A compact and light-weight refractive telescope for the observation of extensive air showers

Abstract

A : A general purpose instrument for imaging of Cherenkov light or fluorescence light emitted by extensive air showers is presented. Its refractive optics allows for a compact and lightweight design with a wide field-of-view of 12°. The optical system features a 0.5 m diameter Fresnel lens and a camera with 61 pixels composed of Winston cones and large-sized 6 × 6 mm 2 photo sensors. As photo sensors, semi conductor light sensors (SiPMs) are utilized. The camera provides a high photon detection efficiency together with robust operation. The enclosed optics permit operation in regions of harsh environmental conditions. The low price of the telescope allows the production of a large number of telescopes and the application of the instrument in various projects, such as FAMOUS for the Pierre Auger Observatory, HAWC's Eye for HAWC or IceAct for IceCube. In this paper the novel design of this telescope and first measurements are presented. K: Silicon photomultipliers (SiPMs), Ultra-high energy cosmic rays, refractive telescope, imaging air-Cherenkov telescope, fluorescence light

IceAct, small Imaging Air Cherenkov Telescopes for IceCube

“…The basic concept of the IceAct imaging air-Cherenkov telescopes is a compact and robust design, as outlined in [17], optimized for operation in extreme environments and cost efficiency. Thus, the telescope has enclosed optics with a large field-of-view.…”

“…IceAct Karen Andeen Figure 4: Top) Trigger rate (red) and smoothed rate (black) of the IceAct telescope during one day with a threshold of ≈ 54 PE per fixed 9 pixel-group (see [17] for further details). Bottom) Single pixel bias current with the maximum pixel current (blue) and the median pixel current (black).…”

HAWC’s Eye - Implementing hybrid detection at the HAWC Gamma-Ray Observatory

“…The HAWC's Eye telescope which was tested on site is a compact and light-weighted IACT [4]. It is composed by a Fresnel lens of 549.7 mm diameter that focuses light to the camera located in the focal plane with a distance of 502.1 mm from the lens.…”

Fluorescence light detection with the FAMOUS telescope

“…Each of them consists of an array of four SiPMs with 3x3 mm 2 area and a size cell of 100 µm. In [8] more details of the telescope are given.…”

“…Fresnel lens Carbon fiber tube 549.7 mm 502.1 mm In order to increase the detection area of the SiPMs, on top of each sensor a hollow Winston cone made of Aluminum has been placed [5,8]. It is a light collector whose design consists of a parabolic cone with a circular entrance of 6.7 mm radius, a circular exit of 3 mm radius and a lenght of 19.6 mm, providing a field of view (FOV) of 1.5 • each.…”