Studies on the wave property of neutron and its application to the measurements of space-time symmetries

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(1) Origin of large enhancement of the parity violation effect in neutron reactions has been investigated. First, the longitudinal asymmetries is nuclear absorptions of neutrons in p-wave resonances has been measured for several medium and heavy nuclei at LANSCE in the energy of several hundred eV to 2 KeV. We have analyzed the data to calculate the dispersion of weak matrix of the reactions and have deduced the average weak spreading width (I'w) to be (0.5^^+__-0.3) × 10^<-7> eV. We have measured also the parity non-conserving spin rotation of neutrons in the 0.734-eV p-wave resonance of ^<139>La. The rotation angle was determined to be (7.4^^+__-1.1) × 10^<-3>rad./cm. The results agree well with the prediction of the s-p mixing model.(2) The measurements of the survival time of ultra-cold neutrons in solid deuterium have been made for the first time. This critical parameter provides fundamental limitation to the effectiveness of super-thermal UCN sources that utilize solid ortho-deuterium as the source material.(3) Self regulation of the cold neutron source with a cylindrical annulus moderator cell has been investigated. The simulation shows us that the buffer tank pressure and the liquid level in the moderator cell are stable even against large disturbance of the total heat load.(4) We have observed decoherent phenomena in spin interference in between two neutron spin states inserting several different Ni_<25> Ti_<75> power samples. The samples have been made by Mechanical Alloying Method with different milling time. We have found an improvement of the visibility by increasing their alloying time.