SINBAD ABSTRACT NEA-1552/34
Transmission Through Shielding Materials of Neutrons and Photons Generated by 52 MeV Protons
1. Name of Experiment: ------------------ Transmission Through Shielding Materials of Neutrons and Photons Generated by 52 MeV Protons (1981) 2. Purpose and Phenomena Tested: ---------------------------- Attenuation of secondary neutrons and photons generated by 52 MeV protons through shielding materials. Graphite, iron, water and ordinary concrete assemblies were studied to obtain information on the secondary neutron effects, needed for the design of high energy accelerator shielding. 3. Description of the Source and Experimental Configuration: -------------------------------------------------------- The experiments were performed at the FM cyclotron of Institute for Nuclear Study of University of Tokyo. The 52 MeV proton beam was extracted into the air through a 0.15-mm-thick stainless-steel window of the beam transporting duct and injected to the center of a 2.145-cm-thick graphite target placed 5 cm from the window. A thickness of the graphite target was sufficient to stop the 52 MeV protons which have a range of 1.6 cm. Most neutrons were generated by C-12(p,n)N-12 reaction (Q=-18.14 MeV). The diameter of proton beam was about 5 mm at the injecting point. The beam intensity was 1 to 2 nA. 4. Measurement System and Uncertainties: ------------------------------------ The transmitted neutron and photon spectra were measured in the forward direction along the proton beam axis with a 51-mm-diam and 51-mm-long NE-213 scintillation detector placed in contact with the rear face of the slabs. Exception were three measurements of graphite, performed in 1979, where the detector was placed on the extended axis at 3.45 m from the front target surface (not reported here). The number of protons incident on the target was monitored by a current integrator connected to the target. Angle-dependent source neutron from the graphite target were measured with the NE-213 system at 0, 15, 30, 45 and 75 degrees, and the photon spectra at 0 degrees. Only neutrons with energies higher than about 2 MeV were measured. An estimation of low energy neutrons may be needed for gamma calculations to take into account neutron induced gamma rays. The following are experimental uncertainties derived from [7]. Item Uncertainty Detector Placement < 1-cm Material Thickness Error < 1% Material Density Error < 1% Source Measurement Error like 21.4 cm Graphite-see Figure 2 Neutron Penetration Spectra As Shown with Figures of Data Results Gamma-ray Penetration Spectra As Shown.... Background Contributions at 3 m Neutron (3-10%) Gammas (40-70%) 5. Description of Results and Analysis: ----------------------------------- The neutrons and photons produced at the target were transmitted through slabs of graphite (21.4, 42.8 and 64.5 cm thick), iron (19.3, 38.6 and 57.9 cm), water (60 and 101 cm), and ordinary concrete (46, 69 and 115 cm). The pulse height distributions were converted to neutron and photon energy spectra by using the revised FERDO unfolding code [3] and the calculated response matrix. In the experimental geometries with the detector in contact with the shield, the background was considered to be negligible. In the case of 1979 graphite experiments (data are not included here) background room scattering was estimated with the detector at 3 m from the graphite assembly and a shadow bar between the assembly and the detector. Background radiation contributed between 3 and 10 % to the observed transmitted neutrons and between 40 and 70% to the transmitted photons. NE-213 spectral data are reported in tables lacking statistical errors. Data plots contained 1-sigma error bars and computational comparisons using ANISN and MMCR-U transport codes. Data for Neutron transmission are tabulated from 2.5 MeV and continue in 1 MeV steps to 35.5 MeV. Photon flux was measured from 0.25 MeV and are tabulated in steps of 0.25 MeV through 10 MeV. Calculations were performed by MORSE, ANISN, MCNP-4A, and MMCR-U codes using DLC58/HELLO, DLC119/HILO86, DLC87/HILO and ENDF/B-VI high energy cross-section libraries ([2], [4], [5]). 6. Special Features: ---------------- None 7. Author/Organizer ---------------- Experiment and analysis: Uwamino Y.(*), Nakamura T.(**) and Shin K.(***): (*) Institute for Physical and Chemical Research, Hirosawa 2-1, Wako 351-01, 188, Japan (**) Cyclotron and Radioisotope Center, Tohoku University, Aramaki, Aoba, Sendai, 980, Japan (***) Dep. of Nuclear Engineering, Kyoto University Sankyo, Kyoto, 606, Japan Compiler of data for Sinbad: I. Kodeli, OECD/NEA, 12 bd des Iles, 92130 Issy les Moulineaux, France Reviewer of compiled data: Hamilton Hunter, Radiation Shielding Information Center, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831-6362, fax 423-574-6182, e-mail: h3o@ornl.gov. 8. Availability: ------------ Unrestricted 9. References: ---------- [1] Shin K., Uwamino Y., Yoshida M., Hyodo T. and Nakamura T.: "Penetration of Secondary Neutrons and Photons from a Graphite Assembly Exposed to 52-MeV Protons," Nucl. Sci. Eng., 71, 294-300 (1979). [2] Uwamino Y., Nakamura T. and Shin K.: "Penetration Through Shielding Materials of Secondary Neutrons and Photons Generated by 52-MeV Protons," Nucl. Sci. Eng., 80, 360-369 (1982). [3] K. Shin et al., Nucl. Technol., 53, 78 (1981). [4] K. Hayashi, et al.: "Accelerator Shielding Benchmark Analysis and Future Items to be Solved", SATIF Proceedings of the Specialists Meeting, Arlington, USA, 28-29 April 1994, OECD 1995 [5] H. Nakashima, et al.: "Accelerator Shielding Benchmark Experiment Analyses", SATIF-2 Proceedings of the Specialists' Meeting, CERN, Geneva, Switzerland, 12-13 Oct. 1995, OECD 1996 [6] T. Nakamura and T. Kosako, Nucl. Sci. Eng., 77, 168 (1981) [7] Personal Contact w/ Katsumi Hayashi, Aug. 1997. [8] H. Nakashima et al., Benchmark Problems for Intermediate and High Energy Accelerator Shielding, JAERI 94-012 (Sept.1994). 10. Data and Format: --------------- DETAILED FILE DESCRIPTIONS -------------------------- Filename Size[bytes] Content ---------------- ----------- ------------- 1 p52-abs.htm 10.960 This information file. 2 p52-exp.htm 24.911 Description of Experiment. 3 P52-fig1.gif 8.668 Figure 1: Experimental arrangement. (preview) 4 P52-fig2.gif 11.479 Figure 2: Neutron spectra in graphite.(preview) 5 P52-fig3.gif 12.480 Figure 3: Neutron spectra in iron. (preview) 6 P52-fig4.gif 11.249 Figure 4: Neutron spectra in water. (preview) 7 P52-fig5.gif 11.389 Figure 5: Neutron spectra in ordinary concrete. (preview) 8 P52-fig6.gif 14.953 Figure 6: Photon spectra in graphite. (preview) 9 P52-fig7.gif 13.739 Figure 7: Photon spectra in iron. (preview) 10 P52-fig8.gif 12.853 Figure 8: Photon spectra in water. (preview) 11 P52-fig9.gif 13.523 Figure 9: Photon spectra in ordinary concrete. (preview) 12 P52-FIG1.TIF 19.741 Figure 1: Experimental arrangement. (high quality) 13 P52-FIG2.TIF 37.540 Figure 2: Neutron spectra in graphite. (high quality) 14 P52-FIG3.TIF 41.836 Figure 3: Neutron spectra in iron. (high quality) 15 P52-FIG4.TIF 25.386 Figure 4: Neutron spectra in water. (high quality) 16 P52-FIG5.TIF 30.323 Figure 5: Neutron spectra in ordinary concrete. (high quality) 17 P52-FIG6.TIF 40.544 Figure 6: Photon spectra in graphite. (high quality) 18 P52-FIG7.TIF 39.701 Figure 7: Photon spectra in iron. (high quality) 19 P52-FIG8.TIF 26.257 Figure 8: Photon spectra in water. (high quality) 20 P52-FIG9.TIF 31.531 Figure 9: Photon spectra in ordinary concrete. 21 J94_012.PDF 3.233.504 Reference 22 52P_1.PDF 630.515 Reference 23 52P_2.PDF 972.531 Reference File P52-EXP.htm contains the following tables: (1) Dimensions and compositions of materials, (2, 3) Neutron and Photon source spectra, (4, 5, 6, 7, 8, 9, 10, 11) Neutron and photon spectra transmitted through graphite, iron, water and concrete assemblies. Figures are included in TIFF format using LZW compression and GIF format (preview). Neutron and photon spectra are shown on figures with the measurement uncertainties.
