1. 1 Korean Ultra High Energy Cosmic Ray School Array Experiment Global Hands-On Universe 2007 National Astronomical Observatory, Mitaka, Tokyo, Japan 2007. 7. 14 Ewha Womans University Jongmann Yang On behalf of the COREA Collaboration COREA Project Co smic ray R esearch and E ducation A rray in Korea

2. 2 Cosmic ray What is cosmic ray? –Fundamental particles, nucleus, extra terrestrial electro magnetic radiations Observed composition: –50% proton, 25% alpha, 13% C/N/O nucleus, <1% electron, <0.1% gamma, heavy nucleus Discovery: 1912 Victor F. Hess (Austria), 1936 Nobel prize AMS, EUSO CREAM AGASA, AUGER, COREA

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4. 4 Cosmic Ray Ground Array Projects Array Projects –AGASA and HiRes: Previous –AUGER and TA: Current –Schools Arrays: Nebraska, LA, Italy, Seattle, Paris, Lisbon, Stockholm, London, etc <= GPS is routinely available since 2002 Korean Strength (2840 junior high schools/ 1987 Senior high schools) Compact Geological Distribution of Schools High Speed Internet Network Best Human Resources in Science

5. 5 California HIgh school Cosmic ray ObServatory San Gabriel Valley 37 sites active San Fernando Valley 33 sites active NALTA North American Large area Time coincidence Arrays

6. 6 Experimental Concept of COREA Shower by atmospheric interaction Ground Observation (COREA School Array) Space Observation (MEMS satellite) AGASA COREA

7. 7 Three Goals of COREA Project Basic Science Project Science Education in High Schools Popular Science Project Participation of Many Students and General Public Ist Class Science Project & Korean Technologies Official Web Page Official Web Page http://www.corea-korea.org COREA (Cosmic ray Research and Education Array in Korea)

8. 8 Content of COREA Project Network of Surface Detectors at Nationwide High Schools –1~2 Detector at Each School Team of Students and a Teacher, Production, Operation, DAQ –System (Detector + PM tube + Electronics + PC) + (Internet + GPS + S/W) First Korean R&E Model of Big Science - Uijeongbu Science High School supported by KOSEF (2006.5 – 2007.2) PS Elec PC GPS Plastic Scintillator

9. Back Side Front Setup of Detector Stations Three detector stations The total detection area: 6m 2 Roof of Uijeongbu Science High School Cosmic Ray

10. 10 Plastic Scintillation Detector Depth : 1 cm Length : 100 cm Width : 100 cm 22 fibers

11. 11 GPS Receiver COREA Electronics GPS Antenna GPS Antenna Cable Low voltage operation : 3 V High timing performance < 2ns VIC-100, Synergy Systems, USA GPS Antenna & Receiver

12. 12 Data Acquisition Program Trigger modes by FPGA 0CH1 and CH2 and CH3 and CH4 1CH1 and CH2 and CH3 or CH1 and CH2 and CH4 or CH1 and CH3 and CH4 or CH2 and CH3 and CH4 2CH1 and CH2 and CH3 or CH1 and CH2 and CH4 3CH1 and CH2 and CH3 4CH1 and CH2 or CH1 and CH3 or CH1 and CH4 or CH2 and CH3 or CH2 and CH4 or CH3 and CH4 5CH1 and CH2 or CH1 and CH3 or CH1 and CH4 6CH1 and CH2 or CH1 and CH3 7CH1 and CH2 8CH1 or CH2 or CH3 or CH4 9CH1 or CH2 or CH3 10CH1 or CH2 11CH1 only 12CH2 only 13CH3 only 14CH4 only

13. Event Data Example 7 * 256 + 214 = 2006 GPS Time Data Year 7*256 + 214 = 2006 Month12 Day6 Time18:34:17 Nanosecond3*256 3 + 34*256 2 + 208*256 + 98 ADC Data gathered from four Detectors column 2Channel 1 Data column 3Channel 2 Data column 4Channel 3 Data column 5Channel 4 Data Event Data 1023 0 02 μsec Waveform Waveform of one event 10ns

14. Preliminary Experiment The same particle Two particles originated from one air shower Vertical arrangement Horizontal arrangement Confirmation of coincidence between two detectors in independent systems

15. Result & Analysis(1) 17,827 coincident(< 1 sec) events were recorded for 50 min by three detector stations. 17,827 events / 50 min (6 events / sec) Jan 15, 2007 20:00-20:50 Number of events 0.5 sec maximum time difference (within 1 second)

16. 16 55 events Number of events 0.0125 sec 360 events Enlarge 40 times Figure 1 Figure 2 Result & Analysis(2) 55 events are piled up close to the origin.

17. 17 With 55 events clustered within 150 ns of time interval, and assuming that the signal is due to a single high-energy cosmic ray, we estimate that the primary particle energy is around 1 TeV. The time differences of 100ns are caused by error of the oscillator in readout board. Result & Analysis(3) 10 -6 sec Enlarge 12500 times Number of events 55 events 1 TeV cosmic rays Figure 2 Figure 3

18. 18 DSC09457 One teacher and four students of Uijeongbu Science High School with professors and students of Ewha Womans University Feb 2007

19. 19Summary Three detector stations had been set up at Uijeongbu science high school, each detector station with four plastic scintillation detectors. Coincidence signals were detected by three detector stations. Install more detector stations at Ewha University and Yonsei University to detect higher energy cosmic rays. Plan to construct large-scale ground array by distributing set of detector stations over high schools in Seoul and South Korea in the near future.

20. 20 COREA Collaboration Junior High ( )Senior High ( )Univ. ( ) Others (1) (2) (1) ( ) (2) (8) (2) (3) (1) (4) (6) (2) (3) (1) (2) (1) 6 6 14 15 15 41 3 3 Total 38 schools & Labs. 65 people Students are not included in the statistics.