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Analyzing Composite Materials by Characteristic Radiation Yu. M. Burmistrova, S. V. Zuyeva, M. N. Lifanova, and V. M. Skorkina,* a

Institute for Nuclear Research, Russian Academy of Sciences, Moscow, 117312 Russia *e-mail: [email protected] Received November 12, 2017; revised November 12, 2017; accepted November 27, 2017

Abstract—Characteristic X-ray spectra of materials containing heavy-metal components irradiated with gamma rays are measured. The samples are irradiated with photons with energies of 122.06 keV (85.5%) and 136.47 keV (10.7%) emitted by a cobalt-57 source and include tungsten, lead, and bismuth plates and a sample of a radiation-protective composite material. The characteristic radiation from the samples and incident photons passing through the samples are detected with a low-background gamma spectrometer based on a highpurity germanium (HPGe) detector. The measured intensity of the characteristic X-ray radiation from the protective material amounts to 10% of that of the primary radiation. The elemental composition of the radiation-protective material is determined by peak positions in the spectra of the characteristic X-rays from the samples of W, Pb, and Bi. The analyzed composite material features Pb as the dominant heavy component, whereby the primary photon radiation from the source is attenuated by a factor of 3.7. The density of the lead component in the protective material was determined. Keywords: characteristic radiation, radiation-protective material, composite material, metals, photons DOI: 10.1134/S1063778818100034

1. INTRODUCTION Given the ever increasing number of potentially hazardous objects, one needs to analyze the characteristics of new composite materials toward developing individual protective devices against harmful anthropogenic factors. In order to reduce absorbed doses at irradiated sites and in space missions, new composite materials containing heavy metals are developed [1]. Penetrating radiation largely arises from gamma and beta radiation and neutrons. These can be efficiently absorbed by heavy components of composites and transformed to local X-ray and electron radiation. Special radiation-protective uniforms for firemen involve composite materials with lead and tungsten microparticles [2], whereby the absorption rate of external radiation is increased by several times. The absorption of gamma and beta radiation in protective materials helps reduce the energy and penetrating power of radiation, thus protecting the vital organs of personnel.

teristic X-rays and Auger and conversion electrons. Secondary electrons are almost fully absorbed by the heavy components of the composite, while the X-rays leave the composite material and are detectable. For probing the characteristic X-ray radiation of samples containing lead (75 and 85 keV), tungsten (59 and 67 keV), and bismuth (77 and 87 keV), we irradiate composite materials with photons with energies of

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2. EXPERIMENTAL METHOD Low-energy gamma rays interact with matter (such as a composite material) t