Abstract: Provided is a radiation detector with improved n/? discrimination and usable even under high counting rate conditions with a reduced load on a signal-processing system. The detector capable of distinguishing neutron and gamma-ray events includes: a scintillator; an optical filter; a first photodetector to which a first part of light emitted from the scintillator is introduced via the optical filter; and a second photodetector to which a second part of light emitted from the scintillator is introduced not via the optical filter, wherein, for a set of two wavelengths A and (A+B) nm, the scintillator emits at least a light of A nm and a light of (A+B) nm when irradiated by gamma-ray, and emits a light of A nm and does not emit a light of (A+B) nm when irradiated by neutrons; and the optical filter blocks the light of A nm and transmits the light of (A+B) nm.

Abstract: Provided is a scintillation neutron detector capable of measuring neutrons with precision even under a high amount of ? rays as background noise and excellent in neutron counting precision, the scintillation neutron detector comprising a neutron scintillator crystal containing 6Li, and the crystal having a specific surface area of no less than 60 cm2/cm3.

Abstract: A crusher which can transmit energy to be applied to a piston to a silicon lump efficiently, and a silicon lump crushing apparatus which can crush a silicon lump into small pieces by suppressing the production of powders as much as possible and enables the automation of the crushing work of a silicon lump. The crusher is constituted such that a hammer head is connected to a piston. When compressed air is not applied to the piston, the hammer head is elastically urged to a standby position and when compressed air is applied to the piston, the hammer head is moved from the standby position to collide with the silicon lump. In the silicon lump crushing apparatus, a plurality of crushers having a hammer head to be collided with a silicon lump are opposed to the silicon lump supported on a support base and spaced apart from one another.