1 / 30

The Cosmic Ray Air Shower and its Radio Detection

The Cosmic Ray Air Shower and its Radio Detection. 陈学雷 国家天文台. C osmic Ray Energy S pectrum. The maximum energy observed so far is about 3.2x10 20 eV eq. 50 J Many discoveries in particle physics: positron, muon, pion, Kaon, ... Now: astrophysical side. EAS Exp. O rigin of Cosmic Ray.

rachel-logan
Download Presentation

The Cosmic Ray Air Shower and its Radio Detection

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. The Cosmic Ray Air Shower and its Radio Detection 陈学雷 国家天文台

  2. Cosmic Ray Energy Spectrum The maximum energy observedso far is about 3.2x1020eV eq. 50 J Many discoveries in particle physics: positron, muon, pion, Kaon, ... Now: astrophysical side EAS Exp.

  3. Origin of Cosmic Ray Fermi acceleration

  4. Propagation of Cosmic Ray charged particle moving in random magnetic field E< 1015eV, confined around galaxy (some diffuse out)

  5. Puzzle of Ultra High Energy Cosmic Ray: the GZK cutoff Greisen 1966, Zatsepin & Kuzmin 1966

  6. Possible solutions • Incorrect measurement? Heavy nuclei? • produced nearby: superheavvy dark matter? topological defects? • produced nearyby: strong IGM magnetic field? • produced far away: neutrino? • produced far away: break down of relativity (violation of Lorentz invariance)?

  7. GZK or not?

  8. Detection of air showers • Ground Array: small area • emulsion, • scintillator, • water Cherenkov • Optical: low duty cycle • atmosphere Cherenkov • Fluorescence • radio: large area, high duty cycle

  9. Radio Signal EM wave ~ apparant acceleration of electric charge Negative charge excess in EAS and radio signal (Askayran 1962): production of delta-ray (knocked out electrons) annihilation of positron in flight • Geosynchrotron (Kahn & Lerche 1966) • charge seperation by geomagnetic field First detection (Jelley et al 1965) Review (Allan 1971), loss of interest Revival (Falcke & Gorham 2002) CASA-MIA, LOPES/LOFAR, CODALEMA

  10. Coherent Emission: Radio Pulse Radio pulse for a 1017 eV shower, at 0, 100,250 m from axis (Huege & Falcke astro-ph/0309622)

  11. Signal Strength Allan’s formula:

  12. Spectrum Monte Carlo Simulation by Huege & Falcke, astro-ph/0501580, at 20m, 140m, 260m,380m, 500m

  13. distribution and polarization 0o 30o 60o 90o total EW pol NS pol vertical pol

  14. Energy Dependence

  15. Background Noise Falcke & Gorham, astro-ph/0207226

  16. LOPES LOfar PrototypE Station

  17. KASCADE-Grande= KArlsruhe Shower Core and Array DEtector + Grande Measurements of air showers in the energy range E0 = 100 TeV - 1 EeV

  18. Progress LOPES-10 • 10 antennas at KASCADE array • frequency band 40-80 MHz • trigger: >10/16 cluster of KASCADE • ( E0 > 1016 eV) • 2004: 7 months runtime • ~630.000 triggered events • (and correlated EAS information) • sufficient sample of events for detailed analyses LOPES-30 LOPES-STAR, LOPES-Auger

  19. LOPES 10 Results LOPES collaboration, Nature 425 (2005) 313

  20. CODALEMA experiment COsmic ray Detection Array with Logarithmic ElectroMagnetic Antennas Auger Detector Nancay DAM current setup (astro-ph/0608550)

  21. Results

  22. Radio Detection in China • relatively easy and cheap • particularly suitable for UHECR • not yet well-developed, room for exploration • technology spin-off (application in military & technology)

  23. Road Map • (1) concept design • (2) preliminary test: site selection, RFI background, instrument basics • (3) prototype: 4-10 antenna • (4) after analyzing prototype data, decide what to do • (5) Large scale deployment: • core array for lower energy (10 17 eV) flux and sparse array for high energy. Area: 103-4 km2 with spacing 0.5-1 km.

  24. prototype proposal 已申请本年度天文联合基金（仪器研制类重点项目, 200万） PI: 陈学雷 coI:施浒立, 秦波等

  25. Preliminary Design • center frequency: 30 MHz • wide bandwidth or multi-band (to overcome artificial RFI which is usually narrow band) • multi-polarization loaded-dipole/half-wave antenna (ominidirectional, wide and smooth frequency response)

  26. Amplification: 30-40 dB (to 0.1 V signal) ADC: 10-100 MHz, 14 bit,

  27. Simulated detection rate

  28. Site Selection 西藏羊八井: coincidence test (AS, ARGO) but: (1) high altitude, (2) RFI, (3) too far 内蒙正镶白旗： good EM environment, nearby, logistics ready but need coincidence detector, est. 100k per piece (Cao Zhen)

  29. Plan ２００８年，研究大气簇射射电机制，设计模拟程序，进行天线和探测系统的初步设计、试制和实验室检测，对羊八井和正镶白旗站址进行测试， 对数据处理方法进行调研和初步设计；与国外有关研究人员联系，探讨国际合作研究的可能性。 ２００９年，完成大气簇射射电模拟程序并进行模拟研究，对天线和探测系统进行野外测试和优化，设计、调试数据处理软件，邀请国外有关专家参与实验。 ２０１０年，收集数据并进行分析处理，研究大规模宇宙线实验的可行性。

More Related