Minutes for LArSoft coordination meeting on Mar 12, 2019
Present | Lynn Garren, Robert Hatcher, Alex Himmel, Kyle Knoepfel, Saba Sehrish, Erica Snider|
Remote | Patrick Green, Diego Garcia-Gamez, Andrzej Szelc, Katherine Lato |
Release and Project status report [Erica Snider]
- v08_12_00 released on march 6
- this week updates to nutools, and no meerge requests so far
- Neext week:
- migration to root v6.16/00 - to fix an iorule problem
- will combine with migration to art 3.02
- Genie v3
- validation testing by MicroBooNE, once done will get sign off from other experiments
- LArTPC data overlay workshop
- LArSoft workshop 2019
- 1.5 days, dates TBD
- Tentative program - LArSoft introduction, Advanced computing techniques, dnd Long-term vision
- [Lynn] suggested to add a session patch releases
Conclusion:
A semi-analytic way of Simulating light [Andrzej Szelc]
- Introduces analytic model for light propagation
- Optical libraries size are very large (for DUNE and SBND, > 1 GB)
- problem for cvmfs, so moved to StashCache
- Does not provide timing information (though this is solved in LArSoft)
- Need to run a campaign of grid jobs every time a detector parameter changes
- For DUNE 1x2x6, segmenting the bars into sub-detectors makes it impossible to generate the library due to memory issues. Needed for the TDR
- DUNE needs realistic X-Arapuca supercell geometry for physics studies. SBND libraries also becoming cumbersome
- An alternate method for simulation of light to make things work
- Improved parameterization of photon arrival times for both VUV and visible light
- A semi-analytic model for predicting N hits based on position in the detector for direct VUV and reflected light coming off cathode
- Simulation of the VUV arrival times
- this work provides optimzation and extension of existing feature in LArSoft for the photon arrival time
- VUV arrival times change as function of distance due to Rayleigh scattering
- Index of refraction also changing rapidly across emission spectrum
- This needs to be taken into account
- Landau + exponential for short distances (< 300 cm)
- Landau for longer distances (> 300 cm(
- Visible arrival calculated as distance / velocity
- Smearing in times approximated as exponential (w cutoff)
- Semi-analytic modelling of light (direct)
- Calculate solid angle
- Functions for square and circular detectors
- No library needed, so avoid memory issues
- No issue from segmentation of bars into X-Arapuca supercells or windows
- Can scale to full size of DUNE
- Need correction due to Rayleigh scattering + reflections
- Detailed study of border effects on-going
- Corrections to direct light due to scattering
- Gaisser-Hillas functions fit well
- Based on ratio of solid angle calculation to full simulation as a function of angle from photo-detector
- Parameterize as function of angle and distance to photo-detector
- Show agreement with full simulation is better than for libraries
- Reflected light (visible)
- Created by TPB coated foils on cathode
- Calc cathode solid angle for VUV
- Correct for scattering using Gaisser-Hillas curves
- Detected photons from solid angle to optical detector (from foils)
- Parameterize corrections as function of angle, distance from cathode
- VU direct light results:
- there is no bias and performs better the photon librarries
- Performance for DUNE 1x2x6: also better than the optical libraries
- Should not be looking outside the range ( for range -500 < y < 500 cm)
- Most of the changes in larsim
- bulk of code is in LArG4/OpFastScintillatiton
- Improvement in the PhotonVisibility Serevice
- use pre-calculated values result in huge efficiency improvement
- discrepency introdiced by this is negligible ~0.1 ns
- the use of feature is off by default
- fcl configuration provided to enable optical library and time correction and also to enable nhits and time correction
- More improvements to the code: remove duplicated code
- Future improvements:
- is it worth splitting the photon counter module into two since it does too many things
- based on old LArG4 - for DUNE
- Testing
- DUNE CI tests
- ArgoNeuT and LArIAT ok
- ICARUS and MicroBooNE have some problem
- SBND failed. Wrong tag. Will re-check
- Almost ready to go (modulo the failing CI tests)
- Thread safety?
- Not
- Should be able to make it not a service (Photon visibility)
- Kyle raised some issues related to multi-threading
- Will address with the move to the new LArG4.
Conclusion
- This feature request was approved.
- larsim: feature/lightprop_ugr_mcr
- larana: feature/lightprop_ugr_mcr
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