Ⅲ-3. Radiochemistry & Nuclear Chemistry

RIKEN Accel. Prog. Rep. 49 (2016)
Cross
checking of monitor reactions
at RIKEN AVF cyclotron using 50 MeV
alphaparticle beams

S. Takács,*1 F. Ditrói,*1 Z. Szűcs,*1 H. Haba,*2 Y. Komori,*2 M. Aikawa,*3,*2 and M. Saito*4,*2
In the frame of a bilateral agreement between theHungarian Academy of Sciences (HAS) and the Japan
Society for the Promotion of Science (JSPS), experiments
were performed to determine activation cross sections for avariety of radionuclides, which were produced in alphaparticle induced nuclear reactions on 27Al, natTi, natCu, natPd,natCd, 116Cd, and natGe target materials, using theconventional stacked-foil-target technique and activation
method. Experiments were performed during two separate
beam time allocations in January 2015 and in December
2015. In both series of experiments alpha particle beams
with Eα = 51.2 MeV energy were used, measured by thetime of flight method. Irradiations took place in a special
vacuum chamber for irradiation times of one or two hours
with a beam current of 50 nA. The activity of the irradiatedtarget foils was assessed by high purity Ge
gamma-spectrometers. Decay of the produced radionuclides
was followed for several half-lives in order to identify thesources of the possible interfering gamma radiations
accurately. Reactions on the 27Al, natTi, and natCu target
materials are most frequently used for monitoring the beam
parameters, such as actual beam energy, beam intensity, orenergy loss of the bombarding particles in the irradiatedtarget material. Recommended cross section values areprovided for those monitor reactions by the International
Atomic Energy Agency (IAEA)1) and are freely available on
the Internet. Since the recommended data available by
IAEA were evaluated one by one, independently, across-check of the reaction cross section is advised. The aimof our measurements regarding the 27Al, natTi, and natCu
targets was to contribute the cross-checked data sets to thedatabase maintained by the Nuclear Data Section (NDS),
IAEA and extend the energy range of the recommended
data up to 50 MeV, where necessary. A stack containing thin
Al, Ti, and Cu metallic foils was irradiated to cross-check
27
27
nat
Al(α,x)22Na,Al(α,x)24Na,Ti(α,x)51Cr,
thenat66
nat67
nat65
Cu(α,x) Ga, Cu(α,x) Ga, and Cu(α,x) Zn monitor
reactions. As indicated by the first preliminary results
shown in Figs. 1 and 2, there is only a small inconsistency
among the recommended values of the investigated monitor
reactions. Experimental data measured on 27Al, natTi, andnat
Cu in the same stack show that the recommended values
provided in the IAEA database are relatively in goodagreement. However, the shapes of the recommended
curves and the new experimental data show some deviations,which require further analysis and verification.
Institute for Nuclear Research, Hungarian Academy of Sciences
RIKEN Nishina Center＊3
Faculty of Science, Hokkaido University＊4
Graduate School of Science, Hokkaido University

Preliminary data show that the amplitude of therecommended excitation functions and the experimental
values have maximum difference of 7%, which should beconfirmed later, since some of the data collection is stillrunning and data evaluation is in progress.

Figure 1. Preliminary results are shown on cross section
data for the 27Al(α,x)22,24Na, natTi(α,x)51Cr, natCu(α,x)66,67Ga,
and natCu(α,x)65Zn reactions. Solid curves denote the IAEA
recommended values, which are in acceptable agreementwith our measurements; however, the shape of theexcitation functions should be confirmed.

Figure 2. Preliminary results are shown on cross section
data for the 27Al(α,x)22,24Na reactions. Solid curves denote
the IAEA recommended values. The shape of the excitation
functions should be confirmed.
Reference＊1＊21) https://www-nds.iaea.org/medical/monitor_reactions.html- 249 -