Technical note Neutron and gamma ray heating in the grazing incident liquid metal mirrors for laser inertial fusion energy power plants Su¨ mer S¸ ahin a, *, Abdulmuttalip S¸ahinaslan b a GaziU ¨ niversitesi,TeknikEg ˘itimFaku ¨ tesi,Besevler,06500Ankara,Turkey b I . no ¨nu ¨U ¨ niversitesi,Mu ¨hendislikFaku ¨ltesi,Malatya,Turkey Received 3 April 2001; accepted 9 May 2001 Abstract A thin film of liquid metal can serve as final optics of a laser inertial fusion energy (IFE) power plant. Calculations of pulsed neutron and gamma-ray heating are presented for a grazing incident liquid metal mirror (GILMM) used for robust final optics of a laser IFE power plant. Different liquid films (Li, Na, Mg, Al, Si, K, Ga, Ag, Au, Pb, Bi and Flibe ‘‘Li 2 BeF 4 ’’) are considered at a distance of 30 m from a nominal 1 GJ fusion source as well as different substrate materials (SS-304 and SiC). The effect of neutron heating both in the liquid metal film as well as in the subsrate material will be by around three to four orders of magnitude lower than the laser heating limit. Hence the nuclear heating will not be a limiting factor for grazing incident liquid metal mirror (GILMM) of a laser IFE power plant. # 2002 Elsevier Science Ltd. All rights reserved. 1. Introduction Metal mirrors have long been used in optics. The amount of incident energy the mirror can withstand, called the damage limit, is set by surface deformation which is dependent on surface temperature rise. In laser optics, the energy deposition density on the mirror can be reduced significantly by grazing incidence (  85  to normal). This allows an important increase of the light intensity by the same damage limit of the mirror. An early analysis of a grazing incident metal mirror (GIMM) can be Annals of Nuclear Energy 29 (2002) 631–638 www.elsevier.com/locate/anucene 0306-4549/02/$ - see front matter # 2002 Elsevier Science Ltd. All rights reserved. PII: S0306-4549(01)00059-7 * Corresponding author. Tel.: +11-90-312-2124304; fax: +11-90-312-2120059. E-mailaddresses: sumer@gazi.edu.tr (S. S¸ahin), atalip@inonu.edu.tr (A. S¸ahinaslan).