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Silicon emissivity as a function of temperature

Constancio, Marcio, Jr. and Adhikari, Rana X. and Aguiar, Odylio D. and Arai, Koji and Markowitz, Aaron and Okada, Marcos A. and Wipf, Chris C. (2020) Silicon emissivity as a function of temperature. International Journal of Heat and Mass Transfer, 157 . Art. No. 119863. ISSN 0017-9310. doi:10.1016/j.ijheatmasstransfer.2020.119863.

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In this paper we present the temperature-dependent emissivity of a silicon sample, estimated from its cool-down curve in a constant low temperature environment ( ~ 82K). The emissivity value follow a linear dependency in the 120–260 K temperature range. This result is of great interest to the LIGO Voyager gravitational wave interferometer project since it would mean that no extra high thermal emissivity coating on the test masses would be required in order to cool them down to 123 K. The results presented here indicate that bulk silicon itself can have sufficient thermal emissivity in order to cool the 200 kg LIGO Voyager test masses only by radiation in a reasonable short amount of time (less than a week). However, it is still not clear if the natural emissivity of silicon will be sufficient to maintain the LIGO Voyager test masses at the desired temperature (123 K) while removing power absorbed by the test masses. With the present results, a black coating on the barrel surface of the test masses would be necessary if power in excess of 6 W is delivered. However, the agreement we found between the hemispherical emissivity obtained by a theory of semi-transparent Silicon and the obtained experimental results makes us believe that the LIGO Voyager test masses, because of their dimensions, will have effective emissivities around 0.7, which would be enough to remove about 8.6 W (7.5 W) for a shield at 60 K (80 K). This hypothesis may be confirmed in the near future with new measurements.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Adhikari, Rana X.0000-0002-5731-5076
Arai, Koji0000-0001-8916-8915
Additional Information:© 2020 Elsevier Ltd. Received 26 November 2019, Revised 7 April 2020, Accepted 24 April 2020, Available online 27 May 2020. MC and ODA thank CNPq for financial support (grants #300240/2019-8 and #302841/2017-2). Also, they thank to Manel Molina Ruiz for the useful discussion about fitting and to Martin Fejer for suggesting a way to compare the experimental results to theoretical expectations.
Funding AgencyGrant Number
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)300240/2019-8
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)302841/2017-2
Subject Keywords:LIGO; Silicon; Thermal emissivity; Gravitational waves
Record Number:CaltechAUTHORS:20200527-134350622
Persistent URL:
Official Citation:Marcio Constancio Jr, Rana X. Adhikari, Odylio D. Aguiar, Koji Arai, Aaron Markowitz, Marcos A. Okada, Chris C. Wipf, Silicon emissivity as a function of temperature, International Journal of Heat and Mass Transfer, Volume 157, 2020, 119863, ISSN 0017-9310, (
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:103498
Deposited By: Tony Diaz
Deposited On:27 May 2020 21:04
Last Modified:16 Nov 2021 18:22

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