Characterisation of radiation field for irradiation of biological samples at nuclear reactor--comparison of twin detector and recombination methods

Abstract

Central Laboratory for Radiological Protection is involved in achieving scientific project on biological dosimetry. The project includes irradiation of blood samples in radiation fields of nuclear reactor. A simple facility for irradiation of biological samples has been prepared at horizontal channel of the nuclear reactor MARIA in NCBJ in Poland. The radiation field, composed mainly of gamma radiation and thermal neutrons, has been characterised in terms of tissue kerma using twin-detector technique and recombination chambers.

Simplified Bayesian method: application in cytogenetic biological dosimetry of mixed n + γ radiation fields

“…From physical measurements, it was known that the field consisted mainly of gamma rays and thermalized fission neutrons. To determine the total dose components, the twin detector method and recombination method were used (Golnik et al 2013). The dose fraction recommended as the contribution of gamma rays to total tissue kerma was 0.92 ± 0.02.…”

The Monte Carlo Method of Mixed Radiation Field Dose Assessment in the Cytogenetic Biodosimetry

“…The curves describe the dependence of the dicentric frequency found in analysed blood samples on the absorbed dose (for a specific source of radiation). Doseeffect curves are obtained by irradiating peripheral blood samples from several donors with different doses (which takes place in strictly controlled experimental conditions, such as dose rate, measured by physical equipment [14]) and then examining the frequency of dicentrics in isolated blood lymphocytes.…”

“…Calibration of the constants was done based on blood samples irradiated in channel H8 of the Maria Reactor, located in the National Centre for Nuclear Research (NCBJ), Świerk-Otwock, Poland. All parameters of the radiation beam are described in detail in the paper by Golnik et al [14]. Additionally, reference data (Table I) [5,7] was provided by the Central Laboratory for Radiological Protection (CLOR), Warsaw, Poland, which analysed and assessed the blood samples through meth-ods of biological dosimetry.…”

Calculated neutron energy dependence of the dose-response of large recombination chamber

“…The most popular method for determination of H*(10) with recombination chamber is based on determination of saturation current (i sat ) and recombination index of radiation quality RIQ, denoted as Q4 [2]. The RIQ is derived [2][3][4] from the measurements of ion collection effi ciency at a specially chosen polarizing voltage, so it expresses the amount of ion recombination, which depends on local ion density.…”