Jan Willem Nicolaas Tuyn

The antiproton decelerator: AD

A simplified scheme for the provision of antiprotons at 100 MeV/c based on fast extraction is described. The scheme uses the existing p~ production target area and the modified Antiproton Collector Ring in their current location. The physics programme is largely based on capturing and storing antiprotons in Penning traps for the production and spectroscopy of antihydrogen. The machine modifications necessary to deliver batches of 1/spl times/10/sup 7/ p~/min at 100 MeV/c are described. Details of the machine layout and the experimental area in the existing AAC Hall are given.

The Antiproton Decelerator: AD

Abstract In view of a possible future programme of physics with low-energy antiprotons, a simplified scheme for the provision of antiprotons at 100 MeV/ c has been studied. It uses the present target area and the modified Antiproton Collector (AC) in its present location. In this report the modifications and the operation are discussed.

Status of the antiproton decelerator: AD

A simplified scheme for the provision of antiprotons at 100 MeV/c in fast extraction is described. The scheme uses the existing p production target area and the modified Antiproton Collector Ring in their current location. Some modifications necessary to deliver batches of 1 × 10 7 antiprotons every minute at 100 MeV/c are described, details of the machine layout and the experimental area in the existing AAC Hall are given.

RBE and OER values of negative pion beams from growth inhibition of Vicia Faba roots

SummaryTwo pion beams of different momentum width have been used to expose meristems of Vicia Faba roots under aerobic and hypoxic conditions. The measurements of the resulting 10 days growth inhibition after exposures at various locations on the pion beam axes have been made and RBE and OER values evaluated for 50% effects compared to60Co tiγ-rays. The results have been related to the fractional doses from star products defined by telescope measure ments of stopped pions along the same beams. It has been found that the RBE value increases with the fractional “star dose” up to a maximum after which the RBE decreases. The OER values, however, were found to decrease with increas ing “star dose” fraction rather rapidly after which it was found to be independent of the “star dose” contribution.

A PERSONAL NEUTRON MONITORING SYSTEM BASED ON SOLID STATE NUCLEAR TRACK DETECTORS

ABSTRACT The use of solid state nuclear track detectors for personal neutron monitoring around high energy particle accelerators has been extensively investigated at CERN. A system based on cellulose nitrate (LR115) as a track detector in contact with different radiators (boron and polycarbonate) has been proposed to replace the NTA neutron film used so far. The holes created in the cellulose nitrate layer by charged particles such as alpha particles and carbon recoils are counted after etching with a microscope connected to an image-analysing computer (Quantimet). The present paper describes the monitoring system chosen and presents the results of a large series of tests (calibration and field experiments) at CERN. The problems encountered in going from laboratory-scale tests to a large-scale routine use of the neutron monitoring system are discussed. The use of 6LiF/7LiF thermoluminescence detectors in conjunction with the track detector system to select the track detectors that require evaluation is proposed.