# Presentation: 777394

## Future ambitious plan of radio detections of highest energy cosmic rays

- H. Sagawa
- Institute for Cosmic Ray Research,
- University of Tokyo
- @ Brookhaven National Laboratory
- On April 10, 2008

- We have to prepare or think about the future project although we have just started data taking of Telescope Array!

- ~3000km2(~30times the size of
-                  AGASA)

**~10****3****km****2**

## Mission of the observatories of the highest energy cosmic rays

- Energy spectrum
- Anisotropy & point sources
- Correlation with AGNs?
- Chemical composition
- ⇒Astrophysics by using highest energy cosmic rays

## Extension of observatory of highest energy cosmic rays

- Search for point sources
- Number of cosmic rays of E>1020eV for five years
-     1 TA  (~103km2) ...      50 events    ~2x107 dollars
-   10 TA  (~104km2) ...    500 events    ~2x108 dollars
- 100 TA  (~105km2) ... 5,000 events    ~2x109 dollars
-                                    ( by AGASA energy scale )

## Future project of radio detection of ultra-high energy cosmic rays

- Merit of radio detection
- Basically 24h duty cycle, cheap, extensible
- Proposal: 100 times the size of the current TA
-                                     (105km2)

- R&D of radio detection of cosmic rays using the TA site
-   Obtain the information from the observation by TA
-     energy, arrival direction, Xmax
-   Reconstruction of cosmic rays by radio detection
-     Comparison with data byTA:
-           --> energy resolution, angular resolution,
-                Xmax resolution
-                trigger efficiency

## Radio that is emitted by air shower

- Askaryan effect
- Cherenkov effect in the medium such as ice and rock salt
- R&D for the experiment in the Antarctic
- This effect was measured.
- D.Saltzberg et al., PRL 86 (2001) 2802
- Other radios are dominant in the air
- Radio intensity is proportional to energy squared of primary cosmic rays
- Promising for very high energy cosmic rays
- FORTE, RICE, SALSA, GLUE, ....

## Our research items

- Geosynchrotron radiation from electrons that wind geomagnetic field (20-100MHz)
- More dominant than Askaryan effect in air
- Recently simulation is being developed.
- LOPES in KASCADE-Grande
- Radio from bremsstrahlung of electrons from air showers
- Microwave Molecular Bremsstralung Radiation (MBR)
- Detection of cosmic rays by radar

## Prototype of LOFAR: (prototype of SKA)

**Prototype of LOFAR: (prototype of SKA)**

## Our research items

- Geosynchrotron radiation from electrons that wind geomagnetic field (20-100MHz)
- More dominant than Askaryan effect in air
- Recently simulation is being developed.
- LOPES in KASCADE-Grande
- Radio from bremsstrahlung of electrons from air showers
- Microwave Molecular Bremsstralung Radiation (MBR)
- Detection of cosmic rays by radar

## Bremsstrahlung from quasi-thermal electrons from extensive air shower

**AMBER antenna**

**Bremsstrahlung from quasi-thermal electrons from extensive air shower**
**by atmospheric molecules**

## Our research items

- Geosynchrotron radiation from electrons that wind geomagnetic field (20-100MHz)
- More dominant than Askaryan effect in air
- Recently simulation is being developed.
- LOPES in KASCADE-Grande
- Radio from bremsstrahlung of electrons from air showers
- Microwave Molecular Bremsstralung Radiation (MBR)
- Detection of cosmic rays by radar

## RADARによる宇宙線観測

- A hit comes from observation of meteors by
- radar
- -->
-   **Plan of detectionn of air shower echo by using  MU radar of Kyoto University in Japan**

**Transmitter**

**Receivers**

## MARIACHI : Mixed Apparatus for Radar Investigation of Atmospheric Cosmic-Ray of Heavy Ionization

- By Helio Takai et al.

## Current organization in Japan

**The experts of meteor detection**
**by radar**

- Researcher of cosmic plasma

- +...

- MU radar  observatory

## MU radar

- (MU radar of Kyoto Univ.)
- 46.500MHz

- 475 sets of
- 2-element Yagi antennas
- phased-array system,
- 46.5MHz,
- Transmitter peak power: 1MW

## Possible CR echo?

- 26 Jan 2008

## Curren organization in Japan

**The Experts of lightning discharge detection**

- Theoretical calculations of radio emission

- +...

## Lightning discharge visualized with wide-band digital interferometer

- Lightning growth
- speed:
- 1.2~3.0×105m/s

*****

- Estimation of direction

- Estimation of direction

- 3-D position of lightning discharge

**Principle of 3-D reconstruction**

- 3-D reconstruction of lightning discharge by Kawasaki (Osaka Univ.)

## Plan in 2008

- Radar method
- Test observation of cosmic-ray echo by using MU radar, take data, improve detection method
- Development of production of the receivers if we get grant --> test with MU radar
- Check of TV radio wave and nosie level at TA site
- Method of detection of radiation ( geosynchrotron radiation, bremsstrahlung )
- Development and production of receivers if we get grant
- Performance test of the receivers together with scintillators in Japan

- Helio Takai is also thinking to check on radio detection using air shower by electron LINAC !

## Summary (characteristics of this research and the organization)

- Organization: TA group + various experts of methods analogeous to radio detections of cosmic rays + theorists of radiation calculation
- Meteor detection by radar --> observation of cosmic rays
- Lightning discharge observation --> observation of geosynchrotron radiation, bremsstrahlung of electrons from extensive air showers
- Research of various detection methods by one group
- The methods can be complementary.
- Evaluate energy resolution, angular resolution, Xmax resolution, trigger efficiency of radio detection by comparing with data from TA