Total Reflection Type Research Articles

A Total Reflection Type Čerenkov Counter with High Efficiency

A threshold-type Čerenkov counter which makes use of total reflection in a Lucite radiator, is constructed and tested using pion beams with various velocities. The detection efficiency of about 100% for relativistic particles (β≈1) is obtained. The detection threshold is found to be β≈0.9, whose value is expected from the calculation assuming the index of refraction of Lucite to be 1.49. The counter is successfully used to separate K± mesons from pions in the momentum range below 700 MeV.

On a Sodium Nitrate Polarization Prism and a Polarization Plate of Scattering Type

Two types of polarizers are constructed, one being the “total reflection type” similar to the Feussner prism and the other is the “scattering type”, in which the principle of Christiansen filter holding for the polarization. The former is made of a thin single crystal of sodium nitrate grown between two prisms of SK5 glass or two glass plates which are cemented to two prisms of the same kind of glass by Canada balsam. No use of organic binders to attach the crystal to the glass remarkably simplifies the manufacturing process as well as protection of the polarizers from deteriorations due to the deliquenscence of the crystal. The polarizer of the “scattering type” is constructed by binding directly two roughly ground surfaces of SK5 glass plates with a thin single crystal of sodium nitrate. As SK5 glass has the same refractive index with that of ordinary ray in sodium nitrate, and the orientation of the optical axis of the crystal is so chosen that it lies in the plane of the glass plate, the extraordinary...