Method for measuring absorptivity and sensitivity of same multi-alkali photocathode

Abstract

The invention discloses a method for measuring absorptivity and sensitivity of the same polyalkali photocathode, which comprises the following steps of: 1) preparing two image tubes by the same process, arranging no micro-channel plate in each tube, plating a chromium electrode in a half area of the inner surface of an anode output window, preparing a layer of polyalkali photocathode on the inner surface of anti-halation glass of one image tube to serve as a test tube, not preparing a photocathode on the inner surface of the anti-halation glass of the other image tube, so that the other image tube is used as a control tube; 2) installing the image tube on a reflectivity tester for testing to obtain reflectivity R1 and R2 of the tested and control tube; 3) installing the image tube on a transmittance tester for testing to obtain the transmittance T1 and the transmittance T2 of the test tube and the control tube; 4) calculating the absorptivity A = (R2 + T2)-(R1 + T1); and 5) installing the test tube on a sensitivity tester, recording the input luminous flux phi, and measuring the cathode current I bright and I dark, so that the sensitivity S is equal to 2 * (I bright-I dark) / phi. The method is simple to operate and high in precision.

Description

technical field

[0001] The invention belongs to the field of low-light image intensifier tubes, in particular to a method for measuring the absorptivity and sensitivity of the same multi-alkali photocathode.

[0002] technical background

[0003] The low-light image intensifier tube is the core device of the low-light night vision device, and it is widely used in the fields of target observation, detection, search and rescue under various nighttime environmental conditions.

[0004] At present, the mainstream low-light night vision core device in China is still a low-light image intensifier tube with a multi-alkali photocathode as the photoelectric conversion material. shell composition. Its working principle is that the external incident light irradiates the cathode input window of the image intensifier and is absorbed by the photocathode. The photocathode is excited to radiate photoelectrons outward. Under the action of an external electric field, the photoelectrons move d...

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