Gamma-Ray Sensor Using YAlO3(Ce) Single Crystal and CNT/PEEK with High Sensitivity and Stability under Harsh Underwater Conditions

Abstract

A new gamma-ray sensor, which could be employed in harsh underwater conditions, was developed using YAlO3(Ce) single crystal and carbon nanotube reinforced polyetheretherketone (CNT/PEEK). The sensor is compact, highly sensitive and stable, by providing real-time gross counts and an accumulated spectrum for fresh, saline, or contaminated water conditions. The sensor was tested in a water tank for quantification of the limit of detections. The Φ51 × 51 mm2 YAlO3(Ce) crystal exhibits a nearly perfect proportionality with a correlation of over 0.999 in terms of light yield per energy and possesses a high energy resolution. The chemically stable CNT/PEEK window material further enhances the detection efficiency by minimizing the background counts from penetrating gamma-rays. Data timeliness was obtained for regulation-based minimum detectable activity targets within 300 s. For a source-detector distance of up to 300 mm in water, the gross counts demonstrate the existence of radionuclides (Cs-137 and Co-60), owing to their higher efficiency (max. ~15 times) than those of the photopeak counts. Such differences between efficiency values are more likely in water than in air because of the high density of water, resulting in an increased build-up of scattered photons. The proposed sensor is suitable for autonomous underwater systems.

Investigation to design, fabricate, and integrate a mobile radiation monitoring system in ocean

“…Figure 7 illustrates the variation of the measured dose rate at various distances with a 137 Cs radioactive source in the air. The curve describing the variation in the number of counts on different distances shows remarkable similarities to that obtained in the study [14].…”

A Novel Portable Gamma Radiation Sensor Based on a Monolithic Lutetium-Yttrium Oxyorthosilicate Ring

“…Recently, the development of crystal materials and photoelectric sensing technologies has completely changed the key components of portable gamma radiation detectors [ 9 , 10 , 11 ]. Lutetium-yttrium oxyorthosilicate (LYSO) is a scintillation crystal with efficient radiation detection characteristics, such as short decay time and high light yield [ 12 ].…”