TY - JOUR
T1 - Construction of polarized slow-positron beams using a compact cyclotron
AU - Kumita, T.
AU - Chiba, M.
AU - Hamatsu, R.
AU - Hirose, M.
AU - Hirose, T.
AU - Iijima, H.
AU - Irako, M.
AU - Kawasaki, N.
AU - Kurihara, Y.
AU - Matsumoto, T.
AU - Nakabushi, H.
AU - Omori, T.
AU - Takeuchi, Y.
AU - Washio, M.
AU - Yang, J.
N1 - Funding Information:
This research was partially supported by a Grant-in-Aid for Scientific Research from the Ministry of Education, Science, Sports and Culture of Japan and the Proposal-Based Advanced Industrial Technology R&D Program from the New Energy and Industrial Technology Development Organization (NEDO) of Japan.
PY - 1997/5
Y1 - 1997/5
N2 - We have constructed a polarized positron beam using positrons provided from the β + decay of 27 Si with the half-life of 4.1 s and the maximum β + energy of 3.85 MeV. This isotope is produced via the 27 Al(p, n) 27 Si reaction caused by proton irradiation using a compact proton cyclotron. The intensity of this beam is measured to be 5 × 10 5 e + /s for protons with the energy of 18 MeV and the current of 30 μA. A pair of Monte Carlo simulation programs has been developed to calculate depolarization of positrons in our beam channel. One program simulates spin motion of the positron under electric and magnetic fields, while the other simulates depolarization due to multiple Coulomb scattering in matter. Using these simulators, we designed a special polarimeter by means of magnetic quenching of ortho-positronium and measured a quenched lifetime of ortho-positronium under the magnetic field of 0.4, 2.5 and 4.0 kG leading to the average polarization of 33.4 ± 5.3%, which is consistent with the estimation based on the Monte Carlo simulations.
AB - We have constructed a polarized positron beam using positrons provided from the β + decay of 27 Si with the half-life of 4.1 s and the maximum β + energy of 3.85 MeV. This isotope is produced via the 27 Al(p, n) 27 Si reaction caused by proton irradiation using a compact proton cyclotron. The intensity of this beam is measured to be 5 × 10 5 e + /s for protons with the energy of 18 MeV and the current of 30 μA. A pair of Monte Carlo simulation programs has been developed to calculate depolarization of positrons in our beam channel. One program simulates spin motion of the positron under electric and magnetic fields, while the other simulates depolarization due to multiple Coulomb scattering in matter. Using these simulators, we designed a special polarimeter by means of magnetic quenching of ortho-positronium and measured a quenched lifetime of ortho-positronium under the magnetic field of 0.4, 2.5 and 4.0 kG leading to the average polarization of 33.4 ± 5.3%, which is consistent with the estimation based on the Monte Carlo simulations.
KW - Depolarization
KW - Ortho-like positronium
KW - Polarimeter
KW - Polarized beam
KW - Positron beam
UR - http://www.scopus.com/inward/record.url?scp=0031547812&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0031547812&partnerID=8YFLogxK
U2 - 10.1016/S0169-4332(96)00964-6
DO - 10.1016/S0169-4332(96)00964-6
M3 - Article
AN - SCOPUS:0031547812
VL - 116
SP - 1
EP - 6
JO - Applied Surface Science
JF - Applied Surface Science
SN - 0169-4332
ER -