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Release and project report
Discussion
Alex Himmel: Regarding laracorealg#13 (closest TPC to photo-detector), believes the oustanding questions (what questions the geometry needs to answer) has been resolved
Contact the author (Gianluca Petrillo) about the status
Tom Junk reported excessive mem usage reading older files containing recob::Track with newer releases.
Found when reading recob::Track v13 (in the root schema evolution versioning system) with recob::Track v17
Whenever root's schema evolution occurred, saw very large memory leak
Has been reported to root, and the root maintainers have a solution
Will require new root version
Until then, expect this memory problem to appear
Will provide an update on this at a future LCM
Muve (Wei Mu): Algorithms for ions and photons calculation
Context
Two larg4 frameworks: Legacy, Refactored
Three sep algorithms:
Separate, NEST, Correlated
Noted two instances of Separate algorithm embedded in in legacy, one in larsim/ElectronDrift, the other in larsim/LegacyLArG4
Algorithms in photon fast simulation
Legacy
calls IonizationAndScintillation instances in LArG4 module
Chooses alg via ISCalculation + LArG4Parameters
Fast sim PD response by OpFastScintilation instance according to PhotonVisibilityService
Refactored
Dedicated IonAndScint module
Calc N ions and photons at each energy deposit
Choose alg via ISCalc + InputTag
PDFastSim module
Generate PD response according to GAN (previously discussed)
The Separate algorithm
Calc N ions based on recomb model + ion yield from LArG4Parameters
Calc N photons based on Particle type, scint yield from LArProperties
Calculated separately
The Correlated algorithm
New. Developed after refactored LArG4
Considers anti-correl between ion and photons due to electron-ion recomb
Uses either Box recomb model, or a saturation model
NEST
Slightly different between legacy and refactored LArG4
NestAlg (legacy), NESTLAr (refactored)
Considers anti-correl Box model / Birks law
In refactored, only uses params recorded in EnergyDeposit, and only supports LAr
In Legacy, supports Ne, Ar, Kr, Xe + uses parameters beyond EnergyDeposit
Goth work identically for LAr
An issue with the Separate algorithm
N photons in refactored ~15% more than produced in legacy
Observed for configs protodunev7_photonvisibilityservice, + protodune_v7_refactored_nowires.gdml
Legacy considers EM saturation effect
Uses Birks law (G4EmSaturation) to calc visible energy deposit at a step
Then calcs N photons based on universal scint yield
Should we port saturation method?
Discussion
Alex: just drop support for separate
Laura: Also a problem reported w NEST
Muve: has been fixed
Alex: this is all NEST v1. Mike Mooney said v2 was in the works.
Muve: have not seen this yet.
Laura Paulucci Marinho: LArQL: a model for LAr ionization and scintillation
Work with F. Cavana, F. Marinho, D. Totani
Motivation
Lack of well defined mech for Scint light emission in LAr
ProtoDUNE PDS data analysis results sensitive to some no\t yet adequately sim effects of light from recomb
Goals and limits
Only separate and NEST were available at the time
Started from there to see what to improve
Unitary model for ionization and scintillation light as function of energy dep and E field
Noted the energy deposition range that is of interest. (see slides...)
Know that free ionization and scint light anti-correlated
Also know light reduction at low E field and low dE/dx due to electrons escaping recombination
LArQL
3 experimental params
ionizations per unit E
excitations / ionizations
fraction of escaping electrons
LY obtained from free charge yield
Modify Birks charge model correcting for escaping and additional electrons at lower E-field range
At high E-field, Birks recovered
Described model
Comparing to data
Works well for charge and scint (ProtoDUNE??)
Showed apparent consistency w MicroBooNE
LArSoft implementation
Use ISCalc
Noted that correlated model appeared when working on this implementation
So could add this as a correction to the recombination model
Discussion
Seems a reasonable approach
MicroBooNE: might be interested in this, since it improves data / MC agreement
Will need to contact people in MicroBooNE. Erica will facilitate this
Would require updating their production branch. Changes to the head do not affect them.