KLF beamline meeting - February 6, 2025
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Agenda
- Announcements
- FLUKA simulation update (Pavel)
- KL rate estimates from SLAC data (Hovanes)
- Any other business
Minutes
Present: Moskov, Josh, Edy, Hovanes, Pavel, Sean, Mikhail, Vitaly, Marshall, Eugene, Igor, Beni
- Moskov asked Edy about beam tests for KLF. Edy said that two beam tests are being planned within the next six months for KLF: one invasive to other halls test that includes the whole machine; and another one only includes injector.
- Hovanes showed the updated parameters for the beamline in the collimator cave and the main hall that resulted after the meeting with engineers and designers.
- Vitaly asked if the thermal analysis has been done for 20% radiator since there is a possibility that some of the flat vertical surfaces may become hot spots because of the wider beam spot. Hovanes said that although Pavel did FLUKA simulations with a 20% radiator, no thermal analysis have been done for this condition.
- Pavel implemented the recent changes of the beam line into the FLUKA geometry, including the fat beam pipe inside the target assembly.
- His new estimate of the KL rate is 8.2 KHz. He also showed the momentum dependence of the rates for particles in the beam.
- Pavel also estimated 1MeV-neutrons equivalent doses in the hall near the target after 10000 hours of running. The dose where SC SiPMs would be located will see 1010 cm-2 or less of 1MeV equivalent neutrons.
- Vitaly asked what was the "critical dose" for SiPMs, he thought it was 1014 cm-2. Beni and Pavel thought the effects of radiation damage would be manifest well below that dose. Pavel and Hovanes pointed out there is an article that studies the radiation damage of SiPMs for Gluex. (Later note by Hovanes: the SiPMs dark rate will increase by a factor of ~5 after 109 cm-2 1MeV-neutrons equivalent dose, based on that NIM article).
- Pavel also showed 2D-maps of particles fluences in the hall with the updated geometry.
- Mikhail asked if Pavel has ever done simulation with deuterium target since the neutron rate would be higher with deuterium. Pavel said he had not done it so far since there had not been a request to simulate it.
- Hovanes looked at the SLAC paper on KL electroproduction. He fitted the SLAC data with a function of Ee, PK, and θK to estimate the kaon rate for KLF kinematics.
- The fits results indicate 3.8 KHz kaons per second, which is about factor of 2 less than FLUKA predictions. Also the rate fall-off with momentum is more steep in the fit prediction that in the FLUKA prediction.
- Hovanes will work to improve the fits and to estimate the uncertainties for the kaon rates for KLF.
- Pavel said that he sees a sharp change of the θK dependence of the kaon yields near θK=2 degrees. Since data that Hovanes fits does not contain points below θK=2 degrees and Hovanes essentially extrapolates the rates with a linear function, this could cause underestimation of the kaon rates for KLF kinematics. Hovanes plans to take a look at the θK of the rates in FLUKA and try to include it as constrains in the fit.
- Mikhail said that JLAB property people responded to York inquiries. They are trying to figure out how to deal with the insurance of the KFM related equipment while at JLAB.
- Hovanes asked if the basic layout of KFM parts in the hall is known. Mikhail thought that he had already sent that information to Tim, but he will double check it.
- We ran out of time, Hovanes' presentation will have to wait for the next meeting.
- The next meeting will be on February 13 .