Mini-EUSO Laser Test

Placed in the Russian Zvezda module of the International Space Station (ISS) in 2019, the Mini-EUSO (Extreme Universe Space Observatory) will measure earth's UV emission. Using a $1\ \text{Mhz}$ multi-anode photomultiplier camera and a $20\ \text{cm}$ diameter Fresnel Lens system, Mini-EUSO is sensitive to cosmic rays above $10^{21}\ \text{eV}$. The spatial resolution of Mini-EUSO is $6.11\ \text{km}$ and a temporal resolution $2.5\ \mu\text{s}$ with a field of view of $44^o$ in each direction.

A mobile high-power UV laser system will be used to test the expected energy threshold of Mini-EUSO. The laser emits pulsed $355\ \text{nm} $ UV light in the selectable energy range of $0.2$ to $90\ \text{mJ} $ to simulate the optical signature of an extensive air shower around $10^{18.5}$ to $10^{21}\ \text{eV}$.

Laser calibration methods and simulations are being prepared for the upcoming field campaign. The laser's energy calibration factor is stable within $5\ \% $. The characteristics of the laser system and Mini-EUSO have been implemented inside the JEM-EUSO OffLine software framework and can be used to simulate the detector response. The laser will not be aimed at the ISS, but instead aimed across the field of view of Mini-EUSO to produce a track.