Radon emanation coefficient study of a geological sample

The radon atom can escape from the material it was formed in by direct recoil or by diffusion. It then enters either an inter or intra-granular space. Next, the radon atom can migrate by diffusion or convection in order to reach the atmosphere. The emanation coefficient is defined as the ratio between the number of radon atoms that escape from the matrix and the total number produced in the entire material. We propose to define a protocol in order to measure this emanation coefficient by a differential gammametric method. This method consists in determining the concentration of the short, half-life progenies of radon (essentially lead-214 and bismuth-214) through measuring their gamma-ray intensities in a hermetic cell before and after radioactive equilibrium. The first gamma measurement results give us the quantity of radon trapped in the solid matrix. A second analysis, after 13 days, gives the total production of the progenies, and thus the total radon in the sample. The measurements of a sample that is both dried and saturated are necessary to estimate the radon emanation potential. The influence of the fluid in the porous space is discussed in a theoretical way. This approach is applied to a geological sample and compared with the experimental results

Ion-Kill Dosimetry

Unanticipated late effects in neutron and heavy ion therapy, not attributable to overdose, imply a qualitative difference between low and high LET therapy. We identify that difference as ‘ion kill’, associated with the spectrum of z/β in the radiation field, whose measurement we label ‘ion-kill dosimetry’

Chemical Bonds Broken in Latent Tracks of Light Ions in Plastic Track Detectors

When a swift ion is slowed down through a plastic detector it creates a latent track. In nuclear track detectors, this latent track can be specifically etched by an appropriate chemical solution. This enlargement process is due to a higher etch velocity (VT) along the ion\u27s path than in the non-damaged part of the detector. The etched track velocity is definitely linked to the damage created by the incoming ion in the detector material. A relationship between the physical parameters of the energy deposition and the variation in this etched track velocity with the ion energy cannot easily be explained. We present here our study on the chemical damage created by several ions in a cellulose nitrate type detector and our first attempt to simulate them by the use of the hit theory