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Journal Articles

Neutron spectrometry and dosimetry in 100 and 300 MeV quasi-mono-energetic neutron field at RCNP, Osaka University, Japan

Mares, V.*; Trinkl, S.*; Iwamoto, Yosuke; Masuda, Akihiko*; Matsumoto, Tetsuro*; Hagiwara, Masayuki*; Satoh, Daiki; Yashima, Hiroshi*; Shima, Tatsushi*; Nakamura, Takashi*

EPJ Web of Conferences, 153, p.08020_1 - 08020_3, 2017/09

 Times Cited Count:3 Percentile:92.06

To validate response of an extended range Bonner Sphere Spectrometer (ERBSS) with $$^{3}$$He proportional counter, neutron energy spectra were measured using an ERBSS in the quasi-mono-energetic neutron field at the Research Center for Nuclear Physics (RCNP). Using 100 MeV and 296 MeV proton beams, neutron fields with nominal peak energies of 96 MeV and 293 MeV were generated via $$^{7}$$Li(p,n)$$^{7}$$Be reactions. The energy spectra were measured at a distance of 35 m from the target. To deduce the corresponding neutron spectra from thermal to the nominal maximum energy, the ERBSS data were unfolded using the MSANDB unfolding code. At high energies, the neutron spectra were also measured by means of the TOF method using NE213 organic liquid scintillators. The agreement between ERBSS and TOF neutron spectra above 5 MeV is very good. Comparison in terms of ambient dose equivalent, H$$^{*}$$(10) between ERBSS and TOF values for both proton energies shows very good agreement.

Journal Articles

Comparison of Bonner Sphere responses calculated by different Monte Carlo codes at energies between 1 MeV and 1 GeV; Potential impact on neutron dosimetry at energies higher than 20 MeV

R$"u$hm, W.*; Mares, V.*; Pioch, C.*; Agosteo, S.*; Endo, Akira; Ferrarini, M.*; Rakhno, I.*; Rollet, S.*; Satoh, Daiki; Vincke, H.*

Radiation Measurements, 67, p.24 - 34, 2014/08

 Times Cited Count:13 Percentile:75.09(Nuclear Science & Technology)

In order to investigate the impact of the difference of the transport code on the response calculation of Bonner Sphere, EURADOS (European Radiation Dosimetry Group) initiated an exercise where six groups having experience in neutron transport calculations with the MC codes (MCNP, MCNPX, FLUKA, PHITS, MARS, or GEANT4) calculated the responses of a bare $$^{3}$$He proportional counter, a $$^{3}$$He proportional counter embedded in the middle of a 9 inch polyethylene sphere, and a $$^{3}$$He proportional counter centred in a 9 inch polyethylene sphere containing a lead shell, at neutron energies of 1, 10, 100, and 1,000 MeV.

Journal Articles

Characterization of quasi-monoenergetic neutron source using 137, 200, 246 and 389 MeV $$^{7}$$Li(p,n) reactions

Iwamoto, Yosuke; Hagiwara, Masayuki*; Iwase, Hiroshi*; Yashima, Hiroshi*; Satoh, Daiki; Matsumoto, Tetsuro*; Masuda, Akihiko*; Pioch, C.*; Mares, V.*; Shima, Tatsushi*; et al.

Progress in Nuclear Science and Technology (Internet), 4, p.657 - 660, 2014/04

The authors measured the neutron energy spectra of the proton incident reaction on the lithium target with 137, 200, 246 and 389 MeV protons at several angles (0$$^{circ}$$, 2.5$$^{circ}$$, 5$$^{circ}$$, 10$$^{circ}$$, 15$$^{circ}$$, 20$$^{circ}$$, 25$$^{circ}$$ and 30$$^{circ}$$), using a time-of-flight (TOF) method employing organic scintillators NE213 at the Research Center for Nuclear Physics (RCNP) of Osaka University. For the neutron energy spectrum at 0$$^{circ}$$, the ratio of the peak neutron intensity to the total one varied between 0.4 and 0.5 depending on the incident energy. In order to consider the correction required to derive the response in the peak region from the measured total response for high-energy neutron detectors, the authors showed the subtractions of H*(10) obtained at larger angles from the 0$$^{circ}$$ data in the continuum part. It was found that subtracting the dose equivalent at about 22$$^{circ}$$ from the 0$$^{circ}$$ data reduces the continuum component most efficiency.

Journal Articles

Measurement of neutron energy spectra behind shields for quasi-monoenergetic neutrons generated by 246-MeV and 389-MeV protons using a Bonner sphere spectrometer

Matsumoto, Tetsuro*; Masuda, Akihiko*; Nishiyama, Jun*; Harano, Hideki*; Iwase, Hiroshi*; Iwamoto, Yosuke; Hagiwara, Masayuki*; Satoh, Daiki; Yashima, Hiroshi*; Nakane, Yoshihiro; et al.

Progress in Nuclear Science and Technology (Internet), 4, p.332 - 336, 2014/04

Recently, many high-energy accelerators are used for various fields. Shielding data for high-energy neutrons are therefore very important from the point of view of radiation protection in high energy accelerator facilities. However, the shielding experimental data for high energy neutrons above 100 MeV are very poor both in quality and in quantity. In this study, neutron penetration spectral fluence and ambient dose through iron and concrete shields were measured with a Bonner sphere spectrometer (BSS). Quasi-monoenergetic neutrons were produced by the $$^{7}$$Li(p,xn) reaction by bombarding a 1-cm thick Li target with 246-MeV and 389-MeV protons in the Research Center for Nuclear Physics (RCNP) of the Osaka University. Shielding materials are iron blocks with a thickness from 10 cm to 100 cm and concrete blocks with a thickness from 25 cm to 300 cm.

Journal Articles

Response measurement of a Bonner sphere spectrometer for high-energy neutrons

Masuda, Akihiko*; Matsumoto, Tetsuro*; Harano, Hideki*; Nishiyama, Jun*; Iwamoto, Yosuke; Hagiwara, Masayuki*; Satoh, Daiki; Iwase, Hiroshi*; Yashima, Hiroshi*; Nakamura, Takashi*; et al.

IEEE Transactions on Nuclear Science, 59(1), p.161 - 166, 2012/02

 Times Cited Count:11 Percentile:69.17(Engineering, Electrical & Electronic)

In this study, responses of Bonner sphere spectrometer (BSS) for 245 and 388 MeV neutrons was measured at RCNP, Osaka University. The neutrons are generated in the $$^{7}$$Li(p,n) reaction and its spectra consist of a high-energy peak and a continuum down to the low energy. Therefore, the observed counts of BSS caused by the continuum need to be subtracted. Adjusting a Li target angle and a collimator position, 0 deg and 30 deg component of generated neutron are available. While the 0 deg component contains both the peak and the continuum, the 30 deg component is considered to contain only the continuum. Therefore, the response of the peak is obtained. The spectra were measured using the time-of-flight (TOF) method with a NE213 scintillator.

Journal Articles

Characterisation of quadi-monoenergetic neutron energy spectra using $$^{7}$$Li(p,n) reactions at 246-389 MeV

Iwamoto, Yosuke; Hagiwara, Masayuki*; Satoh, Daiki; Iwase, Hiroshi*; Yashima, Hiroshi*; Itoga, Toshiro*; Sato, Tatsuhiko; Nakane, Yoshihiro; Nakashima, Hiroshi; Sakamoto, Yukio; et al.

Proceedings of 10th Meeting of the Task Force on Shielding Aspects of Accelerators, Targets and Irradiation Facilities (SATIF-10), p.53 - 61, 2011/03

The neutron energy spectra penetrating 10 to 100 cm thick iron and 25 to 200 cm thick concrete shields have been measured using 138, 243 and 387 MeV quasi-monoenergetic neutron sources at the Research Center for Nuclear Physics (RCNP) facility, Osaka University. The source neutrons were produced from a 1 cm thick lithium target bombarded with 140, 245 and 388 MeV protons. Two types of NE213 liquid organic scintillators and Bonner ball neutron spectrometers were used for the neutron energy spectrum measurement. The TOF and unfolding methods were applied to estimate the energy spectra behind the shield in the peak energy region and continuous energy region, respectively. We have also measured the neutron energy spectra and angular distribution of the source neutron above 1 MeV in the angular range from 0$$^{circ}$$ to 30$$^{circ}$$ with the TOF method. All measured data were compared with the PHITS Monte Carlo calculations.

Journal Articles

Quasi-monoenergetic neutron energy spectra for 246 and 389 MeV $$^{7}$$Li(p,n) reactions at angles from 0$$^{circ}$$ to 30$$^{circ}$$

Iwamoto, Yosuke; Hagiwara, Masayuki*; Satoh, Daiki; Iwase, Hiroshi*; Yashima, Hiroshi*; Itoga, Toshiro*; Sato, Tatsuhiko; Nakane, Yoshihiro; Nakashima, Hiroshi; Sakamoto, Yukio; et al.

Nuclear Instruments and Methods in Physics Research A, 629(1), p.43 - 49, 2011/02

 Times Cited Count:21 Percentile:86.19(Instruments & Instrumentation)

The authors measured the neutron energy spectra of a quasi-monoenergetic $$^{7}$$Li(p,n) neutron source with 246 and 389 MeV protons set at seven angles (0$$^{circ}$$, 2.5$$^{circ}$$, 5$$^{circ}$$, 10$$^{circ}$$, 15$$^{circ}$$, 20$$^{circ}$$ and 30$$^{circ}$$), using a time-of-flight (TOF) method employing organic scintillators NE213 at the Research Center for Nuclear Physics (RCNP) of Osaka University. The energy spectra of the source neutrons were precisely deduced down to 2 MeV at 0$$^{circ}$$ and 10 MeV at other angles. The cross sections of the peak neutron production reaction at 0$$^{circ}$$ were on the 35-40 mb line of other experimental data, and the peak neutron angular distribution agreed well with the Taddeucci formula. Neutron energy spectra below 100 MeV at all angles were comparable, but the shapes of the continuum above 150 MeV changed considerably with the angle.

Oral presentation

Neutron spectra and dose measurement in quasi-mono-energetic high-energy neutron fields

Mares, V.*; Pioch, C.*; R$"u$hm, W.*; Iwase, Hiroshi*; Iwamoto, Yosuke; Hagiwara, Masayuki*; Satoh, Daiki; Matsumoto, Tetsuro*; Masuda, Akihiko*; Yashima, Hiroshi*; et al.

no journal, , 

Measurements of neutron spectra and neutron doses were performed in high-energy neutron fields at the Research Center for Nuclear Physics (RCNP), Osaka University, Japan, using two extended Bonner Sphere Spectrometers (BSS), a WENDI-II REM meter, a DARWIN dosimeter, an extended FUJI REM counter, and the time-of-flight (TOF) method employing NE213 liquid organic scintillators. The quasi-mono-energetic neutron fields were generated by the $$^{7}$$Li(p,n)$$^{7}$$Be reaction from a Li target, injected by 246 and 389 MeV protons. The BSS and TOF neutron energy spectra were folded with H*(10) fluence-to-dose conversion coefficients and the resulting values for the neutron ambient dose equivalent were compared with those directly measured by various other instruments used in this experiment. Agreement among all H*(10) neutron doses was very reasonable considering the complexity of the experiment.

Oral presentation

Calibration of a bonner sphere spectrometer in quasi-mono-energetic high-energy neutron fields

Pioch, C.*; Mares, V.*; R$"u$hm, W.*; Iwase, Hiroshi*; Iwamoto, Yosuke; Tamii, Atsushi*; Shima, Tatsushi*; Hatanaka, Kichiji*; Nakamura, Takashi*

no journal, , 

Calibration measurements for a Bonner sphere spectrometer with $$^{3}$$He proportional counter were performed in quasi-mono-energetic neutron fields at the Research Center for Nuclear Physics (RCNP) at the Osaka University. Neutron fields with nominal peak energies of 244 MeV and 387 MeV were generated via $$^{7}$$Li(p,n)$$^{7}$$Be reactions. The neutron spectra were determined by BSS measurements in the range from peak energy down to thermal energies using the MSANDB unfolding code, and three different sets of response functions calculated by GEANT4. The neutron spectra above 10 MeV were also measured by means of the time-of-flight (TOF) method applying NE213 liquid organic scintillators. Within the uncertainties involved in the experiment a remarkable overall agreement of the measurements and response calculations was observed.

Oral presentation

Bonner spheres calibration in quasi-mono-energetic high-energy neutron sources

Mares, V.*; Pioch, C.*; Iwamoto, Yosuke; Hagiwara, Masayuki*; Hatanaka, Kichiji*; Iwase, Hiroshi*; Masuda, Akihiko*; Matsumoto, Tetsuro*; R$"u$hm, W.*; Shima, Tatsushi*; et al.

no journal, , 

Calibration measurements for a Bonner sphere spectrometer (BSS) with $$^{3}$$He proportional counter were performed in quasi-mono-energetic neutron fields at the Research Center for Nuclear Physics (RCNP) at the University of Osaka, Japan. Neutrons with nominal peak energies of 134 MeV and 197 MeV were generated in lithium target. The neutron spectra were determined by BSS measurements in the range from peak energy down to thermal energies using the MSANDB unfolding code. Three different sets of response functions calculated by Monte Carlo codes GEANT4 and MCNP/LAHET were used. For calibration of the BSS, the remaining count rates resulting from neutrons E $$>$$ 10 MeV were compared to calculated count rates using the independently measured TOF spectra and the response functions of the Bonner spheres. Within the uncertainties involved in the experiment a remarkable overall agreement of the measurements and response calculations was observed.

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