Production of Highly Polarized Positrons Using Polarized Electrons at MeV Energies.

The Polarized Electrons for Polarized Positrons experiment at the injector of the Continuous Electron Beam Accelerator Facility has demonstrated for the first time the efficient transfer of polarization from electrons to positrons produced by the polarized bremsstrahlung radiation induced by a polarized electron beam in a high-Z target. Positron polarization up to 82% have been measured for an initial electron beam momentum of 8.19 MeV/c, limited only by the electron beam polarization. This technique extends polarized positron capabilities from GeV to MeV electron beams, and opens access to polarized positron beam physics to a wide community.

Development of a µ-TPC detector as a standard instrument for low-energy neutron field characterisation.

In order to measure the energy and fluence of neutron fields, in the energy range of 8 to 1 MeV, a new primary standard is being developed at the Institute for Radioprotection and Nuclear Safety (IRSN). This project, Micro Time Projection Chamber (µ-TPC), carried out in collaboration with the Laboratoire de Physqique Subatomique et de Cosmologie (LPSC), is based on the nucleus recoil detector principle. The measurement strategy requires track reconstruction of recoiling nuclei down to a few kiloelectronvolts, which can be achieved using a micro-pattern gaseous detector. A gas mixture, mainly isobutane, is used as an n-p converter to detect neutrons within the detection volume. Then electrons, coming from the ionisation of the gas by the proton recoil, are collected by the pixelised anode (2D projection). A self-triggered electronics system is able to perform the anode readout at a 50-MHz frequency in order to give the third dimension of the track. Then, the scattering angle is deduced from this track using algorithms. The charge collection leads to the proton energy, taking into account the ionisation quenching factor. This article emphasises the neutron energy measurements of a monoenergetic neutron field produced at 127 keV. The fluence measurement is not shown in this article. The measurements are compared with Monte Carlo simulations using realistic neutron fields and simulations of the detector response. The discrepancy between experiments and simulations is 5 keV mainly due to the calibration uncertainties of 10 %.

A comparison of electrosurgery and sharp debridement in the treatment of chronic neurovascular, neurofibrous and hard corns. A pragmatic randomised controlled trial.

A randomised controlled trial was undertaken to compare treatment outcomes for neurovascular, neurofibrous and hard corns. Patients with suitable lesions were referred from community clinics within Manchester PCT. Fifty-nine subjects were enrolled into the study and randomised to one of two treatment groups; group (a) those treated with electrosurgery and (b) a control group treated with standard sharp debridement. The principle outcome measure was the Visual Analogue Scale (VAS) pain score (0, no pain; 10, worst pain experienced) and lesions were categorised as demonstrating no change, partial or complete resolution. Data were analysed using 'Intention to Treat' methodology, i.e. analysis of data from subjects randomised to each group (electrosurgery group n=34; control group n=25). The results show a statistically significant reduction in pain in group (a) as reported at the 6 month review (p=0.0001) with a complete and partial resolution rate of 26% and 50%, respectively compared with group (b) whose pain level reduction was not significant and which showed resolution rates of 4% and 28% only.