32nd International Cosmic Ray Conference, Beijing Observation of solar neutrons by using a very sensitive cosmic ray detector Mt. Sierra Negra, Mexico Yutaka Matsubara August 11, 2011 32nd International Cosmic Ray Conference, Beijing

List of Authors Y. Matsubara1, Y. Nagai1, Y. Itow1, T. Sako1, D. Lopez1. G. Mitsuka1, K. Munakata2, C. Kato2, S. Yasue2, M. Kozai2, M. Tsurusashi2, Y. Nakano2, S. Shibata3, H. Takamaru3, H. Kojima4, H. Tsuchiya5, K. Watanabe6, T. Koi7, J. F. Valdés-Galicia8, A. Hurtado8, O. Musalem8, E. Ortiz8, L. X. González9 1Solar-Terrestrial Environment Laboratory, Nagoya University, Japan 2Department of Physics, Shinshu University, Japan 3College of Engineering, Chubu University, Japan 4Faculty of Engineering, Aichi Institute of Technology, Japan 5High-Energy Astrophysics Laboratory, Riken, Japan 6Institute of Space and Astronomical Science, Japan Aerospace Environment Agency, Japan 7SLAC National Accelerator Laboratory, USA 8Instituto de Geofisica, Universidad Nacional Autónoma de México, México 9Institoto de Astrofisica, Óptica y Electrónica, Tonanzintla, México

Observation of solar neutrons charged particles Earth Sun neutral particle: neutron Magnetic field 太陽 M. A. Lee 1991 太陽 Study on particle acceleration by using solar neutrons which come straightly Neutrons are produced by accelerated ions

World-wide network of solar neutron telescopes 4600m 2770m 3135m 2003年3月・11月に設置作業。 4200m 4300m 5250m 3200m started by Muraki et al. and operated since November 2003 24 hour observing

Observation by different energies Geotail >50keV September 7, 2005 Observation by different energies >30MeV 30min Neutrons were observed for longer time than X-rays. neutron >60MeV Sako et al. 2006 30min Bolivia (SNT, NM) Mexico (SNT, NM)

Typical solar neutron telescope (SNT) Proportional counter neutron particle ID Scintillator: 30 to 40 cm （Energy） direction proton

SciCR 1.7m 3m KEK→FNAL 3m Scintillator bars 2.5cm x 1.3cm x 3m 116×64×2＝14848 We use SciBar （3m x 3m x 1.7m） for the cosmic ray observations at Sierra Negra. SciBar was used for the accelerator experiments. SciBar has much better sensitivity than the current solar neutron telescope and can measure the track of particles. Particle identity. Better energy and directional resolution.

INAOE The proposed plan Mexico city Sierra Negra Puebla Transport the SciBar from FNAL to the National Institute of Mexico (INAOE) at 2150m above sea level. (2) Measure cosmic rays at INAOE and complete data taking system. (2011 to 2012) (3) Transport the detector to Sierra Negra, 4600m a.s.l. and start observing solar neutrons. (2012 to 2013)

Preliminary experiment using mini-SciCR in 2010 20cm 20cm successful ! Test of the power supply and electronics for SciCR Measure cosmic ray backgrounds at Sierra Negra 　　　 determine trigger condition of the experiment and calculate the expected efficiency of SciCR

Prepare data acquisition system in Japan On-going !!  Should be ready for shipping in September

Work at FNAL in February and March 2011 Inside the experimental hut Remove fibers and pack scintillator bars and fibers Two planes (X and Y) make one unit

Work at FNAL in February and March 2011

The detector arrived at INAOE in April 2011

The work until the end of 2011 (1) To redirect the detector (2) To insert fibers has already started and will finish soon. is expected to finish in October 2011.

We measure cosmic rays in INAOE in 2011 All the hardware and on-line software should be confirmed before Sierra Negra. (after October 2011 )

Comparison with the current SNT 16σ Upper: Solar neutron event on September 7, 2005 (black), Simulation assuming the instantaneous emission for the SNT (red) SciCR Ⅰ2σ Lower: Simulation for the SciCR assuming the same Flare as above. 57σ 16σ: current SNT, 57σ for the SciCR

Summary SciCR (SciBar for the Cosmic Ray Observations) is a sensitive experiment using 15,000 scintillator bars. It works as a super sensitive solar neutron telescope, and a cosmic ray muon detector. The progress of the project is as scheduled: Observation of cosmic rays will start in the end of 2011 at INAOE (2,150m a.s.l. ) in Mexico. The observation of neutron will start in the late 2012 on Sierra Negra (4,600m a.s.l.). Solar maximum will be 2013 ! The aurhors thank the SciBar and SciBooNE group for allowing them to use SciBar for the cosmic ray experiment, and INAOE to give space to do cosmic ray experiment. See the posters: ID26 (Y. Nagai et al.) as a solar neutron telescope ID 373 (Y. Nakano et al.) as a muon detector

We put it on Mt. Sierra Negra (4,600m a.s.l.) LMT

Preliminary experiment using mini-SciCR in 2010 Trigger board VME DAQ board 64ch MAPMT Front-end board slide from Y. Takubu

SciCR will start in 2012 Some minor problem will be solved in one year