Agenda

Preliminary IERR Report (Hovanes)
- Recommendations related to the beamline group (Hovanes)
- Input for IERR simulations (trigger & tracking) (Igor)

Minutes

Present: Igor, Eugene, Hovanes, Moskov, Vitaly, Tim, Beni, Sean, Sashi, Pavel, Richard, Marshall

There was an Intermediate Readiness Review last week for KLF during which physics analysis related topics were addressed. Members of KLF presented 12 talks to respond to the items listed in the charge of the review committee. We already received 12 recommendations that will need to be addressed by the next readiness review (ERR-2). The full report with the recommendations as well as the findings and comments will be released in a couple of weeks.

Hovanes announced that procurements for KPT have been temporarily suspended until all related concerns are addressed and the engineering design is modified if needed. Igor was disappointed by this decision as he thought that the KPT design was in a good shape. Eugene pointed out that due to the budget cuts the procurements at Jefferson Lab are currently limited to the items that are absolutely needed for near term operations. Procurement requests for items over $250 will need justified by the requester and then approved by the Physics Division.

Hovanes presented the six recommendations that he though were related to the beamline group. The beamline group will need to provide an input regarding the beamline design. Most of the uncertainties at this time were in the design of the beamline in the collimator cave and downstream which affect the kaon, neutron and low energy photon rates in the hall. These design parameters need to be finalized and then implemented in the beamline and the detector simulation software packages. The main part of the response to the review comments will be addressed at the KLF analysis meetings chaired by Sean.

Addressing the review comment about 128ns bunching, Moskov said that he plans to present a stronger physics case for the 128ns beam bunching to be presented to Patrizia.

Moskov also stated that KLF intends to build a new Start Counter. Eugene warned us that the design and construction status for this new detector will need to well advanced during the next ERR-2 in order to be able to get approved for installations. The next ERR-2 would need to happen sometime next summer for the KLF installations to be approved for the summer of 2026, meaning that the time for the design and construction of the new Start Counter is short.

Richard showed his recent simulations of the GlueX detector response to the nominal KLF beam with the current design of the collimator cave. His plots correspond to 1.2ms of 5μA electron beam. This would mean that the low energy photon rate at the cryo-target is about 4.5 GHz.

Start Counter paddles are expected to see 0.4 hits per 64ns bunch burst per counter. This corresponds to 12 SC hits per bunch. With 16MHz bunch rate, this would amount to 6.4 MHz counting rate per SC paddle. This is pretty high rate.

The CDC and FDC seem to have pretty large occupancies as well. CDC is expected to see one hit per 64ns burst , and FDC is expected to see 4 to 6 hits per FDC layer. This could cause problems to tracking efficiencies especially considering the long pulse length distribution for CDC. Some of the drift chambers could even be unable to hold voltage at these level of occupancies, according to Richard.

BCAL occupancies look better, the hit number distribution versus the layer number suggests that most of the hits over thresholds come from the target area. BCAL occupancy per 64ns bunch is not high, below 2 hits for whole layer. FCAL (which did not include new ECAL) also has low occupancy.

Some of the TOF are expected to see 1 hit per 64ns bunch burst creating high background. This can be a problem not only for the rates but also for the PMTs as raising the thresholds will not help with the drawn anode current.

Beni suggest using a Lexan sheet to protect the TOF counters. Richard would like a volunteer to place one in the GlueX geometry.

Eugene suggested to repeat the same simulations with an empty target to see if the high rates in CDC and TOF come from the target or the beam halo. Richard will also to try to identify the origin of the hits from the output files.

The current version of the GEANT4 model of the KPT assembly uses 90/10 tungsten/copper compound with a density of the tungsten of 19.2 g/cm $^{3}$ . Hovanes suggested to reduce the tungsten density such that it matches Tim's number of approximately 16.5 g/cm $^{3}$ density for the compound material. Tim checked his notes and said that the compound density can vary between 16.5 g/cm $^{3}$ and 17 g/cm $^{3}$ .

Igor asked Richard to summarize what he thinks are the main issues that need to be looked into. According to Richard the detectors that could cause KLF problems are SC (#1), DCs(#2), and TOF (#3).