Air shower detection using radio technique for the future huge ultra-high energy cosmic ray observatory

2015 Fiscal Year Final Research Report

• Project/Area Number: 25400296
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Particle/Nuclear/Cosmic ray/Astro physics
• Research Institution: The University of Tokyo
• Principal Investigator: Ikeda Daisuke 東京大学, 宇宙線研究所, 特任助教 (60584258)
• Co-Investigator(Renkei-kenkyūsha): TERASAWA TOSHIO 東京大学, 宇宙線研究所, 教授 (30134662) ; NAKAMURA TAKUJI 国立極地研究所, 教授 (40217857) ; SAGAWA HIROYUKI 東京大学, 宇宙線研究所, 准教授 (80178590) ; OGIO SYOICHI 大阪市立大学, 理学系研究科, 教授 (20242258)
• Project Period (FY): 2013-04-01 – 2016-03-31
• Keywords: 超高エネルギー宇宙線 / 電波エコー観測 / 電子線形加速器 / Telescope Array実験 / 国際研究者交流（米国）

Outline of Final Research Achievements

For the future huge ultra-high energy cosmic ray observatory, we studied the radio technique to detect the air shower. We picked up two methods, the bi-static radar echo technique and the observed radiation from the electron beam from the accelerator.
For the radar echo, we have developed two radio detectors and installed at the center of the Telescope Array (TA) site. By the stable observation together with the TA detectors, we have not found any signals induced by air showers. We checked the theory of the radio echo, and found an additional component to reduce the cross section, which is the neutral collision with the atmospheric molecule. By this effect, the radio emission become weaker than we expected.
The radio emission from the electron beam which we found previous measurement has been observed by the another three experiments. So we made the collaboration with them and carried out a theoritical model to explain the observed emission in wide frequency range, from 50MHz to 12GHz.

Free Research Field

超高エネルギー宇宙線物理