Proof of principle of a high-spatial-resolution, resonant-response gamma-ray detector for Gamma Resonance Absorption in 14N

The development of a mm-spatial-resolution, resonant-response detector based on a micrometric glass capillary array filled with liquid scintillator is described. This detector was developed for Gamma Resonance Absorption (GRA) in 14N. GRA is an automatic-decision radiographic screening technique that combines high radiation penetration (the probe is a 9.17 MeV gamma ray) with very good sensitivity and specificity to nitrogenous explosives. Detailed simulation of the detector response to electrons and protons generated by the 9.17 MeV gamma-rays was followed by a proof-of-principle experiment, using a mixed gamma-ray and neutron source. Towards this, a prototype capillary detector was assembled, including the associated filling and readout systems. Simulations and experimental results indeed show that proton tracks are distinguishable from electron tracks at relevant energies, on the basis of a criterion that combines track length and light intensity per unit length.Comment: 18 pages, 16 figure

Parity Violation in Proton-Proton Scattering

Measurements of parity-violating longitudinal analyzing powers (normalized asymmetries) in polarized proton-proton scattering provide a unique window on the interplay between the weak and strong interactions between and within hadrons. Several new proton-proton parity violation experiments are presently either being performed or are being prepared for execution in the near future: at TRIUMF at 221 MeV and 450 MeV and at COSY (Kernforschungsanlage Juelich) at 230 MeV and near 1.3 GeV. These experiments are intended to provide stringent constraints on the set of six effective weak meson-nucleon coupling constants, which characterize the weak interaction between hadrons in the energy domain where meson exchange models provide an appropriate description. The 221 MeV is unique in that it selects a single transition amplitude (3P2-1D2) and consequently constrains the weak meson-nucleon coupling constant h_rho{pp}. The TRIUMF 221 MeV proton-proton parity violation experiment is described in some detail. A preliminary result for the longitudinal analyzing power is Az = (1.1 +/-0.4 +/-0.4) x 10^-7. Further proton-proton parity violation experiments are commented on. The anomaly at 6 GeV/c requires that a new multi-GeV proton-proton parity violation experiment be performed.Comment: 13 Pages LaTeX, 5 PostScript figures, uses espcrc1.sty. Invited talk at QULEN97, International Conference on Quark Lepton Nuclear Physics -- Nonperturbative QCD Hadron Physics & Electroweak Nuclear Processes --, Osaka, Japan May 20--23, 199

WORKSHOP REPORT ON POLARIZED PROTON ION SOURCES

Nous présentons ici le résumé d'un atelier qui a examiné les performances actuelles et les possibilités futures des sources de protons polarisés en mai 1983. Les meilleures sources basées sur l'effet Lamb ont atteint 4 μA mais les perspectives d'accroissement sont limitées par la luminosité de la source. Les sources atomiques ont atteint environ un niveau de 8 μA en [MATH]- et on a proposé des techniques pour accroitre leur niveau jusqu'à 1 mA. On décrit des techniques pour réaliser des faisceaux pulsés intenses à partir de sources atomiques ultra-froides. On présente les résultats obtenus avec une source d'ions H- à pompage optique ainsi que d'autres méthodes pour produit de l'hydrogène atomique polarisé par pompage optique.The results from a workshop, during May 1983, which examined the capabilities and future possibilities of polarized proton sources are summarized. The best Lamb-shift sources have achieved 4 μA but the potential for further increase is limited by the proton source brightness. Atomic sources have reached the ~ 8 μA [MATH]- range and techniques for increasing this to ~ 1 mA are proposed. Techniques for achieving intense pulsed beams with ultra cold atomic sources are described. Results from an optically pumped [MATH]- ion source at KEK are given along with alternative schemes for producing polarized atomic hydrogen by optical pumping