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The sensor head of our CHAOS experiment contains various different detector types. One of them is the Bismuth-Germanium-Oxide (BGO) scintillator. We want to observe galactic cosmic rays. When the particles travel through the scintillator, photons are created. These mass-less, charge-less and super fast photons are the particle manifestation of light. They propagate through the BGO and are measured at two photodiodes glued to the outside surfaces of the BGO. But how exactly do they propagate through the scintillator? And what factors influence the signal yield at the photodiodes? Investigating this is the subject of my bachelor’s thesis, in which I wrote a Python-based program that simulates the photons’ path through the scintillator. Stay tuned for the results.

The CHAOS particle telescope will be able to differentiate between heavy particles and lighter particles in the Galactic Cosmic Rays (GCRs). The heavier particles are protons and different nuclei while electrons for example are among the lighter particles in the GCRs. To differentiate between those different kinds of high energetic particles the CHAOS telescope is going to use a Cherenkov detector in which particles who are moving faster than the speed of light in the medium are creating so called Cherenkov-radiation. At similar energies the heavier and the lighter particles in the GCRs have vastly different velocities. Therefore only the lighter particles who are moving fast enough will create Cherenkov-radiation in the medium.

In our Cherenkov detector, the material in which the Cherenkov-radiation is created will be aerogel. Aerogels are porous solid bodies whose volume can be made of up to 99.98% pores. Therefore aerogels are among the lightest materials available.

On 22 April, the eagerly awaited blocks of aerogel finally arrived in Kiel. The two custom made blocks from the aerogel factory in japan had to undergo strict inspections to check if they fulfill several quality criteria especially wether or not the deviations in dimension are of a tolerable amount. Because the aerogel is so dust sensitive and brittle the inspection had to be done in our dust free clean room. When we inspected the aerogel we had to undergo several steps to ensure that we don’t carry any dust or electrostatic charge into the clean room. Only in the clean room the aerogel’s packaging was opened and we first saw the sky blue color of the unpacked blocks. The 62mm * 62mm * 40 mm big blocks of aerogel weigh only 26.6 g. While inspecting, the aerogel blocks had to be handled with great caution not to damage or even scratch the material. Afterwards we decided that the aerogel blocks meet our requirements, the deviation in dimension are sufficiently small and. Now we can finally start experimenting with them and getting them ready for flight.