Variation in optical constants between photocathodes

Harmer, S W, Downey, R, Wang, Y and Townsend, P D (2006) Variation in optical constants between photocathodes. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 564 (1). pp. 439-450. ISSN 0168-9002

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The complex permittivity values of four S20 photocathodes are reported and contrasted. Values were obtained indirectly by measuring the reflectance of the cathode and then using non-linear fitting software to obtain the best estimates of the real and imaginary parts of the complex permittivity, together with the thickness of the cathode layer. The permittivity values span the wavelength range from 250 to 950 nm. The values are broadly similar for the 4 sets of data. However, the variations may reflect the fact that the S20 is believed to consist of alkali compounds with at least two different stoichiometric compositions and the stoichiometry may not be identical between cathodes. For comparison purposes data were recorded for a simpler composition bi-alkali cathode and compared with earlier data derived from an alternative analysis and there was good agreement between the values from the two methods.

Item Type: Article
Schools and Departments: School of Engineering and Informatics > Informatics
Depositing User: Peter Townsend
Date Deposited: 06 Feb 2012 18:26
Last Modified: 11 Jun 2019 10:58
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