The relative biological effectiveness (RBE) is an important parameter in heavy ion treatment planning. It is well known that the RBE does not only depend on the LET of a particle, but also on the ion sort.. This can be explained by the difference in the local ionisation distribution for different kind of ions, expressed by LET and radial ionisation distribution. Our goal is to measure these par...

The use of pure heavy hydrocarbons like propane or isobutane has some advantages for drift chaders that measure the specific ionisation for particle identification. With a prototype of the ARGUS drift chamber various gases were tested with a 3 GeV/c electron beam. We found a dE/dx resolution for propane of Fwhm= 10.4% and for isobutane Fwhm = 9.9X, by a factor of + 1.6 better than that for argo...

A primary standard for positron-emitters in gas has been developed. The method involves internal gas proportional counting and the use of the PENELOPE Monte Carlo code to determine corrections for counting losses. The development work was carried out using (11)C, although the method can be applied to other positron emitters. The results were compared with measurements of (11)C (in solution) car...

As the pre-calibrated sample containers used for activity assay in the two NPL secondary standards ionisation chambers are being phased out, suitable replacements have been identified. Characterisation checks have been carried out on the new ISO ampoules and a long-term recalibration schedule has been devised. Around 40 calibration factors have been determined so far and comparison of ion chamb...