Construction of polarized slow-positron beams using a compact cyclotron

T. Kumita, M. Chiba, R. Hamatsu, M. Hirose, T. Hirose, H. Iijima, M. Irako, N. Kawasaki, Y. Kurihara, T. Matsumoto, H. Nakabushi, T. Omori, Y. Takeuchi, Masakazu Washio, J. Yang

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

We have constructed a polarized positron beam using positrons provided from the β+ decay of 27Si with the half-life of 4.1 s and the maximum β+ energy of 3.85 MeV. This isotope is produced via the 27Al(p, n)27Si reaction caused by proton irradiation using a compact proton cyclotron. The intensity of this beam is measured to be 5 × 105 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.

Original languageEnglish
Pages (from-to)1-6
Number of pages6
JournalApplied Surface Science
Volume116
Publication statusPublished - 1997 May
Externally publishedYes

Fingerprint

Cyclotrons
Positrons
cyclotrons
positrons
Depolarization
positronium
depolarization
Protons
Magnetic fields
Proton irradiation
Polarimeters
proton irradiation
protons
polarimeters
magnetic fields
Isotopes
half life
simulators
Quenching
simulation

Keywords

  • Depolarization
  • Ortho-like positronium
  • Polarimeter
  • Polarized beam
  • Positron beam

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films
  • Condensed Matter Physics

Cite this

Kumita, T., Chiba, M., Hamatsu, R., Hirose, M., Hirose, T., Iijima, H., ... Yang, J. (1997). Construction of polarized slow-positron beams using a compact cyclotron. Applied Surface Science, 116, 1-6.

Construction of polarized slow-positron beams using a compact cyclotron. / Kumita, T.; Chiba, M.; Hamatsu, R.; Hirose, M.; Hirose, T.; Iijima, H.; Irako, M.; Kawasaki, N.; Kurihara, Y.; Matsumoto, T.; Nakabushi, H.; Omori, T.; Takeuchi, Y.; Washio, Masakazu; Yang, J.

In: Applied Surface Science, Vol. 116, 05.1997, p. 1-6.

Research output: Contribution to journalArticle

Kumita, T, Chiba, M, Hamatsu, R, Hirose, M, Hirose, T, Iijima, H, Irako, M, Kawasaki, N, Kurihara, Y, Matsumoto, T, Nakabushi, H, Omori, T, Takeuchi, Y, Washio, M & Yang, J 1997, 'Construction of polarized slow-positron beams using a compact cyclotron', Applied Surface Science, vol. 116, pp. 1-6.
Kumita T, Chiba M, Hamatsu R, Hirose M, Hirose T, Iijima H et al. Construction of polarized slow-positron beams using a compact cyclotron. Applied Surface Science. 1997 May;116:1-6.
Kumita, T. ; Chiba, M. ; Hamatsu, R. ; Hirose, M. ; Hirose, T. ; Iijima, H. ; Irako, M. ; Kawasaki, N. ; Kurihara, Y. ; Matsumoto, T. ; Nakabushi, H. ; Omori, T. ; Takeuchi, Y. ; Washio, Masakazu ; Yang, J. / Construction of polarized slow-positron beams using a compact cyclotron. In: Applied Surface Science. 1997 ; Vol. 116. pp. 1-6.
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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, Masakazu

AU - Yang, J.

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N2 - We have constructed a polarized positron beam using positrons provided from the β+ decay of 27Si with the half-life of 4.1 s and the maximum β+ energy of 3.85 MeV. This isotope is produced via the 27Al(p, n)27Si reaction caused by proton irradiation using a compact proton cyclotron. The intensity of this beam is measured to be 5 × 105 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 27Si with the half-life of 4.1 s and the maximum β+ energy of 3.85 MeV. This isotope is produced via the 27Al(p, n)27Si reaction caused by proton irradiation using a compact proton cyclotron. The intensity of this beam is measured to be 5 × 105 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.

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