M. Hagiwara

Experimental studies on excitation functions of the proton-induced activation reactions on yttrium

Proton-induced activation cross-sections were measured for the (89)Y(p,x)(89,88,86)Zr, (89)Y(p,x)(88,87,87 m,86)Y, (89)Y(p,x)(85,83,82)Sr and (89)Y(p,x)(84,83)Rb reactions by a stacked foil technique in the energy range 15-80 MeV which was covered by two separate measurements for 15-50 and 32-80 MeV energy range with 50 and 80 MeV incident protons. The differences between the results of two irradiations were found within 6% in the overlapping energy regions. The production yields for the long-lived products like (88)Zr, and (88)Y are significantly larger than that of (nat)Mo+p, (nat)Nb+p and (nat)Zr+p processes. The productions of the medical isotopes, (85)Sr and (83)Sr are also effective by Y+p process using an 80 MeV beam. Thick target integral yields were also deduced using the measured cross-sections. The (87)Y, (88)Y, (88)Zr and (89)Zr radionuclides have suitable yields and decay characteristics important for thin-layer activation (TLA) analysis.

Experimental study of the excitation functions of proton induced reactions on natSn up to 65 MeV

Abstract Using the stacked-foil activation technique, cross-sections of proton induced reactions on natural Sn were determined up to 67xa0MeV. Excitation functions are reported for the first time for the product nuclides 109In, 110In, 111In, 114mIn, 113Sn, 117mSn, 115Sb, 120mSb. Comparison with low energy published data for reactions leading to 116mSb, 117Sb, 118mSb, 122Sb, 124Sb are discussed. For all excitation functions a theoretical calculation using the ALICE-IPPE code was performed. Relevance to the production of medically relevant radioisotopes (111In, 114mIn, 117mSn) is discussed.

Measurement of Neutron Emission Spectra in Li(d,xn) Reaction with Thick and Thin Targets for 40-MeV Deuterons

Abstract To improve the data accuracy of the neutron emission spectra of the natLi(d,xn) reaction that will be used as the neutron source in the International Fusion Materials Irradiation Facility, the authors have measured the neutron emission spectra from thick and thin lithium targets bombarded by 40-MeV deuterons at the AVF cyclotron (K = 110) facility of Tohoku University. The neutron spectra were measured at nine laboratory angles between 0 and 110 deg with the time-of-flight method using a beam-swinger system and a well-collimated neutron flight channel, obtained over almost the entire energy range of secondary neutrons using a two-gain method. The data obtained revealed the shape and angular dependence of emission spectra up to the high-energy region called a “high-energy tail.” The experimental results are compared with other experimental data and calculations.

New cross-sections for production of 103Pd; review of charged particle production routes

Production cross-sections of (103)Ag obtained by irradiating (nat)Pd and (nat)Cd with 70 MeV protons are presented and compared with ALICE-IPPE model calculations. Production of (103)Ag is of interest for the generation of (103)Pd widely used in brachytherapy. The investigated energy range of the (103)Rh(d,2n)(103)Pd reaction was extended up to 40 MeV and the results were compared with the curves of ALICE-IPPE, EMPIRE-II and GNASH theoretical codes. Thick target yields were calculated. An overview and analysis of the most important charged particle induced production routes of (103)Pd is presented. An explanation of the apparent discrepancy in the activity measurements for (103)Rh based on X- or gamma-ray is given.

Excitation functions for production of 88Zr and 88Y by proton and deuteron irradiation of Mo, Nb, Zr, and y

Cross sections for production of 88Zr and 88Y were measured for proton and deuteron induced nuclear reactions on Mo, Nb, Zr and Y targets up to 80 MeV proton and 50 MeV deuteron energy. Stacked foil activation technique and high‐resolution γ‐spectrometry were used for irradiation and for detection of the radioactive residuals. The experimental data up to Ep=100 MeV and for Ed=50 MeV were compared with the earlier literature data and with the theoretical calculations based on the ALICE‐IPPE code. Production yields of the different production routes are compared.

Experimental studies on the neutron emission spectrum and induced radioactivity of the 7Li(d,n) reaction in the 20–40 MeV region

To improve the data accuracy of the neutron emission spectrum of the 7 Li(d,n) reaction and the radioactivity ( 7 Be, 3 H, etc.) accumulated in the 7 Li target in IFMIF, we have measured the neutron emission spectrum and the radioactivity of Be induced in the lithium target for 25 MeV deuterons at the Tohoku University AVF cyclotron (K = 110) facility. Neutron spectra were measured with the time-of-flight (TOF) method at four laboratory angles by using a beam swinger system and a well collimated TOF channel. Induced radioactivity was measured by detecting the gamma-rays from Be with a pure Ge detector. Experimental results are compared with other experimental data. The present result of neutron emission spectra are in qualitative agreement with other experimental data but that of 7 Be production was much larger than expected by the recent codes. Measurement will be extended to several incident energies up to 40 MeV.

Measurements of Differential Thick Target Neutron Yields and 7Be Production in the Li, 9Be (d, n) Reactions for 25 MeV Deuterons

Neutron emission spectra and production rates of radioactive nuclide 7Be in the (d, n) reactions on thick lithium and 9Be targets have been measured for 25 MeV deuterons at the Tohoku University AVF cyclotron (K=110) facility to provide basic data for the design of the intense neutron source, International Fusion Reactor Material Irradiation Test Facility (IFMIF). Neutron spectra were measured with the time-of-flight method at ten laboratory angles between 0° and 90° by using a beam swinger system. Data were obtained down to ~1 MeV from the highest energy, using a two-gain NE213 detector system. Induced radioactivity of 7Be was measured by detecting the 478 keV γ-rays from 7Be with a pure Ge detector. The experimental results of neutron spectra revealed clearly the entire shape of the neutron emission spectrum and the angular dependence including so called “high energy tail” extending up to ~40 MeV. The present data at 0° are in reasonable agreement with corresponding value by Lone et al. at 23 MeV above ~5 MeV, but show large discrepancy in the lower energy region. The results of 7Be production for both nuclei were much larger than expected by the calculation with a recent code IRAC.

Differential cross sections on fragment (2 ≤ Z ≤ 9) production for carbon, aluminum and silicon induced by tens-of-MeV protons

The double-differential cross sections (DDXs) for the inclusive reactions producing heavy nuclei with Z = 2–9 (fragments) from carbon, aluminum, and silicon targets induced by 50 and 70 MeV protons are systematically measured at several angles (30°, 60°, 90°, and 135°) using a specially developed Bragg curve counter and the energy-time-of-flight method. The DDXs of a silicon target for the proton-induced reaction producing fragments heavier than lithium were measured for the first time. The present results are compared with past experimental data, the LA150 evaluated data by the Los Alamos group and several intranuclear cascade models (Bertini and ISOBAR), and the JAEA-version quantum molecular dynamics model (JQMD) coupled with the Generalized Evaporation Model (GEM), which are implemented in the Particle and Heavy Ion Transport code System (PHITS). The present results agree well with the past experimental data and LA150 data for α -particle production. For the fragments heavier than lithium, the present results show forward-peak angular distributions rather than isotropic ones stored in LA150. Calculations with the ISOBAR and GEM models well reproduced our experimental results except for light fragments especially in the high-energy region.

Investigation of activation cross sections of the proton induced nuclear reactions on natural iron at medium energies

Iron is one of the most important structural materials in every field of science, technology, industry, etc. Its application in a radiating environment requires the knowledge of accurate excitation functions for the possible reactions in question. By using the Thin Layer Activation technique (TLA) the knowledge of such data is also extremely important even in the case of relative measurements to design the irradiation (irradiation energy, beam intensity, duration) and also for radioactive safety estimations. The cross sections are frequently measured at low energies but there are unsatisfactory and unreliable data in the energy range above 40 MeV.

Excitation functions of proton-induced reactions on natSn and natCd: Relevance to the production of 111In and 114mIn for medical applications

Excitation functions of proton induced nuclear reactions were measured for application purposes up to 80 MeV proton energies on natural Cd and Sn targets. The measured excitation functions were compared with the experimental results reported in the literature and with the results of theoretical calculations using the ALICE‐IPPE code. In the present work we report on the excitation functions, the deduced integral yields and impurity levels related to the production of the medical radioisotopes of indium (111In, 114mIn). High energy production routes by using Cd, In and Sn targets are compared.