJunHuang120000
temporarily deployed
to
github-pages
GitHub Actions
Inactive
|
bschmookler
temporarily deployed
to
github-pages
GitHub Actions
Inactive
| @@ -64,7 +64,7 @@ extern "C" { | |||
| { | |||
| .sectorDist = 5.0 * dd4hep::cm, | |||
| .localDistXY = {50 * dd4hep::cm, 50 * dd4hep::cm}, | |||
| .dimScaledLocalDistXY = {50.0*dd4hep::mm, 50.0*dd4hep::mm}, | |||
| .dimScaledLocalDistXY = {5, 5}, | |||
There was a problem hiding this comment.
Likely not going to work since you rely on buggy behavior fixed in #1598.
### Briefly, what does this PR introduce? This PR updates the digitization parameters for the SiPM-on-Tile ZDC. The current default parameters place a zero-suppression threshold at 40 ADC channels. With a 15-bit ADC with dynamic range of 800 MeV, this is a cut at 0.98 MeV (~ 2 MIPs). We see that this has an impact on the energy reconstruction for single-particle simulations. This PR changes following values: ``` ADC Capacity = 16-bit (65536 channels) DynamicRange = 1000 MeV (0.015 MeV per ADC channel) pedSigmaADC = 2 thresholdFactor = 3.0 ``` These parameters are realistic. The HGROC ASIC can have a capacity of 16-bits; a high-energy photon shower can leave up to 800-1000 MeV in a single channel; and a zero-suppression cut of 6 ADC channels (0.2 MIPs) will allow studies of threshold cuts in the 0.2-0.5 MIP range. The above changes have been discussed with the SiPM-on-Tile DSC lead, Miguel Arratia. ### What kind of change does this PR introduce? - [ ] Bug fix (issue #__) - [ ] New feature (issue #__) - [ ] Documentation update - [x] Other: Digitization parameters update ### Please check if this PR fulfills the following: - [ ] Tests for the changes have been added - [ ] Documentation has been added / updated - [x] Changes have been communicated to collaborators Discussed with @sebouh137 and M. Arratia ### Does this PR introduce breaking changes? What changes might users need to make to their code? No. ### Does this PR change default behavior? Yes, for SiPM-on-Tile ZDC Closes: #1541
Briefly, what does this PR introduce?
Correct ZDC LYSO pedestal sigma parameter to for accurate reconstruction of low energy photons. Currently each ADC channel correspond to 0.06 MeV, and with previous value of pedestal sigma towers with energy less than 0.08 MeV were removed. Now, towers with lower energy deposites are kept.
What kind of change does this PR introduce?
Please check if this PR fulfills the following:
Does this PR introduce breaking changes? What changes might users need to make to their code?
No.
Does this PR change default behavior?
Only in ZDC ECal.