International Conference on Occupational Radiation Protection: Strengthening Radiation Protection of Workers – Twenty Years of Progress and the Way Forward

Implications of the ICRU 95 quantities for Swiss personal dosimetry services: a status quo

Not scheduled

1h 30m

Geneva

Poster 1. Review of international standards and recommendations on occupational radiation protection, progress over the past twenty years and existing challenges Session 1. Review of standards and recommendations on occupational radiation protection at the international, regional, and national levels: Progress over the past twenty years and existing challenges

Speaker

Lily Bossin (Paul Scherrer Institute)

Description

The main objective of the revision of operational quantities for personal dosimetry as introduced in the ICRU Report 95 was to use more realistic human phantoms in the calculations of conversion factors between quantities, and hence to allow for more appropriate personal dose estimates, H$_{\text{p}}$, and skin dose estimates, D$_{\text{local skin}}$. The simplified geometries used in the past had led to over- or underestimates of the operational quantities H$_{\text{p}}$(10) and H$_{\text{p}}$(0.07) defined by the ICRU Report 51, in the low and high photon energy ranges (< 50 keV and > 3 MeV respectively). In practice, this means that dosimeters optimised for the ICRU Report 51’s quantities will exhibit an over-response at photon energies <50 keV (predominantly used in medical applications) in terms of the ICRU Report 95’s quantities, if no change in design or evaluation algorithm is adopted.

The objective of this work is to assess the photon response of the dosimetry systems used across Switzerland in terms of the operational quantities for external radiation exposure personal dose, H$_{\text{p}}$, and personal absorbed dose in local skin, D$_{\text{local skin}}$, defined in the ICRU Report 95. The responses of the dosimetry systems (angle and energy response) in terms of the new ICRU Report 95 quantities are calculated by combining their measured responses in terms of the ICRU Report 51 quantities and the conversion coefficients from air kerma to H$_{\text{p}}$ and D$_{\text{local skin}}$, as done by Otto (2019), Hoeldmoser et al. (2020) and Bossin et al. (2022).

The dosimetry systems investigated include thermoluminescence (TL) systems based on LiF:Mg,Ti, Li$_2$B$_4$O$_7$:Mn,Si, Li$_2$B$_4$O$_7$:Cu and CaSO$_4$:Tm, a BeO-based optically stimulated luminescence (OSL) system, a radiophotoluminescence (RPL) system based on Ag+-doped phosphate glass, and a direct-ion-storage (DIS) system. Therefore, the results are representative of the situation that many individual dosimetry services are facing following the changes introduced by the ICRU Report 95, and helps to evaluate the challenges ahead.

References

Bossin, L., Christensen, J., Pakari, O., Yukihara, E. (2022). Performance of radiophotoluminescence personal dosimeters in terms of the ICRU Report 95's operational quantities. Submitted for publication.

Hoedlmoser, H., Bandalo, V., & Figel, M. (2020). BeOSL dosemeters and new ICRU operational quantities: Response of existing dosemeters and modification options. Radiation Measurements, 139, 106482.

Otto, T. (2019). Response of photon dosimeters and survey instruments to new operational quantities proposed by ICRU RC26. Journal of Instrumentation, 14(01), P01010.

Presentation materials

Poster_IAEA_v2.pdf