Francesco Gonnella NA62 Collaboration meeting Washington DC, U.S.A. KTAG status report Francesco Gonnella NA62 Collaboration meeting Washington DC, U.S.A. 29 August 2017

Hardware developments Second WIENER crate installed to ease TEL62 maintenance 3 TEL62 + 4 splitters per crate The boards can now safely be removed from the crate Modification for H2 operation: N2 flushing for CEDAR diaphragm motor installed Intrinsic safety barrier protecting CEDAR diaphragm limit switches installed H2 safety testing Mock H2 filling/emptying performed New flame retardant shroud installed ADCs monitor Wiener crate 2 voltages No under voltage was observed during ktag 4 tel62 reset Francesco Gonnella - University of Birmingham 29 August 2017

TEL62 firmware reload Board reloads Many board reloads of KTAG TELs in 2017 A metal shield put in front of crate The number of reloads did not change significantly Francesco Gonnella - University of Birmingham 29 August 2017

Hardware status High voltage Some PMTs voltage above threshold (~905 V) Affected boards are not always the same The first 8 channels of the board are involved Power-cycling the HV crate always solves the problem Saleve-side low voltage PSU Ethernet port broken No longer remotely controllable Broken y-position sensor CERN experts replaced it Dead and noisy channels are reported on the right 2 noisy channels 4 dead channels Francesco Gonnella - University of Birmingham 29 August 2017

Radiation at the KTAG station A straw radiation monitoring was installed in KTAG area Cosmic rate (CR) is 0.4 Hz per straw At KTAG station, rate with no beam is ~3Hz (6 times CR) During interspill the rate goes up to ~20 Hz (50 times CR) Position Value (with 18E11 on T10) Interspill Lower KTAG Crate ~45 kHz ~0.38 kHz Upper KTAG Crate Upstream concrete ~70 kHz KTAG box ~430 kHz ~50 KHz Francesco Gonnella - University of Birmingham 29 August 2017

Pressure scan 2017 Run number 7391 Beam Intensity on T10 = 17.6E11 Diaphragm = 1.5 mm Pressure scan from 1.8 bar to 1.7 bar (around kaon peak) Francesco Gonnella - University of Birmingham 29 August 2017

Pressure scan 2015 Run number 3143 Full Pressure scan from 1.6 bar to 2 bar Diaphragm = 1.5 mm Pressure @K peak: ~1.75 bar Francesco Gonnella - University of Birmingham 29 August 2017

Pressure scan: 2015 vs 2017 Pressure value set for Kaons: 1.735 bar Kaon rate = 22.5 MHz (from computations in NA62Reco) Better K/p separation at 1.5 mm Diaphragm 2015 2017 Francesco Gonnella - University of Birmingham 29 August 2017

Saleve-Jura Asymmetry 2017 spatial alignment After Pressure scan the diaphragm aperture was reduced down to ~1.3 mm, while keeping the alignment The final CEDAR vessel reference positions are reported in tab X [mm] Y [mm] Diaphragm [mm] Up-Down Asymmetry Saleve-Jura Asymmetry Number of hits -0.232 -0.756 1.529 -0.052 -0.021 20.25 -0.233 -0.758 1.292 -0.054 -0.023 20.20 Francesco Gonnella - University of Birmingham 29 August 2017

KTAG efficiency MB 29 August 2017 Francesco Gonnella - University of Birmingham 29 August 2017

KTAG time resolution MB 29 August 2017 Francesco Gonnella - University of Birmingham 29 August 2017

Francesco Gonnella - University of Birmingham TDCB errors Stoyan Francesco Gonnella - University of Birmingham 29 August 2017

Conclusions and future plans Hardware is good KTAG is up and running according to specs Efficiency is bla better than 2015 Time resolution is blabla Short-term plans for board reload To see if thermal neutrons are causing them, a Cd foil shield can be put around crates Radiation monitors can be used to find suitable position for crates: On a platform few meters above their current position At the same height but farther downstream in TCC8: to GTK3 to LAV5 What else? Francesco Gonnella - University of Birmingham 29 August 2017