The CLAS12 Low Threshold Cherenkov detector

Journal Article · 09 January 2020 · Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment

DOI: https://doi.org/10.1016/j.nima.2020.163420 · OSTI ID:1615768

Ungaro, M.; Anderson, D.; Asryan, G.; Antonioli, M. A.; Bonneau, P.; Burkert, V. D.; Christo, S.; Cook, M.; Duran, B.; Eng, B.; Hoebel, A.; Insley, D.; Jacobs, J.; Joosten, S.; Leffel, M.; Lemon, T.; McMullen, M.; Meziani, Z. E.; Miller, R.; Rojas, P. B. ; Sharabian, Y. G.; Yegneswaran, A.

The CLAS Cherenkov threshold gas detector was instrumental for electron identification in the Hall B 6 GeV era at Jefferson Lab. The detector's scope has been modified for the new CLAS12 spectrometer to identify pi(+) and pi(-) for momenta greater than 3.5 GeV, thus becoming a Low Threshold Cherenkov Counter (LTCC). This was accomplished with a refurbishment of the gas container, its windows, mirrors, Winston light collecting cones, and photomultipliers. The design, construction, and performance of the refurbished LTCC are described. The lightweight mirrors and Winston cones have been re-surfaced with a highly reflective coating, the 5-in photomultiplier tube entrance windows have been treated with p-terphenyl to enhance the ultraviolet response, and the gas volume has been expanded to increase the thickness of the radiator gas and correspondingly the number of photoelectrons in the response signal. The LTCC response calibration has been performed on the single photoelectron signals, and the system efficiencies and response functions have been measured.

• Research Organization: Argonne National Laboratory (ANL), Argonne, IL (United States)
• Sponsoring Organization: USDOE; USDOE Office of Science - Office of Nuclear Physics - Isotope Development and Production for Research and Applications (IDPRA)
• Contributing Organization: CLAS Collaboration
• Grant/Contract Number: AC02-06CH11357; AC05-06OR23177
• OSTI ID: 1615768
• Journal Information: Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment, Journal Name: Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment Journal Issue: C Vol. 957; ISSN 0168-9002
• Publisher: ElsevierCopyright Statement
• Country of Publication: United States
• Language: English