IR characterization of graphite black-coating for cryogenic detectors

• Published in: Infrared physics & technology Vol. 50; no. 1; pp. 58 - 62
• Main Authors: Mellouki, I., Bennaji, N., Yacoubi, N.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.03.2007; Elsevier
• Subjects: Bolometer; infrared, submillimeter wave, microwave and radiowave receivers and detectors; Cryogenic thermal sensors; Exact sciences and technology; Fundamental areas of phenomenology (including applications); Graphite-black; Infrared, submillimeter wave, microwave and radiowave instruments, equipment and techniques; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; IR coatings; Optical coatings; Optical elements, devices, and systems; Optics; Physics; Reflectance; Cryogenic thermal sensors; IR coatings; Graphite-black; Reflectance; Infrared detectors; Sensitivity analysis; Radiation detectors; Cryogenic temperature; Reflectivity; Graphite; Infrared radiation; Optical coatings; Paints; Normal incidence
• ISSN: 1350-4495; 1879-0275
• DOI: 10.1016/j.infrared.2006.05.002

We are developing an infrared thermal sensor to meet the growing needs of such detectors, operating at room and cryogenic temperature. For these facilities, two types of optical absorbing coatings were investigated. First was graphite-black coating and second was matt black paint, both are deposed on substrates simply by spray. IR spectroscopy measurements made on graphite layer revealed that reflectance at normal incidence varies by less than 10% at 10 μm and at 20 μm. Hence, thermal sensors using this coating had high and flat spectral sensitivity from 2.5 μm to 20 μm. These results are compared to measurements made on matt black paint and gold-black coatings documented in bibliography. Electrical characterization at room and cryogenic temperature indicated that graphite-black had a temperature coefficient of 5.510 −3 K −1 at 300 K and −5.110 −3 K −1 at 80 K, while matt black paints was electrically insulator.