Objective
Biological target size of radiation action is known to have nanometric dimensions (2 nm for the DNA,# 10 nm for the nucleosomes, 30 nm for the basic fibre. 300 nm for threaded fibre). Models of the radiation action variously interpret the early damage in terms of primary ionisation spacing; others in terms of ionisation clusters, with yield of nth order (with n = 3, 4 or more) in a given nanometric volume; others in terms of specific energy absorbed in nanometric volumes, others of reduced LET, and so on. To update the assessment of radiation risk to accommodate the advances both in the radiobiology and in biophysical modelling of the radiation action, it is therefore necessary to devise detectors, for external radiation monitoring, which are based on physical quantities measured at the nanometre level The project aims to investigate the possibility of creating a new generation of active exposure monitors able to assess the radiation quality on the bases of physical measurements carried out at the nanometre level.
Since these monitors will measure radiation features which are closely related to the initial lesions of the radiation, they should be suitable to monitor also the quality in less common but complex radiation fields like those experienced in spacecraft, in high altitude flights and around high energy particle accelerators.
Moreover, active monitors with nanometric sensitive volumes will have a positive impact in the risk assessment of short-range radiations (e.g. incorporated Auger emitters and intermediate energy neutrons). In order to take advantage of the density scaling factor, the nanometric monitors will be tissueequivalent gas detectors. Therefore the project proposes to investigate the gas detector physics and technology to manufacture detector prototypes able to perform properly nanometric measurements. Moreover, the project proposes to collect new basic physics data regarding the interaction of the radiation with organic gases, in order to properly evaluate the response functions of the future nanometric monitors and the physical meaning of the measured quantities. The project is divided in 4 working packages:
WPl: development of detectors for track-nanodosimetry.
WP2: basic physical data in organic gases.
WP3: nanometric gas counters for quality measurements in operational fields.
WP4: implementation of a general code for modelling cylindrical TEPC's. Four partners will collaborate at these 4 WPs: LNL (Legnaro-Italy), PTB (Braunschweig-Germany), USTAN (St.Andrews-Scotland) ADPA (Toulouse-France). The project involves even the specialist expertise of two sub-contractors: the Weizmann Institute in Israel and the Soltan Institute for Nuclear Studies in Poland.
WPl aims to develop, by following two different approaches, a counter able to measure the ionisation spectrum in nanometric volumes placed at a variable distance from the particle trajectory.
WP2 aims to update the electron-molecule cross-section knowledge in organic gases; to measure electron W-values of DME (a very promising gas for nanometric counters); to implement an electron trackstructure code for tissue-equivalent gas mixtures; to measure ionisation spectra around charged particle tracks with nanometric resolution.
WP3 aims to develop nanometric counters which should be capable of measuring the primary ionisation mean free path (landa) and altematively the dose distributions of the restricted-LET (L100,D).
WP4 aims to implement a code to describe the electron transport and the electron-avalanche growing in any cylindrical counter. This provides a tool for designing TEPCs which will be able to simulate volumes of any diameter down to nanometric dimensions.
Calculations and experimental data intercomparisons, measurements in calibrated and realistic operational radiation fields will ensure a proper evaluation of project results.
Programme(s)
Call for proposal
Data not availableFunding Scheme
CSC - Cost-sharing contractsCoordinator
35020 LEGNARO
Italy