Pergnmon zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA J Qum Spec~ r osc Radr or Tr omler Vol 51 No I ? pp 349-355 1994 Elsevw Smnce Ltd Primed in Great Brcm 00224073(93)EOIM-T MI??-4073 94 $6 00 + 0 00 zyxwvutsrqpo A BSORPTION SPECTROSCOPY OF RADIATIVELY-HEATED LOW-Z FOILS J F SEELY,t U FELDMAN.tC M BROWN,7 B A HAMMEL.~ C A BACK,$E HSIEH,~ and R W LEES tE 0 Hulburt Center for Space Research Naval Research Laboratory 4555 Overlook Avenue S W Washmgton. DC 20375-5352 and SLawrenee LIbermore NatIonal Laboratory Llbermore CA 94550 USA Abstract-Hugh-resolution absorption spectra of radlatlvely-heated low-Z foils (CH and BN) have been recorded at the Nova II laser faclhty by a grazmg-mcldence spectrograph Using a cahbrauon curve for Kodak 101 photographtc plates, the plate density was comerted to relative intensity transmitted by the foil Absorption spectra are presented for the elements B, C, and N The absorption features near the nickel L edge In the wavelength region I I-15 A are also presented INTRODUCTION The absorption spectra of radlatlvely-heated CH and BN fads have been studied at the Nova II laser faclhty usmg a high-resolution grazmg-Incidence spectrograph The foils were indirectly heated and backht by the x-ray contmua from nearby gold fads The expenmental details and prehmmary spectra were discussed m Ref I In this paper we present a cahbratlon of the Kodak IO1 photographlc plates that were used to record the spectra, the derivation of the relative mtensltles transmltted by the foils. and the absorption spectra of CH and BN foils PLATE CALIBRATION The spectra were recorded by a 3 m grazing-mcldence spectrograph that was described m Ref 2 The radiation from the target was focused onto the entrance slit of the spectrograph by a cyhndrlcal gold-coated mirror The radlatlon was incident on the mirror at a grazing angle of 2 The linear Image formed by the mirror was shghtly tilted with respect to the entrance slit. and this resulted m the spatial resolutron of the spectrum m one dlmenslon The radiation was then Incident on a gold-coated gratmg at a grazmg angle of 2’ The gratmg had I200 grooves/mm and a blaze angle of 2-35’ The spectra were recorded on Kodak IO1 plates that were bent to conform to the Rowland circle The plate cahbratlon was determmed by recordmg the spectra transmltted through a step wedge filter The filter covered half of the entrance slit so that unfiltered and filtered spectra were simultaneously recorded on the same laser shot The step wedge filter was composed of I, 2, 4. 6, and 8 thicknesses of parylene-D foil, where the thickness of a single foil was 1300 A The mtenslty of the radiation reachmg the emulsion was the product of the intensity emltted by the plasma, the reflectance of the gold-coated mirror, the transmittance of the filter, the efficiency of the gold-coated gratmg, and the transmittance of the thm emulsion gelatm Each of these quantities was dependent on the wavelength of the radlatlon The target was a gold disk Irradiated at low Intensity, and previous characterlzatlon studies indicated that the emtsston was approxt- mately a black-body dlstnbutlon with temperature m the range 100-200 eV The grazing-Incidence reflectance of the mirror was calculated using the optlcal constants of gold listed m Ref 3 The transmittance of the parylene-D (CgH6C12) filters were calculated usmg the optlcal constant of carbon, oxygen, and chlorme derived from Ref 4 and assuming a density of I 42 g/cm’ The gratmg efficiency was calculated using scalar theory Durmg previous experiments using a newly-coated 349