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This content will become publicly available on July 25, 2018

Title: Enhanced UV light detection using a p-terphenyl wavelength shifter

Here, UV-glass photomultiplier tubes (PMTs) have poor photon detection efficiency for wavelengths below $$300\,\text{nm}$$ due to the opaqueness of the window material. Costly quartz PMTs could be used to enhance the efficiency below $$300\,\text{nm}$$. A less expensive solution that dramatically improves this efficiency is the application of a thin film of a p-terphenyl (PT) wavelength shifter on UV-glass PMTs. This improvement was quantified for Photonis XP4500B PMTs for wavelengths between $$200\,\text{nm}$$ and $$400\,\text{nm}$$. The gain factor ranges up to 5.4 $$\pm$$ 0.5 at a wavelength of $$215\,\text{nm}$$, with a material load of $$110\pm10\,\mu\text{g}/\text{cm}^2$$ ($$894\,\text{nm}$$). The wavelength shifter was found to be fully transparent for wavelengths greater than $$300\,\text{nm}$$. The resulting gain in detection efficiency, when used in a typical Cherenkov counter, was estimated to be of the order of 40%. Consistent coating quality was assured by a rapid gain testing procedure using narrow-band UV LEDs. Based on these results, 200 Photonis XP4500B PMTs were treated with PT for the upgraded low-threshold Cherenkov counter (LTCC) to be used in the CEBAF Large Acceptance Spectrometer upgraded detector (CLAS12) at the Thomas Jefferson National Accelerator Facility.
Authors:
 [1] ;  [1] ;  [2] ;  [1] ;  [1] ;  [1]
  1. Temple Univ., Philadelphia, PA (United States)
  2. Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
Publication Date:
Report Number(s):
JLAB-PHY-17-2529; DOE/OR/23177-4196; arXiv:1611.03467
Journal ID: ISSN 0168-9002; PII: S0168900217307039; TRN: US1702549
Grant/Contract Number:
FG02-94ER4084
Type:
Accepted Manuscript
Journal Name:
Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment
Additional Journal Information:
Journal Volume: 870; Journal Issue: C; Journal ID: ISSN 0168-9002
Publisher:
Elsevier
Research Org:
Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; Cherenkov detector; p-Terphenyl; Wavelength shifter; PMT; JLab; CLAS
OSTI Identifier:
1374045