Fluence to Hp(3) conversion coefficients for neutrons from thermal to 15 MeV

Abstract

The recent statement on tissue reactions issued by the International Commission on Radiological Protection in April 2011 recommends a very significant reduction in the equivalent dose annual limit for the eye lens from 150 to 20 mSv y(-1); this has stimulated a lot of interest in eye lens dosimetry in the radiation protection community. Until now no conversion coefficients were available for the operational quantity Hp(3) for neutrons. The scope of the present work was to extend previous evaluations of H*(10) and Hp(10) performed at the PTB in 1995 to provide also Hp(3) data for neutrons. The present work is also intended to complete the studies carried out on photons during the last 4 y within the European Union-funded ORAMED (optimisation of radiation protection for medical staff) project.

Electron, Photon, and Neutron Dose Conversion Coefficients of Lens and Non-Lens Tissues Using a Multi-Tissue Eye Model to Assess Risk of Cataracts and Retinitis

“…With respect to the eye lens dosimetry measurements, Dubeau et al ( 58 ) provides a detailed description of available eye lens dosimeters that seek to measure H p (3), personal dose equivalent delivered to a 3 mm depth in an ICRU cylindrical or slab phantom. H p (3) is an operational quantity that seeks to closely approximate the dose equivalent delivered to the eye lens ( 59 ). Commercially available eye lens dosimeters were deemed to provide a satisfactory response to photon radiation, while the response to beta radiation requires improvement ( 60 ).…”

New operational quantities (RBE × D p lens/Φ) for eye lens neutron dosimetry as a function of energy and angle of incidence in the ICRU 95 formalism

“…The weighted absorbed dose data for RBE × D p lens /Φ (in pGy cm 2 ), were also compared to the equivalent operational quantity H p (3,α)/Φ (in pSv cm 2 ) conversion coefficients calculated at 3 mm depth in the ICRU cylindrical and slab phantoms for different neutron energies and angles of incidence from 0 • to 75 • in 15 • increments reported by Gualdrini et al [21] to demonstrate the relevance of this new proposed operational quantity for doses resulting in tissue reactions (deterministic effects).…”

“…In recent years, numerous studies were performed that quantified the operational quantity H p (3)/Φ for photons and beta radiation [14][15][16][17][18][19]. For neutrons, computed personal absorbed dose (D lens /Φ), and personal dose equivalent (H p (3)/Φ) were published in the relevant work completed so far [20][21][22][23]. In a recent work [24], similar computations were undertaken for different neutron energies at 0 • incidence (i.e.…”

IAEA Tec Doc-1731 ‘Implications for Occupational Radiation Protection of the New Dose Limit for the Lens of the Eye’

“…Therefore, in the absence of a cylindrical phantom, it is recommended that the slab phantom for angles of incidence up to 75° should be used because of its availability and historical use in calibration laboratories. For certain energies and angles of incidence of neutrons, whole body monitoring is not likely to be conservative with respect to dose to the lens of the eye [64]. Therefore, neutron dosimetry of the lens of the eye may become necessary in some workplace situations [64], however, this needs further investigation.…”

“…For certain energies and angles of incidence of neutrons, whole body monitoring is not likely to be conservative with respect to dose to the lens of the eye [64]. Therefore, neutron dosimetry of the lens of the eye may become necessary in some workplace situations [64], however, this needs further investigation.…”