title: A simple methodology for characterization of germanium coaxial detectors by using Monte Carlo simulation and evolutionary algorithms.
abstract: The determination in a sample of the activity concentration of a specific radionuclide by gamma spectrometry needs to know the full energy peak efficiency (FEPE) for the energy of interest. The difficulties related to the experimental calibration make it advisable to have alternative methods for FEPE determination, such as the simulation of the transport of photons in the crystal by the Monte Carlo method, which requires an accurate knowledge of the characteristics and geometry of the detector. The characterization process is mainly carried out by Canberra Industries Inc. using proprietary techniques and methodologies developed by that company. It is a costly procedure (due to shipping and to the cost of the process itself) and for some research laboratories an alternative in situ procedure can be very useful. The main goal of this paper is to find an alternative to this costly characterization process, by establishing a method for optimizing the parameters of characterizing the detector, through a computational procedure which could be reproduced at a standard research lab. This method consists in the determination of the detector geometric parameters by using Monte Carlo simulation in parallel with an optimization process, based on evolutionary algorithms, starting from a set of reference FEPEs determined experimentally or computationally. The proposed method has proven to be effective and simple to implement. It provides a set of characterization parameters which it has been successfully validated for different source-detector geometries, and also for a wide range of environmental samples and certified materials.
authors.affiliation: Departamento de Física, Universidad de Las Palmas de Gran Canaria, 3501 Las Palmas de Gran Canaria, Spain; Instituto Universitario de Sistemas Inteligentes y Aplicaciones Numéricas en la Ingeniería, Universidad de Las Palmas de Gran Canaria, 3501 Las Palmas de Gran Canaria, Spain. Electronic address: jgarcia@dfis.ulpgc.es.
authors.forename: J G
authors.initials: JG
authors.lastname: Guerra
authors.affiliation: Departamento de Física, Universidad de Las Palmas de Gran Canaria, 3501 Las Palmas de Gran Canaria, Spain.
authors.forename: J G
authors.initials: JG
authors.lastname: Rubiano
authors.affiliation: Instituto Universitario de Sistemas Inteligentes y Aplicaciones Numéricas en la Ingeniería, Universidad de Las Palmas de Gran Canaria, 3501 Las Palmas de Gran Canaria, Spain.
authors.forename: G
authors.initials: G
authors.lastname: Winter
authors.affiliation: Departamento de Física, Universidad de Las Palmas de Gran Canaria, 3501 Las Palmas de Gran Canaria, Spain.
authors.forename: A G
authors.initials: AG
authors.lastname: Guerra
authors.affiliation: Departamento de Física, Universidad de Las Palmas de Gran Canaria, 3501 Las Palmas de Gran Canaria, Spain.
authors.forename: H
authors.initials: H
authors.lastname: Alonso
authors.affiliation: Departamento de Física, Universidad de Las Palmas de Gran Canaria, 3501 Las Palmas de Gran Canaria, Spain.
authors.forename: M A
authors.initials: MA
authors.lastname: Arnedo
authors.affiliation: Departamento de Física, Universidad de Las Palmas de Gran Canaria, 3501 Las Palmas de Gran Canaria, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Tejera
authors.affiliation: Departamento de Física, Universidad de Las Palmas de Gran Canaria, 3501 Las Palmas de Gran Canaria, Spain.
authors.forename: J M
authors.initials: JM
authors.lastname: Gil
authors.affiliation: Departamento de Física, Universidad de Las Palmas de Gran Canaria, 3501 Las Palmas de Gran Canaria, Spain.
authors.forename: R
authors.initials: R
authors.lastname: Rodríguez
authors.affiliation: Departamento de Física, Universidad de Las Palmas de Gran Canaria, 3501 Las Palmas de Gran Canaria, Spain.
authors.forename: P
authors.initials: P
authors.lastname: Martel
authors.affiliation: Departamento de Física Aplicada, Universidad de Huelva, Campus de Excelencia Internacional del Mar (CEIMAR), 21071 Huelva, Spain.
authors.forename: J P
authors.initials: JP
authors.lastname: Bolivar
mesh_terms: D000465:Algorithms; D002138:Calibration; D005857:Germanium / Q000737:chemistry*; D009010:Monte Carlo Method; D011834:Radiation Monitoring / Q000191:economics / Q000295:instrumentation / Q000379:methods*; D011848:Radioactive Pollutants / Q000032:analysis*; D011868:Radioisotopes / Q000032:analysis*; D013051:Spectrometry, Gamma / Q000191:economics / Q000295:instrumentation
chemical_list: D011848:Radioactive Pollutants; D011868:Radioisotopes; D005857:Germanium
keywords: Characterization germanium detectors; Differential evolution; Efficiency calibration; Gamma-ray spectrometry; Monte Carlo method