Markus Lauscher, Pedro Assis, Pedro Brogueira, Miguel Ferreira, Thomas Hebbeker, Luís Mendes, Christine Meurer, Lukas Middendorf, Tim Niggemann, Mário Pimenta, Johannes Schumacher, Maurice Stephan
A sophisticated technique to study ultra-high-energy cosmic rays is to measure the extensive air showers they
cause in the atmosphere. Upon impact on the atmosphere, the cosmic rays generate a cascade of secondary particles,
forming the air shower. The shower particles excite the atmospheric nitrogen molecules, which emit fluorescence
light in the near ultraviolet regime when de-exciting. Observation of the fluorescence light with suitable
optical telescopes allows a reconstruction of the energy and arrival direction of the initial particle. Due to their
high photon detection efficiency, silicon photomultipliers (SiPMs) promise to improve current photomultipliertube-
based fluorescence telescopes. We present the design and a full detector simulation of an SiPM-based
fluorescence telescope prototype, together with the expected telescope performance, and our first construction
steps. The simulation includes the air showers, the propagation of the fluorescence light through the atmosphere
and its detection by our refracting telescope. We have also developed a phenomenological SiPM model based on
measurements in our laboratories, simulating the electrical response. This model contains the photon detection
efficiency, its dependence on the incidence angle of light and the effects of thermal and correlated noise. We have
made a full performance analysis for the detection of air showers including the environmental background light.
Moreover, we will present the RandD in compact modular electronics using photon counting techniques for the
telescope readout.
A sophisticated method for the observation of ultra-high-energy cosmic rays (UHECRs) is the
fluorescence
detection technique of extensive air showers (EAS).
FAMOUS will be a small
fluorescence telescope, instrumented with silicon photomultipliers (SiPMs) as highly-sensitive
light detectors. In comparison to photomultiplier tubes, SiPMs promise to have a higher photon-detection-efficiency. An increase in sensitivity allows to detect more distant and lower energy showers which
will contribute to an enrichment of the current understanding of the development of EAS and the chemical
composition of UHECRs.
A sophisticated technique to measure extensive air showers initiated by ultra-high-energy cosmic rays is by
means of fluorescence telescopes. Secondary particles of the air shower excite nitrogen molecules of the atmosphere,
which emit fluorescence light when they de-excite. Due to their high photon detection efficiency (PDE)
silicon photomultipliers (SiPMs) promise to increase the sensitivity of todays fluorescence telescopes which use
photomultiplier tubes - for example the fluorescence detector of the Pierre Auger Observatory. On the other
hand drawbacks like a small sensitive area, a strong temperature dependency and a high noise rate have to be
managed.
We present plans for a prototype fluorescence telescope using SiPMs and a special light collecting optical system
of Winston cones to increase the sensitive area. In this context we made measurements of the relative PDE
of SiPMs depending on the incident angle of light. The results agree with calculations based on the Fresnel
equations. Furthermore, measurements of the brightness of the night sky are presented since this photon flux is
the main background to the fluorescence signals of the extensive air showers. To compensate the temperature
dependency of the SiPM, frontend electronics make use of temperature sensors and microcontrollers to directly
adjust the bias-voltage according to the thermal conditions. To reduce the noise rate we study the coincidence
of several SiPMs signals triggered by cosmic ray events. By summing up these signals the SiPMs will constitute
a single pixel of the fluorescence telescope.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.