PS174 precision survey of X-rays from -pp (-pd) atoms using the initital LEAR beam problems and their solutions

This chapter discusses an experiment which utilizes a gas target developed from that used to find K-p X-rays in order to search for the K and L X-rays from -pp (-pd) atoms. Topics covered include the use of SiLi detectors; X-ray windows and background lines; stark mixing and rates; and the state of preparation. It is shown how the PS174 apparatus matches the experimental objectives and overcomes the technical problems. The objectives of the experiment are to search for K X-rays from -pp and -pd atoms and then to measure their shift and width relative to quantum electrodynamic (QED) predictions; to measure the intensity of X-rays feeding to and from the 2p state to derive the p-wave annihilation probability; to investigate the intensity of both series as functions of density as the first detailed check of the various cascade calculations in hydrogen; and to obtain -p He spectra over the same density range as further checks on cascade calculations, particularly the intensity anomaly between liquid and gas