JEM-EUSO: frontier astroparticle physics @ ZeV from Space Print E-mail

ImageCosmic rays getting into the atmosphere give birth to a particle shower that can be detected by ground detectors… Or even by a space telescope! This is the challenge of JEM-EUSO...



JEM-EUSO is a downward looking telescope project, which will be onboard the International Space Station (Credit JEM-EUSO collaboration).

The JEM-EUSO refractive telescope is an extremely fast, highly pixelated, large-aperture, super-wide Field-of-View (FoV ±30°) digital camera. It comprises two double-sided curved Fresnel lenses and a diffractive plane, to observe the time and space resolved atmospheric fluorescence tracks produced, in the near UV range (330-400 nm) by the extensive air showers, with 2.5 μs time resolution and about 0.75 km spatial resolution (0.1º). The focal surface of the JEM-EUSO telescope is formed by about 6,000 photomultipliers with nearly 200,000 pixels. The technological key issues of JEM-EUSO are mainly the implementation of the new lens material and an improved optical design, detectors with higher quantum efficiency and an improved algorithm for event trigger.

The JEM-EUSO collaboration is presently an international joint effort of 12 countries (Japan, USA, France, Italy, Germany, Switzerland, Russia, Republic of Korea, Mexico, Spain, Poland and Slovakia) and about 200 researchers. It is being conducted by RIKEN and the Japan Aerospace eXploration Agency (JAXA). Europe, with a long-standing tradition in the previous EUSO plays a key role with Seven countries involved.

JEM-EUSO is currently completing the Phase A/B of JAXA design study and it will be launched in 2013-2015 by the Japanese H-IIB rocket and conveyed to ISS by the transfer vehicle HTV. The overall estimated cost of the JEM-EUSO telescope is around 150 M€.

Opening an ultra-high energy window on an unexplored Universe could reserve exciting surprises. Onboard ISS, JEM-EUSO will be ready for surprises at the ZeV scales.

The atmosphere as a detector

cosmic rays showerBefore reaching the Earth’s surface, cosmic rays interact with the constituents of the atmosphere, changing their nature and energy. A large variety of secondary particles, which decay or make new collisions, is produced. So, a cosmic ray getting into the atmosphere gives birth to a particle shower that can be detected. The atmosphere plays then a crucial role in the detection of cosmic rays, which can be studied from the secondary particles they produce.

Submitted by Andrea Santangelo & María Dolores
Rodríguez Frías for the JEM-EUSO Collaboration.


>> JEM-EUSO website


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