公开(公告)号：JPS63318060A

公开(公告)日：1988-12-26

申请号：JP15254187

申请日：1987-06-19

Applicant: ALOKA CO LTD

Inventor： KOYANO AKIRA ,  OSHIMA TOSHINORI ,  SATO HIROO ,  MAEKAWA HIROSHI ,  YANAI TOSHIO ,  YOSHIZUMI MINORU ,  SATOU SEIGO

IPC: H01J47/08 ,  G01T1/18

Abstract: PURPOSE:To effectively prevent the incidence of ultraviolet rays or the like and correctly measure radioactive rays by forming a radioactive ray incidence window with titanium foil. CONSTITUTION:A radioactive ray incidence window 20 is formed with a layer of titanium foil, the radioactive ray incidence window 20 has the thickness of about 6-7mu, and its periphery is welded to a cathode cylinder 12. Since the titanium foil has sufficient strength regardless of its thickness of 6-7mu a counter tube 10 is not broken even if its interior is in a decompressed state. It abounds in the light shielding property and can reliably prevent the incidence of ultraviolet rays or the like. The miscount due to the photoelectric effect is thereby prevented, and radioactive rays can be correctly detected.