KLF beamline meeting - September 19, 2024
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Agenda
- Announcements
- Detector rates simulations in GEANT4 (Richard)
- Updates from FLUKA simulations (Pavel)
- Engineering design progress (Tim)
- Any other business
Minutes
Present: Vitaly, Richard, Hovanes, Moskov, Pavel, Beni, Tim, Josh, Edy, Eugene, Mikhail, Igor, Sashi, Sean, Chris, Richard, Igal, Lubomir, Justin.
- Eugene announced that JLAB management is severely limiting the procurement until end of October due to budget constraints, including capital construction projects like K-Long.
- Pavel looked at the beam size and the spectra of the particle incident on the cryo-target using his FLUKA model.
- Vitaly asked if the rate of the low energy photons not shown on the picture is still high. Pavel's estimate for the photon rate on the target is still around 1.6GHz.
- Igor did not think it was worth looking at muons rates since they will not impact data and physics analysis. Igor also commented that Pavel should work on CPS design and not on the collimator cave. Eugene view was that we are evaluating all of the aspects of the beam after and KPT, and the rates of all particle types should be evaluated.
- The beam size without shielding wall after the PS detector is 12cm in diameter, while with a shielding wall with a 6cm aperture for the beam pipe the beam size at the target is about 6cm in diameter.
- Pavel suggested installing a collimator right in front of the target cart snug around the beampipe as we need to replace the PS shield wall with something else. The collimator would consist of a ~15cm layer of CuW followed by about 10cm borated polyethylene.
- Tim said that such a small collimator could be attached to the target cart and can easily be supported by the part of the platform under the target.
- Mikhail found suspicious that the beam pipe with the flanges would not clean up the neutrons. At this time, Pavel does not have details of the beam pipe, like the flanges, in his simulations.
- Hovanes pointed out that both Igor's MCNP6 simulations and Pavel's FLUKA simulations suggest on the order of ~30mrem/hr dose rate at the SC SiPMs, mostly from neutrons. Attenuating the neutron rate may help reduce the dose rate at the SiPMs, thus increasing the livetime of these SiPMs.
- Pavel also thought it might be good, for the radiological point of view, to remove the permanent magnet and PS magnet field. That way, the elliptical pipe inside the permanent magnet will not be a source of secondary particles reaching the target. Instead one could install a collimator in the cave so that there will be a collimated muon beam in the beampipe all the way to the photon beam dump. Mikhail though that this may not be feasible because of the problems with a large number of charged particles reaching the target and detectors. Pavel did not think there were other charged particles in the beamline other than muons, but he agreed that it may be problematic. But he thought it would be worth studying this option.