Determination of integral cross sections of 3H in Al foils monitors irradiated by protons with energies ranging from 40 to 2600 MeV
Yu. E. Titarenko, V. F. Batyaev, M. V. Chauzova, I. A. Kashirin, S. V. Malinovskiy, K. V. Pavlov, V. I. Rogov, A. Yu. Titarenko, V. M. Zhivun, S. G. Mashnik, A. Yu. Stankovskiy
aa r X i v : . [ nu c l - e x ] S e p Determination of integral cross sections of H in Al foils monitors irradiated byprotons with energies ranging from40 to 2600 MeV
Yu.E. Titarenko , V.F. Batyaev , M.V. Chauzova ,I.A. Kashirin , S.V. Malinovskiy , K.V. Pavlov , V.I. Rogov ,A.Yu. Titarenko , V.M. Zhivun , , S.G. Mashnik and A.Yu. Stankovskiy NRC Kurchatov Institute − Institute for Theoretical and Experimental Physics, Moscow, Russia NRNU MEPhI (Moscow Engineering Physics Institute), Moscow, Russia Los Alamos National Laboratory, NM 87545, USA SCK · CEN, Boeretang, Mol, Belgium
Abstract
The results of H production in Al foil monitors ( ∼ mg/cm thickness) are presented. These foils have been irradiated in 15 × ∼ mg/cm thickness together with foilsof Cr ( ∼ mg/cm thickness) and F e ( ∼ mg/cm thickness)by protons of different energies in a range of 0.04 − −
10 under the ISTC Project − H has been extracted from Al foils using an A307 SampleOxidizer. An ultra low level liquid scintillation spectrometer Quantu-lus1220 was used to measure the H β − spectra and the SpectraDecsoftware package was applied for spectra processing, deconvolution and H activity determination. The values of the Al ( p, x ) H reaction crosssections obtained in these experiments are compared with data mea-sured at other labs and with results of simulations by the MCNP6radiation transport code using the CEM03.03 event generator. Introduction
Tritium is a gaseous product of nuclear reactions, whose formation, in addi-tion to the issues of radiation production in specific parts of nuclear instal-lations, causes additional environmental problems, associated with its highmigration ability. This stimulates an interest in the study of the productioncross-sections of this nuclide in different structural materials of nuclear in-stallations. A compilation of the experimental values of the cross-sectionsof the reaction Al (p,x) H , taken from data libraries [1, 2] and together withvalues obtained in this work in comparison with the simulated data both in[3] and in this work are presented in Fig. 1.
10 100 1000 100000.010.1110100
Mashnik, MCNP6(CEM03.03), NIM A764(2014) Lefort 1961,
Figure 1: Al (p,x) H reaction cross-sections measured in [1, 2], simulated [3] as wellas obtained in this work. A comparison of the simulated excitation functions of the Al (p,x) H reaction with various experimental data sets reveals that the mean squareddeviation factor < F > , often used to assess the predictive power of codes[4], is within the range from ∼ ∼
5. In addition to the above, the spreadof the experimental data is much wider than the experimental uncertainties.
Justification of the experiments, simulation andresults
During 2006 - 2009, under the framework of the ISTC Project Cr , F e , and other thin samples induced by 0.04 – 2.6 GeVprotons. All the samples were placed inside polyethylene bags together withAl foils to monitor proton flux. Both the samples and foils were thin enough( ≪ g/cm ) to get a negligible degradation of proton energy within each“sample-foil” sandwich. That is why the losses of residual nuclei heavier Be could be neglected. The main project results obtained by γ –spectrometryof the irradiated samples can be found in [4, 5].Subsequently, the idea arose to measure tritium inside the irradiatedsamples and foils. The event generator CEM03.03 inside the MCNP6.1.1transport code was used to simulate the spectra of tritium nuclei producedby the protons and showed that a significant part of produced tritium hasa range above the foils thickness (see Fig. 2).
10 100 10001E-61E-51E-41E-3 d / d E d ( ba r n / M e V / S r) E H (MeV) Al(Ep=1200MeV), 3H - 7.5(cid:176) Al(Ep=1200MeV), 3H - 167.5(cid:176) C(Ep=2600MeV), 3H - 7.5(cid:176) C(Ep=2600MeV), 3H - 167.5(cid:176) Cr(Ep=800MeV), 3H - 7.5(cid:176) Cr(Ep=800MeV), 3H - 167.5(cid:176) Fe(Ep=1600MeV), 3H - 7.5(cid:176) Fe(Ep=1600MeV), 3H - 167.5(cid:176)
Figure 2: Energy spectra at different angles of H nuclei released from the Al , C , Cr and F e nuclei irradiated by 1200, 2600, 800 and 1600 MeV protons, accordingly.
This fact leads to some redistribution of tritium produced in thepolyethylene, samples, and monitor layers through the exchange of tritiumnuclei. Therefore, the cross section results obtained in this work are notquite identical to the cross section for tritium production in Al presented in[1, 2]; we identify our results as “integral” cross sections. Nevertheless, asshown in this work, the obtained results can certainly be used to verify thenuclear models of radiation transport codes. H activity in Al foil was determined using a low-background spectro-metric α -, β -radiometer, Quantilus 1220, and a system of automatic samplepreparation, A307 Sample Oxidizer. An analysis of the measured β -spectrawas carried out with the SpectraDec code [6]. The formula for determiningthe reaction rate and cross-section production of H are presented in [5].All results were simulated using the CEM03.03 event-generator incorpo-rated in the radiation transport code MCNP6.1.1 [7]. The real parameters(thickness, diameter, density) of irradiated samples ( Al , Cr , F e ) weremodelled, including the thickness of polyethylene bags in the appropriatelayers-cells.
Simulated values of independent cross-sections of H production in Al [5],together with the calculations of the integral cross-sections and measuredvalues, are shown in Fig. 1. The values of < F > for Al from pair Cr ↔ Al are equal to 2.14 and 1.79 from pair F e ↔ Al (see details in [5]).The authors very much appreciate the support received from the ISTCprojects, as well as from the current pilot project of the National ResearchCenter “Kurchatov Institute”. Part of the work performed at LANL wascarried out under the auspices of the National Nuclear Security Adminis-tration of the U.S. Department of Energy. We thank Dr. Roger L. Martzfor a very careful reading of the manuscript and useful suggestions on itsimprovement. References [1]
Experimental Nuclear Reaction Data (EXFOR) database
Production of Radionuclides at Intermediate Energies , Ed. H.Schopper.Springer Verlag, Landolt-Bernstei.[3] S.G. Mashnik, L.M.Kerby,
NIM A , 764 (2014) 5981.[4] Yu.E. Titarenko, et. al.,
Physical Review. C , 84 (2011), 064612-12011.[5] Yu.E. Titarenko, et. al.,
IAEA Nuclear Data Section, INDC (CCP)-0453 , VIC, A-1400 Vienna, Austria, October 2011.[6] I.A. Kashirin, et al.,
Applied Radiation and Isotopes , 53, 303308 (2000).[7] M.R. James, et. al.,