KLF beamline meeting - February 27, 2025

Agenda

• Announcements

• K_L-rates from SLAC data (Hovanes)

• FLUKA simulations (Pavel)

• Updates on GEANT4 simulations (Richard)

• Any other business

Minutes

Present: Eugene, Moskov, Vitaly, Mikhail, Igor, Edy, Pavel, Hovanes, Tim, Sean, Stuart, Beni

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• Mikhail announced that Take Saito from RIKEN won a ~$1M grant for hyper-nuclear stations in KLF. The grant is for 5 year. It should cover the procurements and labor for both emulsions and germanium segments.

• Moskov suggest that the collaboration needs to figure out the strategy on how to approach the upcoming readiness review also suggested that we have a morning meeting that would be at a time that Japanese collaborators could attend.

• Edy said that the run is postponed until March 21st. The accelerator division is working hard to start the run at that date. The injector is broken, so the bleed-through tests are very unlikely to be done before the run, as previously planned.

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• Hovanes presented his updates on K-long rate evaluations using SLAC data.

• SLAC data at non-zero angles are fitted, then extrapolated to zero degrees and interpolated to 12 GeV beam energy.

• He uses parameterisation for the kaon absorption in the materials.

• Using his simple model, Hovanes checked that 40cm is close to optimal for Be target length and that improvements will not result in significant kaon rate improvement as we are in the pretty flat are of the rate maximum.

• Kaon rates Hovanes expects during KLF is 3.1 KHz , based on the SLAC data and his fit and extrapolation procedure.

• Pavel commented that there are kaon produced at the forward angles that are not properly taken into account by Hovanes' procedure.

• Hovanes also ran his procedure on SLAC pseudo data simulated by Pavel using FLUKA. The projection for KLF rate using these pseudo SLAC data instead of SLAC data is 5.4 KHz versus 8.2KHz from FLUKA prediction for KLF.

• Adjusting kaon absorption cross section by a 20% decrease at all kaon momenta would make the pseudo data extrapolation match FLUKA KLF prediction, according to Hovanes. The real SLAC data prediction with 20% lower absorption cross sections for kaons would be about 4.6 KHz.

• Moskov pointed out that the integrated rate is not the only metrics that defines the FOM for the experiments in the proposal.

• Vitaly asked for a kaon rate estimate for P_K=0.44 GeV/c for his analysis.