A superconducting solenoidal spectrometer for a balloon-borne experiment

• Published in: Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment Vol. 443; no. 1; pp. 71 - 100
• Main Authors: Ajima, Y., Anraku, K., Haga, T., Higashi, Y., Honda, H., Imori, M., Inaba, S., Kimura, N., Kobayashi, M., Makida, Y., Matsui, N., Matsumoto, H., Matsunaga, H., Motoki, M., Nozaki, M., Nishihara, Y., Nishimura, J., Orito, S., Otoba, M., Saeki, T., Sanuki, T., Sasaki, M., Shimamura, K., Suzuki, J., Suzuki, K., Takimi, N., Tanaka, K., Tsunoda, T., Ueda, I., Yajima, T., Yamagami, T., Yamamoto, A., Yamaoka, H., Yoshida, T., Yoshimura, K.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 21.03.2000
• Subjects: Balloon-borne payload; BESS; Magnetic-rigidity spectrometer; Thin superconducting solenoid; 29.30.Aj; Balloon-borne payload; Magnetic-rigidity spectrometer; 07.75.+h; Thin superconducting solenoid; 95.85.Ry; BESS; 95.55.Vj
• ISSN: 0168-9002; 1872-9576
• DOI: 10.1016/S0168-9002(99)01010-4

The BESS detector is a new type of balloon-borne spectrometer which utilizes various technologies recently developed for collider experiments. The principal scientific objectives include a measurement of cosmic-ray antiproton spectrum, search for anti-nuclei in cosmic radiation, and precise meaurements of cosmic-ray primaries. A thin superconducting solenoidal coil produces a uniform magnetic field of 1 T. Cylindrical drift chambers are located inside and outside the coil and perform continuous tracking. The momentum resolution is 0.5% at 1 GeV/c. i.e., the maximum detectable rigidity is 200 GV. Scintillation counter hodoscopes, placed above and below the solenoid, provide timing and d E/d x measurements and trigger generation. The timing resolution is 80 ps/counter. This cylindrical configuration achieves a large geometrical acceptance of 0.35 m 2 sr which is essential to detect rare cosmic-ray particles. In order to cope with high trigger rate and large data size, intelligent trigger circuits and a fast and parallel data acquision system are also developed. In 1993, the first scientific flight of the BESS apparatus was carried out and the first mass-measured antiprotons were detected at energies below 500 MeV