Measurement of some EAS properties using new scintillator detectors developed for the GRAPES-3 experiment
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- 作者：P.K. Mohanty ; S.R. Dugad ; U.D. Goswami ; S.K. Gupta ; Y. Hayashi ; A. Iyer ; N. Ito ; P. Jagadeesan ; A. Jain ; S. Karthikeyan ; S. Kawakami ; M. Minamino ; S.D. Morris ; P.K. Nayak ; T. Nonaka ; A. Oshima ; B.S. R
- 关键词：Cosmic rays ; Extensive air shower ; Particle detector ; Scintillation detector
- 刊名：Astroparticle Physics
- 出版年：2009
- 出版时间：February 2009
- 年：2009
- 卷：31
- 期：1
- 页码：24-36
- 全文大小：1498 K
文摘
The GRAPES-3 extensive air shower (EAS) array started operation with 256 scintillator detectors at Ooty in India. Each detector is viewed by a fast photomultiplier tube (PMT) mounted at a height of 60 cm above the scintillator. However, for further expansion of the array, an alternative readout of the scintillator using wave-length shifting (WLS) fibers is employed. This resulted in improved performance with a larger photon signal and a more uniform response. With the inclusion of a second PMT, the dynamic range for particle detection has been increased to 5 × 10<sup>3sup> particles m<sup>−2sup>. We now use plastic scintillators, developed in-house to cut costs. The measurement of the density spectrum, shows a power law dependence with an index γ = 1.57 ± 0.04. Using the zenith angle dependence of the density spectrum, an attenuation length Λ<sub>asub> = 98–106 g cm<sup>−2sup> for the EAS is obtained. These measurements are found to be consistent with the results reported earlier by other groups.