Design of the LORD Experiment and Perspectives of Ultra-High Energy Particles Observation G. A. Gusev, V. A. Chechin, B. N. Lomonosov, N.G.Polukhina, and V. A. Ryabov. P. N. Lebedev Physical Institute, Russian Academy of Sciences Arena2010

Outlook of Presentation Problems of ultrahigh-energy cosmic rays and neutrinos observation. LORD space experiment and design of apparatus The results of Monte Carlo simulation Conclusion Arena2010

The Main Goal of the LORD Experiment The primary goal of the LORD experiment is the detection of ultrahigh-energy cosmic rays and neutrinos. An investigation of the nature and spectra of cosmic particles with energies E ≥ 1020 eV (“ultra-high energies”, UHE) is one of the “hottest” problems of modern science. Information on these particles is important for solving fundamental problems of astrophysics and particle physics relating to cosmic ray sources and acceleration mechanisms, nature of dark matter, and space-time structure. Arena2010

Brief Description of the Main Goal of the LORD Experiment Currently we have a very controversial and paradoxical situation in UHE region. We know neither the nature of UHE particles, nor their sources or processes where they were accelerated to such extremely high energies. Arena2010

Experimental Results are Contradictories Moreover, the many facts of the experimental observations at different CR detectors contradicts to the current understanding of the Universe, because a flux of these energetic particles must be suppressed, owing to the GZK CR spectrum cutoff (EGZK ≈ 7∙1019 eV) caused by the interaction with microwave cosmic background. For resolving these contradictions, new independent measurements are necessary. HIRES – AUGER controversy? 1002.1975 astro-ph Arena2010

Neutrino Fluxes from Astrophysical Sources and the Decay of Super-massive Particles Arena2010

Neutrino Fluxes in the Top-down Decay Scenario of X-particles Barbot C, Drees M, Halzen F, Hooper D Phys.Lett. B 555 22 (2003); hep-ph/0205230 Arena2010

The Radio Method for Detection Ultrahigh-energy CRs and Neutrinos The idea of the radio method dates back to the paper by Askaryan, who showed that the propagation of high-energy cascades is accompanied by coherent Cherenkov radio emission. The development of cascades at high energies is determined by pair production and bremsstrahlung in the Coulomb field of charge-symmetric atomic nuclei. However, a significant number of shower particles have energies below some critical value (Ec ≈ 73 MeV in ice) at which the electrons of the medium also become a target for the interactions A combination of these processes gives rise to shower charge asymmetry. As follows from calculations, this excess of negative charge in the shower is ~20–30% of the total number of electrons. The electrons of the excess with energies above the Cherenkov threshold emit electromagnetic waves in a wide wavelength range. Arena2010

The Radio Method for Detection Ultrahigh-energy CRs and Neutrinos The application of the radio method is especially appropriate at ultrahigh energies since the power of coherent radio signal increases as a square of the shower energy. The most important advantage of the radio method is the possibility to scan over huge volumes of radio-transparent media providing detection of rare ultrahigh-energy events with relatively high statistics. Arena2010

The Radio Method for Detection Ultrahigh-energy CRs and Neutrinos Currently radio method is used as the basis for a number of experiments and projects on the ultrahigh-energy particle detection in such radio-transparent media as the atmosphere, salt domes and ice sheets of Antarctic and Greenland. Arena2010

Current Initiatives on UHECR and UHEN Radio Detection Ice: RICE - ongoing, started in 1996 FORTE, was active in 1997—1999 ANITA – ongoing Salt: SALSA – proposal (testbed) SND – proposal (testbed) Moon: KALYAZIN (suspended) GLUE was active in 1998 LORD – proposal 2004, now under construction EAS: LOFAR - ongoing Arena2010

Sketch of LORD Experiment Cosmic rays, neutrino interact with regolith and produce coherent Cherenkov radiation pulse, which after refraction on the Moon surface goes out to vacuum. It can be observed by satellite apparatus, amplitude, polarization, frequency spectrum being measured. Arena2010

LORD Space Experiment Height of orbit – 500-700 km Spacecraft Spacecraft Moon Moon Height of orbit – 500-700 km Exposition Time ~ 2 years Energy range of particles detection > 1020eV Arena2010

Block Diagram of LORD Detector RF-1 Flight Payload Controller Data Acquisition System 2 Gsps, 10 bit, 2 x 4096 samples Scientific instruments Calibration RF-2 Antenna System 27 V Spacecraft 16 Mbyte memory Power Supply Commands Data Arena2010

Antenna System ANTENNA SYSTEM: Two antennas + LNA Polarization - LP & RP 200 MHz - 800 MHz Gain ~ 7.5 dB Length =1515 mm Diameter= 600 mm LNA gain ~ 40 dB, NF~1.1 dB Low Noise Amplifier Low Noise Amplifier 1515 mm 1515 mm Ø 600 mm Ø 600 mm Arena2010

Low Noise Amplifier 200-800 MHz, NF=1.1 dB, Gain = 40 dB Sw1 BPF 200-800 MHz from the antenna to Data Acquisition System Sw2 Attenuator Noise Generator Noise Generator - ON Antenna- ON Arena2010

Block Diagram of Analog Part (Data Acquisition System) from LNA-1 to ADC-1 from LNA -2 to ADC-2 to antenna-1 to antenna-2 Arena2010

Block Diagram of Digital Part (Data Acquisition) from analog 1 to spacecraft from analog 2 2 channels: ADC (2Gsps, 10-bit) Buffer 4k x 10 bit (2048 ns) Memory 16 Mbytes Arena2010

Electronics Box L×W×H = 420 mm ×320 mm×80 mm, Weight= 12 kg, Power Supply = 27 V, 60 W Arena2010

Space Module LUNA-GLOB Arena2010

Monte Carlo Simulation Registration apertures of CR and neutrino with energies 10^18-10^25 by Monte Carlo method for different targets were calculated. It was supposed, that apparatus was at the altitude 1000 km. Monte Carlo Simulation Electric fields of Cherenkov radio emission was calculated according to the usual Zas parameterization Ef(μV/mMHz)=[N*ETs/Rs]sinϑsinϑc exp(-α(E)(cos ϑ- cos ϑc)2), where N=(N0/ρ)(f/f0)/(1+ (f/f0)1.44), f0=3,3GHz, cos ϑc =1/n is cosine of Cherenkov angle, n is refraction index, ϑ is polar angle between cascade direction and radiation, Rs is distance between antenna and radiation refraction point, Ts is transmision coefficient for longitudinal polarization, E is cascade energy in TeV, f is frequency in GHz, ρ is density of the media, N0=1.05 10-4 μV/mMHz , , Arena2010 представлено на Рис.3.

The Radio Signal Reflection from the Regolith-basalt Boundary Cascade produces Cherenkov radio emission, which propagates up and down. Up-going radiation goes out in vacuum and reflects down to basalt-regolith boundary and then reflects second time. Down-going radiation being reflected from basalt-regolith boundary goes out to vacuum. Taking into account of reflected signals is very important. Direct radiation Reflected radiations Regolith, n=1,73 ν, CR cascade Basalt, n=3 Moon Arena2010

The Results of Simulation for Direct and Reflected Signals This example shows, that there are cases, when reflected signal is short, that is its spectrum is more large, as comparing with direct signal. Arena2010

Direct and Reflected Pulses (Long Time-delay) This example shows, that there are cases, when reflected signal has long time-delay relative direct signal. Arena2010

Middle Time-delay, Middle Amplitudes, Short Reflected Pulse Arena2010

Short and More Intensive Reflected Pulse Arena2010

Direct and Reflected Pulses (Short Time-delay), both Pulses Strong Arena2010

Direct and Reflected Pulses (Short Time-delay), Strong Direct Pulse and Weak Reflected Pulse Arena2010

CR Events on Visible Area of Moon nadir angle azimuthal angle Νev=F(Θnadir, φazimut) Arena2010 Red squares – direct signals and blue ones – reflected signals

Integral event number as function of particle energy for CR Detector threshold is about 1020 eV. Integral count rate is about 320 events. Arena2010

Simulation of Neutrino Detection for flux of massive particle decays Numbers of events Mass of X-paticle 2· 1025 eV, Satellite altitude – 700 km, Regolith layer – 2-12 m, SNR=6 (threshold – 100 μV) Arena2010

Apertures CR and Neutrinos as Function of Particle Energy Blue curve corresponds regolith, and red one – basalt. Maximum aperture for CR is 3·105 km2 sr. Maximum aperture for neutrino is 105 km2 sr. Arena2010

Limits for CR and Neutrino Fluxes Arena2010

Conclusion LORD is elaborated and now under construction. The additional contribution of reflected signal greatly enhances the scientific potential of experiments with the lunar orbital radio detector. LORD apertures for UHECR & UHEN detection are higher than in all ongoing experiments and for energy 1021 eV are about 3·105 km2 sr for UHECR and 105 km2 sr for UHEN The work is performed with partial support of grant RFBR 08-02-00515 and Program of Russian Academy of Sciences “Neutrino Physics”. Arena2010

Expected “Luna-Globe” launch 2012 Arena2010

Thank you for attention Arena2010