Ultrahigh-Sensitivity Pickup Tube Using 35-µm-Thick HARP Photoconductive Film

Yuji OHKAWA  Kazunori MIYAKAWA  Tomoki MATSUBARA  Kenji KIKUCHI  Shirou SUZUKI  Misao KUBOTA  Norifumi EGAMI  Akira KOBAYASHI 

Publication
IEICE TRANSACTIONS on Electronics  Vol.E92-C  No.6  pp.894-897
Publication Date: 2009/06/01
Online ISSN: 1745-1353
Print ISSN: 0916-8516
Type of Manuscript: LETTER
Category: Semiconductor Materials and Devices
Keyword: 
HARP,  photoconductive film,  avalanche multiplication,  amorphous,  selenium,  high sensitivity, 

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Summary: 
A high-sensitivity pickup tube using HARP (high-gain avalanche rushing amorphous photoconductor) photoconductive film, which makes use of the avalanche multiplication phenomenon, has been studied for making a high-sensitivity television camera. The avalanche multiplication factor, i.e., sensitivity, was increased by thickening the film. A 35-µm-thick HARP film, which was more sensitive than the previous 25-µm-thick film with an avalanche multiplication factor of about 600, and a 2/3rd-inch pickup tube using the film were developed. Measurements on the pickup tube demonstrated that it had an avalanche multiplication factor of about 1000, low lag, and high resolution. Moreover, image defects caused by shooting of intense spot lights were investigated, and it was found that exposing the film to UV light before operation and controlling the temperature of the film during operation could suppress the defects.