Fix bugs and code quality issues found in CRVResponse review

[Copilot]

Summary

Detailed code review of the CRVResponse module identified and fixed several bugs and code quality issues across 4 files.

Bug Fixes

1. Wrong logarithm base in SiPM after-pulse timing (MakeCrvSiPMCharges.cc)

The exponential distribution sampling for trap (after-pulse) times used log10() instead of log() (natural logarithm). The standard formula for exponential random variable generation is x = -lifetime * ln(U) where U is uniform(0,1). Using log10 produced a mean of lifetime / ln(10) ≈ lifetime / 2.303, making after-pulse times ~2.3× shorter than intended by the physical lifetime parameters.

2. Operator precedence bug in findScintillatorCerenkovBinReverse (MakeCrvPhotons.cc)

The expression (bin / nBetaBins*nZBins) % nYBins evaluated as ((bin / nBetaBins) * nZBins) % nYBins due to left-to-right associativity of / and *, instead of the intended (bin / (nBetaBins*nZBins)) % nYBins. This affected the reverse bin lookup used in diagnostics.

3. Cherenkov photon interpolation bug (MakeCrvPhotons.cc)

In GetAverageNumberOfCerenkovPhotons, the prevBeta/prevNumberPhotons values for linear interpolation were only updated on the first map iteration. For beta values beyond the second map entry, the function would incorrectly interpolate between the first entry and the matching entry, instead of between adjacent entries.

4. Wrong type for NZS flag (CrvDigitizer_module.cc)

crvDigiMC.IsNZS() returns bool but was stored in a double variable.

Code Quality Improvements

5. Removed dead code: Removed unused static int nPScintillation/nPCerenkov counters and their associated commented-out print statement in MakeCrvPhotons.cc.
6. Fixed misleading comments: Corrected swapped closing-brace comments in the nested SiPM/step/photon loops in MakeCrvPhotons::MakePhotons.
7. Fixed typo: "dublicate" → "duplicate" in CrvWaveformsGenerator_module.cc.
8. Improved error handling: Changed TFile open check from == NULL (which doesn't detect failed opens since new never returns NULL) to IsZombie() in MakeCrvSiPMCharges.cc.

[FNALbuild]

Hi @Copilot,
You have proposed changes to files in these packages:

• CRVResponse

which require these tests: build.

@Mu2e/fnalbuild-users, @Mu2e/write have access to CI actions on main.

📝 The author of this pull request is not a member of the Mu2e github organisation.

About FNALbuild. Code review on Mu2e/Offline.

[oksuzian]

@FNALbuild run build test

[FNALbuild]

⌛ The following tests have been triggered for 3dc2285: build (Build queue - API unavailable)

[ehrlich-uva]

All proposed changes can be accepted. Only point 3 will result in an insignificant change of the simulation results. Here are some additional comments.

1. This calculation is used for after-pulses, which were never turned on in our simulations.
2. This reverse lookup function is not used in our simulations.
3. This function is used for the simulation of Cerenkov photons, but the number of Cerenkov photons is small compared to the scintillator photons, and the difference in the number of Cerenkov photons introduced by this bug is also very small. So overall, this bug has only an insignificant impact on the number of photons.
4. This bug did not make a difference, since the NZS flag in CrvDigi is currently not checked anywhere.
5. It was used for debugging and can be removed.
6. These comments must have been switched by mistake.
7. Typo in comment.
8. It never caused any problems, but doesn't hurt to change.

[ehrlich-uva]

See my comments above.

[FNALbuild]

☀️ The build tests passed at 3dc2285.

Test	Result	Details
test with	✅	Command did not list any other PRs to include
merge	✅	Merged 3dc2285 at 5ec09f9
build (prof)	✅	Log file. Build time: 04 min 07 sec
ceSimReco	✅	Log file.
g4test_03MT	✅	Log file.
transportOnly	✅	Log file.
POT	✅	Log file.
g4study	✅	Log file.
cosmicSimReco	✅	Log file.
cosmicOffSpill	✅	Log file.
ceSteps	✅	Log file.
ceDigi	✅	Log file.
muDauSteps	✅	Log file.
ceMix	✅	Log file.
rootOverlaps	✅	Log file.
g4surfaceCheck	✅	Log file.
trigger	✅	Log file.
check_cmake	✅	Log file.
FIXME, TODO	✅	TODO (0) FIXME (0) in 4 files
clang-tidy	➡️	4 errors 100 warnings
whitespace check	✅	no whitespace errors found

N.B. These results were obtained from a build of this Pull Request at 3dc2285 after being merged into the base branch at 5ec09f9.

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