Performance of the Two Aerogel Cherenkov Detectors of the JLab Hall A Hadron Spectrometer

Journal Article · Thu Jan 01 00:00:00 EST 2009 · Preprint to be distributed

OSTI ID:956234

Marrone, Stefano; Wojtsekhowski, Bogdan; Acha Quimper, Armando; Cisbani, Evaristo; Coman, Marius; Cusanno, Francesco; De Jager, Cornelis; De Leo, Raffaele; Gao, Haiyan; Garibaldi, Franco; Higinbotham, Douglas; Iodice, Mauro; LeRose, John; Macchia, D; Markowitz, Pete; Nappi, E; Palmisano, F; Urciuoli, Guido; van der Werf, I; XIANG, Hong ; Xiang, Hong; XIANG, Hong; Xiang, Hong; Zhu, Lingyan

We report on the design and commissioning of two silica aerogel Cherenkov detectors with different refractive indices. In particular, extraordinary performance in terms of the number of detected photoelectrons was achieved through an appropriate choice of PMT type and reflector, along with some design considerations. After four years of operation, the number of detected photoelectrons was found to be noticeably reduced in both detectors as a result of contamination, yellowing, of the aerogel material. Along with the details of the set-up, we illustrate the characteristics of the detectors during different time periods and the probable causes of the contamination. In particular we show that the replacement of the contaminated aerogel and parts of the reflecting material has almost restored the initial performance of the detectors.

• Research Organization: Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-060R23177
• OSTI ID: 956234
• Report Number(s): JLAB-PHY-08-885; arXiv:0810.4630; DOE/OR/23177-0535; TRN: US1004959
• Journal Information: Preprint to be distributed, Journal Name: Preprint to be distributed
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
CHERENKOV COUNTERS
COMMISSIONING
CONTAMINATION
DESIGN
HADRONS
PERFORMANCE
SILICA
SPECTROMETERS