Enhanced UV light detection using a p-terphenyl wavelength shifter

Journal Article · Tue Jul 25 00:00:00 EDT 2017 · Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment

DOI:https://doi.org/10.1016/j.nima.2017.06.050· OSTI ID:1374045

Joosten, Sylvester J. ^[1]; Kaczanowicz, Ed ^[1]; Ungaro, Maurizio ^[2]; Rehfuss, Melanie L. ^[1]; Johnston, K. ^[1]; Meziani, Zein -Eddine ^[1]

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1. Temple Univ., Philadelphia, PA (United States)
2. Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

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.

• Research Organization: Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
• Sponsoring Organization: USDOE
• Grant/Contract Number: FG02-94ER4084
• OSTI ID: 1374045
• Alternate ID(s): OSTI ID: 1549620
• Report Number(s): JLAB-PHY-17-2529; DOE/OR/23177-4196; arXiv:1611.03467; PII: S0168900217307039; TRN: US1702549
• Journal Information: Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 870, Issue C; ISSN 0168-9002
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
Cherenkov detector
p-Terphenyl
Wavelength shifter
PMT
JLab
CLAS