T. Kihm

HEROICA: an underground facility for the fast screening of germanium detectors

HEROICA (Hades Experimental Research Of Intrinsic Crystal Appliances) is an infrastructure to characterize germanium detectors and has been designed and constructed at the HADES Underground Research Laboratory, located in Mol (Belgium). Thanks to the 223 m overburden of clay and sand, the muon flux is lowered by four orders of magnitude. This natural shield minimizes the exposure of radio-pure germanium material to cosmic radiation resulting in a significant suppression of cosmogenic activation in the germanium detectors. The project has been strongly motivated by a special production of germanium detectors for the GERDA experiment. GERDA, currently collecting data at the Laboratori Nazionali del Gran Sasso of INFN, is searching for the neutrinoless double beta decay of 76Ge. In the near future, GERDA will increase its mass and sensitivity by adding new Broad Energy Germanium (BEGe) detectors. The production of the BEGe detectors is done at Canberra in Olen (Belgium), located about 30 km from the underground test site. Therefore, HADES is used both for storage of the crystals over night, during diode production, and for the characterization measurements. A full quality control chain has been setup and tested on the first seven prototype detectors delivered by the manufacturer at the beginning of 2012. The screening capabilities demonstrate that the installed setup fulfills a fast and complete set of measurements on the diodes and it can be seen as a general test facility for the fast screening of high purity germanium detectors. The results are of major importance for a future massive production and characterization chain of germanium diodes foreseen for a possible next generation 1-tonne double beta decay experiment with 76Ge.

A digital multi-channel spectroscopy system with 100 MHz flash ADC module for the GENIUS-TF and GENIUS projects

In this paper we present the first results of applying a digital processing technology in low-level gamma spectroscopy with HPGE detectors. An experimental gamma spectrometer using Flash ADC module is built and tested. The test system is now under development and shows major advantages over the traditional analog technologies. It will be installed for the GENIUS-TF and GENIUS projects in Gran-Sasso in early 2003.

FlashCam: A fully digital camera for CTA telescopes

The future Cherenkov Telescope Array (CTA) will consist of several tens of telescopes of different mirror sizes. CTA will provide next generation sensitivity to very high energy photons from few tens of GeV to > 100 TeV. Several focal plane instrumentation options are currently being evaluated inside the CTA consortium. In this paper, the current status of the FlashCam prototyping project is described. FlashCam is based on a fully digital camera readout concept and features a clean separation between photon detector plane and signal digitization/triggering electronics.

The Cosmic Ray Tracking (CRT) detector system

Abstract The Cosmic Ray Tracking (CRT) project represents a study on the use of tracking detectors of the time projection chamber type to detect secondary cosmic ray particles in extensive air showers. In reconstructing the arrival direction of the primary cosmic ray particles, the CRT detectors take advantage of the angular correlation of secondary particles with the cosmic rays leading to these air showers. In this paper, the detector hardware including the custom-designed electronics system is described in detail. A CRT detector module provides an active area of 2.5 m 2 and allows to measure track directions with a precision of 0.4°. It consists of two circular drift chambers of 1.8 m diameter with six sense wires each, and a 10cm thick iron plate between the two chambers. Each detector has a local electronics box with a readout, trigger, and monitoring system. The detectors can distinguish penetrating muons from other types of charged secondaries. A large detector array could be used to search for γ -ray point sources at energies above several TeV and for studies of the cosmic-ray composition. Ten detectors are in operation at the site of the HEGRA air shower array.

Performance Verification of the FlashCam Prototype Camera for the Cherenkov Telescope Array

Abstract The Cherenkov Telescope Array (CTA) is a future gamma-ray observatory that is planned to significantly improve upon the sensitivity and precision of the current generation of Cherenkov telescopes. The observatory will consist of several dozens of telescopes with different sizes and equipped with different types of cameras. Of these, the FlashCam camera system is the first to implement a fully digital signal processing chain which allows for a traceable, configurable trigger scheme and flexible signal reconstruction. As of autumn 2016, a prototype FlashCam camera for the medium-sized telescopes of CTA nears completion. First results of the ongoing system tests demonstrate that the signal chain and the readout system surpass CTA requirements. The stability of the system is shown using long-term temperature cycling.

A Trigger And Readout Scheme For Future Cherenkov Telescope Arrays

The next generation of ground‐based gamma‐ray observatories, such as e.g. CTA will consists of about 50–100 Telescopes, and cameras with in total ∼100000 to ∼200000 channels. The telescopes of the core array will cover and effective area of ∼1 km2 and will be possibly accompanied by a large “halo” of smaller telescopes spread over about 10 km2. In order to make maximum use of the stereoscopic approach, a very flexible inter‐telescope trigger scheme is needed which will allow to couple telescopes that located up to ∼1 km apart. At the same time, the development of a cost effective readout scheme for the camera signals exhibits a major technological challenge. Here we present ideas on a new asynchronous inter‐telescope trigger scheme, and a very cost‐effective, high‐bandwidth frontend to backend data transfer system, both based on standard Ethernet components and an Ethernet front‐end interface based on mass production standard FPGAs.

FlashCam: a fully-digital camera for the medium-sized telescopes of the Cherenkov Telescope Array

The FlashCam group is currently preparing photomultiplier-tube based cameras proposed for the medium-sized telescopes (MST) of the Cherenkov Telescope Array (CTA). The cameras are designed around the FlashCam readout concept which is the first fully-digital readout system for Cherenkov cameras, based on commercial FADCs and FPGAs as key components for the front-end electronics modules and a high performance camera server as back-end. This contribution describes the progress of the full-scale FlashCam camera prototype currently under construction, as well as performance results also obtained with earlier demonstrator setups. Plans towards the production and implementation of FlashCams on site are also briefly presented.

FlashCam: A camera concept and design for the Cherenkov Telescope Array CTA

G. PUHLHOFER, C. BAUER , A. BILAND , D. FLORIN , C. FOHR , A. GADOLA , R. GREDIG , G. HERMANN , J. HINTON , B. HUBER , C. KALKUHL, J. KASPEREK , E. KENDZIORRA , T. KIHM , J. KOZIOL, A. MANALAYSAY, P.J. RAJDA , T. SCHANZ , S. STEINER , U. STRAUMANN , C. TENZER, P. VOGLER, A. VOLLHARDT, Q. WEITZEL, R. WHITE, K. ZIETARA, FOR THE CTA CONSORTIUM 1 Max-Planck-Institut fur Kernphysik, P.O. Box 103980, D 69029 Heidelberg, Germany 2 ETH Zurich, Inst. for Particle Physics, Schafmattstr. 20, CH-8093 Zurich, Switzerland 3 Physik-Institut, Universitat Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland 4 Dept. of Physics and Astronomy, University of Leicester, Leicester, LE1 7RH, UK 5 Institut fur Astronomie und Astrophysik, Kepler Center for Astro and Particle Physics, Eberhard-Karls-Universitat, Sand 1, D 72076 Tubingen, Germany 6 Faculty of Electrical Engineering, Automatics, Computer Science and Electronics, AGH University of Science and Technology, Al. Mickiewicza 30, 30-059 Cracow, Poland 7 Jagiellonian University, ul. Orla 171, 30-244 Cracow, Poland 8 See http://www.cta-observatory.org/?q=node/342 for full author & affiliation list Gerd.Puehlhofer@astro.uni-tuebingen.de

FlashCam: a novel Cherenkov telescope camera with continuous signal digitization

The Cherenkov Telescope Array (CTA) will be the next generation ground-based observatory for cosmic gamma rays. The FlashCam camera for its mid-size telescope introduces a new concept, with a modest sampling rate of 250 MS/s, that enables a continuous digitization as well as event buffering and trigger processing using the same front-end FPGAs. The high performance Ethernet-based readout provides a dead-time free operation for event rates up to 30 kHz corresponding to a data rate of 2.0 GByte/s sent to the camera server. We present the camera design and the current status of the project.

Trigger performance verification of the FlashCam prototype camera

Abstract FlashCam is a camera proposed for the medium-sized telescopes of the Cherenkov Telescope Array (CTA). We compare camera trigger rates obtained from measurements with the camera prototype in the laboratory and Monte Carlo simulations, when scanning the parameter space of the fully-digital trigger logic and the intensity of a continuous light source mimicking the night sky background (NSB) during on-site operation. The comparisons of the measured data results to the Monte Carlo simulations are used to verify the FlashCam trigger logic and the expected trigger performance.