Clarify the scope of the FLUKA black-hole pitfall and add the electron weights

This updates the scoring pages after review by the FLUKA expert.

- The MFT black-hole paragraph now states which O2 versions are affected, and that the official ALICE FLUKA and FoCal A-side calculations are not.
- FLUKA low-energy neutron transport needs FlukaParam.lowNeutron=true, which is off by default in o2-sim.
- The NIEL weight file now carries the RD50 electron table; its source is cited.

https://rd50.web.cern.ch/NIEL/
AliceO2Group/AliceO2#2877

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Author: sawenzel

docs/scoring/README.md

@@ -170,9 +170,14 @@ electron (11) — and they are applied like this:
 | everything else | zero |
 
 Outside the tabulated energy range the weight is clamped to the first or last
-tabulated value. The file shipped with O2 has no electron table, so electrons
-and positrons carry no damage weight; against FLUKA, which weights them, this
-costs about half a percent in the inner tracker.
+tabulated value. The electron table covers 0.3 to 200 MeV (Summers et al.,
+IEEE Trans. Nucl. Sci. 40 (1993) 1372, as compiled by RD50), so electrons below
+0.3 MeV get the lowest tabulated weight. O2 versions from before October 2026
+ship the file without the electron table; there e± weigh nothing, which is
+about half a percent of the inner-tracker n eq.
+
+The four tables are the RD50 compilation by A. Vasilescu and G. Lindström,
+https://rd50.web.cern.ch/NIEL/.
 
 The consequence for a comparison: **do not filter the NIEL scorer down to
 neutrons, protons and pions.** FLUKA's `SI1MEVNE` weights every hadron and

docs/scoring/flukacomparison.md

@@ -82,9 +82,11 @@ So per event: `fluka_value * total_weight / nevents` against
 - **Same kinematics.** Generate once with `--noGeant`, then replay the same
   file in both engines with `-g extkinO2 --extKinFile o2sim_Kine.root`.
   Otherwise the comparison also contains the generator.
-- **Low-energy neutrons.** FLUKA transports neutrons down to thermal energies
-  by default. Geant4 does not, unless an HP physics list is used and the
-  neutron cut is lowered:
+- **Low-energy neutrons.** Whenever neutrons below 20 MeV matter, which is the
+  case for any 1 MeV n eq map, switch low-energy neutron transport on in both
+  engines. In FLUKA this is `FlukaParam.lowNeutron=true`; it is off by default
+  in `o2-sim`, and setting `FlukaParam.scoringFile` also switches it on. In
+  Geant4 use an HP physics list and lower the neutron cut:
   `G4.physicsmode=kFTFP_BERT_HP_optical;SimCutParams.lowneut=true;GlobalSimProcs.CUTNEU=5.e-12`.
 - **Optical photons.** Geant4 produces and transports Cherenkov photons in the
   FT0; FLUKA in the ALICE setup does not. They show up in any unfiltered
@@ -107,8 +109,10 @@ Check this in every FLUKA run directory before you trust a map:
 grep -c "ASSIGNMAT       -1.0" flukaMat.inp   # 0 when healthy
 ```
 
-This affected the ten MFT PEEK support disks in ALICE 2 and pulled the FLUKA
-fluence in the barrel down by up to a factor two — for a long time this was read
-as a physics disagreement between the two codes. The geometry is fixed by
-giving the support volume a name of its own; make sure your O2 version has that
-fix.
+In ALICE 2 this happened to the ten MFT PEEK support disks, which lowered the
+FLUKA fluence in the barrel by up to a factor two. The name clash exists in O2
+from February 2020 ([AliceO2 PR 2877](https://github.com/AliceO2Group/AliceO2/pull/2877)) until September 2026, when the support
+volume got a name of its own (`4f9072579a`). It concerns only TFluka runs with
+an O2 version from that period and the MFT in the geometry. The official ALICE
+FLUKA calculations predate it and are not affected, and neither are the FoCal
+calculations on the A side.