High resolution beam line for the Grand Raiden spectrometer

T. Wakasa, K. Hatanaka, Y. Fujita, G. P.A. Berg, H. Fujimura, H. Fujita, M. Itoh, J. Kamiya, T. Kawabata, K. Nagayama, T. Noro, H. Sakaguchi, Y. Shimbara, H. Takeda, K. Tamura, H. Ueno, M. Uchida, M. Uraki, M. Yosoi

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117 Citations (Scopus)


We have designed and constructed a new beam line which can accomplish both lateral and angular dispersion matching with the Grand Raiden spectrometer. In dispersive mode, lateral and angular dispersions of the beam line are b16 = 37.1 m and b26 = -20.0 rad, respectively, to satisfy matching conditions for Grand Raiden. In achromatic mode, the beam line satisfies the double achromatic condition of b16 = b26 = 0. The magnifications of the beam line are (Mx, My) = (-0.98, 0.89) and (-1.00, -0.99) for dispersive and achromatic modes, respectively. In the commissioning experiments, we have succeeded to separate the first excited 2+ state of 168Er with Ex = 79.8 keV clearly from the ground state in the (p, p′) reaction. We achieved energy resolutions of ΔE = 13.0 ± 0.3 and 16.7 ± 0.3 keV in full width at half-maximum for 295 and 392 MeV protons, respectively. These energy resolutions agree with the resolving power of Grand Raiden for an object size of about 1 mm.

Original languageEnglish
Pages (from-to)79-93
Number of pages15
JournalNuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
Issue number1-3
Publication statusPublished - 2002 Apr 11


  • (p, p′) Reaction
  • Beam transport
  • Dispersion matching
  • Magnetic spectrometer


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