The Bristol HIDAC 2D-ACAR Spectrometer

16th International Conference on Positron Annihilation

Dugdale, S.B.^1 ; Laverock, J.^1 ; Utfeld, C.^1 ; Alam, M.A.^1 ; Haynes, T.D.^1 ; Billington, D.^1 ; Ernsting, D.^1

H.H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL, United Kingdom^1

关键词: Anger camera;    Measurements of;    Momentum distributions;    Position resolution;    Position-Sensitive Detectors;    Surface study;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/443/1/012083/pdf
DOI  :  10.1088/1742-6596/443/1/012083

来源: IOP

【 摘 要 】

We describe the Bristol spectrometer for positron annihilation Fermi surface studies utilising high-density avalanche chambers (HIDACs) as position sensitive detectors. Measurements on α-SiO2show, through the momentum distribution of para-positronium, the substantial improvement in resolution compared to Anger cameras. Measurements of the Fermi surface of V are used to determine the resolution. The new spectrometer is found to have an efficiency of 12.5 ± 0.6 % and a (coincidence) contribution to the position resolution of 0.96 ± 0.1 mm.