JAEA-Conf 2011-002 - 日本原子力研究開発機構

JAEA-Conf 2011-002
events can be identified through the
range-energy plot method [8]. The range
can be determined using the signal from
the cathode electrode. On the other hand,
the events within the dotted circle (ii)
have too high energy to be stopped in
BCC and penetrate it. The missed energy
can be compensated through off-line
analysis [9]. By using these two new
methods, the energy spectra can be
obtained for each fragment over 0.5
MeV/nucleon to tens of MeV.
Fig.3 Two dimensional plot of events at 30 from 80 MeV
The measured data were analyzed to
proton induced reaction on carbon
obtain energy spectra for each fragment
with Z, corrected for the effects of energy losses in sample and incident window, and normalized to solid
angle, the number of target atoms and the number of incident protons.
3. Results and discussion
From the measurements, we have obtained DDX data of fragments for proton-induced reactions on
C, N, O, Al, Ti and Cu at several beam energies between 40 and 300 MeV, and several laboratory angles
between 30 and 120. The spectra were obtained down to 0.5 MeV/u. Here, typical examples are shown as
preliminary data. Final results will be reported later.
Figure 4 shows the results of fragment DDX for the Al(p,X) reaction for Ep=200 MeV. The figure
shows Li, Be, B and C spectra for 30, 60, 90, 120 emission angles. The experimental results taken by
Machner et al. are also plotted for Li and Be emission. It should be noted that their data were obtained
using counter telescopes with Si detectors and cover the energy region only above 20 MeV. The present
data smoothly connect to their data. The figure clearly shows that two data are consistent with each other.
The low cutoff energies of the present data, < 0.5 MeV/u permits to cover the energy region with highest
yields. Therefore, the data provides not only spectrum information but also integral cross section,
experimentally. In addition, the present result has relatively continuous distribution shows high energy tail
that is observed in the other results for Li and Be emission [2-5]. Concerning B and C spectra, the peak
yields are comparable to Li and Be. The fact indicates that emission process of B and C are similar to that
of Li and Be.
Figure 5 shows the results for the C(p,xLi) reaction at 30 for Ep=40, 50, 70, 80, 140, 200 MeV.
A change of spectra shapes is observed with increasing incident proton energy. For relatively low incident
energies, 40 and 50 MeV, peak structures are observed around the high energy end above continuum
components. The energy differences between peak structures are close to the energy between the ground