Dosimetry and calorimetry performance of a scientific CMOS camera for environmental monitoring

Aguilar-Arevalo, Alexis, Bertou, Xavier, Canet, Carles, Cruz-Pérez, Miguel Angel, Deisting, Alexander, Dias, Adriana, D’olivo, Juan Carlos, Favela-Pérez, Francisco, Garcés, Estela A, Muñoz, Adiv González, Guerra-Pulido, Jaime Octavio, Mancera-Alejandrez, Javier, Marín-Lámbarri, Daniel José, Montero, Mauricio Martinez, Monroe, Jocelyn, Paling, Sean, Peeters, Simon J M and others, (2020) Dosimetry and calorimetry performance of a scientific CMOS camera for environmental monitoring. Sensors, 20 (20). a5746 1-30. ISSN 1424-8220

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This paper explores the prospect of CMOS devices to assay lead in drinking water, using calorimetry. Lead occurs together with traces of radioisotopes, e.g.,210 Pb, producing γ-emissions with energies ranging from 10 keV to several 100 keV when they decay; this range is detectable in silicon sensors. In this paper we test a CMOS camera (OXFORD INSTRUMENTS Neo 5.5) for its general performance as a detector of X-rays and low energy γ-rays and assess its sensitivity relative to the World Health Organization upper limit on lead in drinking water. Energies from 6 keV to 60 keV are examined. The CMOS camera has a linear energy response over this range and its energy resolution is for the most part slightly better than 2%. The Neo sCMOS is not sensitive to X-rays with energies below ∼ 10 keV. The smallest detectable rate is 40 ± 3 mHz, corresponding to an incident activity on the chip of 7 ± 4 Bq. The estimation of the incident activity sensitivity from the detected activity relies on geometric acceptance and the measured efficiency vs. energy. We report the efficiency measurement, which is 0.08(2)% (0.0011(2)%) at 26.3 keV (59.5 keV). Taking calorimetric information into account we measure a minimal detectable rate of 4 ± 1 mHz (1.5 ± 0.1 mHz) for 26.3 keV (59.5 keV) γ-rays, which corresponds to an incident activity of 1.0 ± 0.6 Bq (57 ± 33 Bq). Toy Monte Carlo and Geant4 simulations agree with these results. These results show this CMOS sensor is well-suited as a γ-and X-ray detector with sensitivity at the few to 100 ppb level for210 Pb in a sample.

Item Type: Article
Keywords: X-ray detection, commercial CMOS cameras, dosimetry, gamma detection, lead in drinking water, lead-210, scientific CMOS sensor, world health organisation
Schools and Departments: School of Mathematical and Physical Sciences > Physics and Astronomy
SWORD Depositor: Mx Elements Account
Depositing User: Mx Elements Account
Date Deposited: 24 Nov 2020 09:26
Last Modified: 24 Nov 2020 09:30

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