Prototype of the SST-1M Telescope Structure for the Cherenkov Telescope Array

A single-mirror small-size (SST-1M) Davies-Cotton telescope with a dish diameter of 4 m has been built by a consortium of Polish and Swiss institutions as a prototype for one of the proposed small-size telescopes for the southern observatory of the Cherenkov Telescope Array (CTA). The design represents a very simple, reliable, and cheap solution. The mechanical structure prototype with its drive system is now being tested at the Institute of Nuclear Physics PAS in Krakow. Here we present the design of the prototype and results of the performance tests of the structure and the drive and control system.Comment: In Proceedings of the 34th International Cosmic Ray Conference (ICRC2015), The Hague, The Netherlands. All CTA contributions at arXiv:1508.0589

Using muon rings for the optical throughput calibration of the SST-1M prototype for the Cherenkov Telescope Array

Imaging Atmospheric Cherenkov Telescopes (IACTs) are ground-based instruments devoted to the study of very high energy gamma-rays coming from space. The detection technique consists of observing images created by the Cherenkov light emitted when gamma rays, or more generally cosmic rays, propagate through the atmosphere. While in the case of protons or gamma-rays the images present a filled and more or less elongated shape, energetic muons penetrating the atmosphere are visualised as characteristic circular rings or arcs. A relatively simple analysis of the ring images allows the reconstruction of all the relevant parameters of the detected muons, such as the energy, the impact parameter, and the incoming direction, with the final aim to use them to calibrate the total optical throughput of the given IACT telescope. We present the results of preliminary studies on the use of images created by muons as optical throughput calibrators of the single mirror small size telescope prototype SST-1M proposed for the Cherenkov Telescope Array.Comment: In Proceedings of the 34th International Cosmic Ray Conference (ICRC2015), The Hague, The Netherlands. All CTA contributions at arXiv:1508.0589

DigiCam - Fully Digital Compact Read-out and Trigger Electronics for the SST-1M Telescope proposed for the Cherenkov Telescope Array

The SST-1M is one of three prototype small-sized telescope designs proposed for the Cherenkov Telescope Array, and is built by a consortium of Polish and Swiss institutions. The SST-1M will operate with DigiCam - an innovative, compact camera with fully digital read-out and trigger electronics. A high level of integration will be achieved by massively deploying state-of-the-art multi-gigabit transmission channels, beginning from the ADC flash converters, through the internal data and trigger signals transmission over backplanes and cables, to the camera's server link. Such an approach makes it possible to design the camera to fit the size and weight requirements of the SST-1M exactly, and provide low power consumption, high reliability and long lifetime. The structure of the digital electronics will be presented, along with main physical building blocks and the internal architecture of FPGA functional subsystems.Comment: In Proceedings of the 34th International Cosmic Ray Conference (ICRC2015), The Hague, The Netherlands. All CTA contributions at arXiv:1508.0589

Products from decomposition of organic compounds : example of a mass grave in Niepołomice near Cracow

W celu oceny zjawisk dekompozycji masowego grobu w Puszczy Niepołomickiej przeprowadzono badania mineralogiczno-petrograficzne podłoża. Wykonano je za pomocą mikroskopów polaryzacyjnego oraz skaningowego wraz z przystawką elektronową EDS pozwalającą wykonać półilościowe analizy chemiczne. Ponadto zbadano koncentrację występujących w próbkach pierwiastków: Na, K, Mg, Ca, Cr, Mn, Fe, Ni, Cu, Zn, Cd, Al, Si, Pb, N, P, S, F, Cl i I za pomocą absorpcyjnej spektroskopii atomowej AAS. Badania prowadzono w miejscu pochówku, w jego bezpośrednim otoczeniu oraz w profilu porównawczym, odległym o około 300 m od masowego grobu. W pracy tej wykazano, że pierwiastki uwolnione podczas dekompozycji pozostają w środowisku masowego grobu, np. w wyniku sorpcji fosforu, wyznacznika procesu dekompozycji, na tleno-wodorotlenkach Fe. Na głębokości miejsca pochówku, wykazano wielokrotnie wyższe zawartości wielu pierwiastków: P, Cl, F, Na, Zn, Cu, S, N, K, Ca i I, których ilość znacznie wolniej maleje wraz z głębokością w porównaniu z profilem porównawczym. Badania te jednoznacznie wskazują na konieczność stosowania barier ochronnych wokół współczesnych cmentarzy w celu zabezpieczenia środowiska, a zwłaszcza wód gruntowych, przed ich niekorzystnym wpływem.In order to evaluate decomposition phenomena of the mass grave from Puszcza Niepołomicka (a forest near Niepołomice), mineral-petrography soil research was conducted by use of polarizing and scanning microscop equipped with EDS electron attachment allowing to perform semi--quantitive chemical analysis. Also, concentration of elements occurring in the samples was measured: Na, K, Mg, Ca, Cr, Mn, Fe, Ni, Cu, Zn, Cd, Al, Si, Pb, N, P, S, F, Cl and I by use of atomic absorption spectroscopy AAS. Research was conducted in the place of burial, its closest vicinity and in the comparative profile situated about 300 m away from the mass grave. In this work it was proved that elements released during the decomposition process remain in the mass grave environment, e.g. as a result of phosphorus sorption, decomposition process determinant, on oxide - Fe hydroxides. At the depth of the burial, significantly higher contents of many elements were analysed: P, Cl, F, Na, Zn, Cu, S, N, K, Ca and I, which drops significantly with the depth when compared to the comparison profile. This research unequivocally states that there is a necessity to use protection barriers around modern graveyards in order to protect the environment, especially groundwaters, from their adverse influence

DigiCam : fully digital compact camera for SST-1M telescope

The single mirror Small Size Telescopes (SST-1M), being built by a sub-consortium of Polish and Swiss Institutions of the CTA Consortium, will be equipped with a fully digital camera with a compact photodetector plane based on silicon photomultipliers. The internal trigger signal transmission overhead will be kept at low level by introducing a high level of integration. It will be achieved by massively deploying state-of-the-art multi-gigabit transceivers, beginning from the ADC flash converters, through the internal data and trigger signals transmission over backplanes and cables, to the camera's server 10Gb/s Ethernet links. Such approach will allow fitting the size and weight of the camera exactly to the SST-1M needs, still retaining the flexibility of a fully digital design. Such solution has low power consumption, high reliability and long lifetime. The concept of the camera will be described, along with some construction details and performance results

Performance of the small size telescope sub-array of the Cherenkov Telescope Array observatory

The southern part of the Cherenkov Telescope Array (CTA) observatory will consist of at least three types of telescopes: large size, medium size and small size telescopes. Massive Monte Carlo simulations have been performed using the European Grid Infrastructure to analyze the performance of this array. We present the results of these simulations for a sub-array of small size telescopes of the Davies-Cotton type. Such a telescope, called SST-1M, is currently being proposed for the CTA observatory by a group of Polish and Swiss institutions. SST-1M will have a mirror of 4m diameter and it will be equipped with a fully digital camera based on silicon photodetectors. We present the analysis of the sub-array sensitivity, angular resolution, and energy resolution to demonstrate the fulfillment of the requirements of the CTA Consortium. To verify the results obtained in numerical simulations a construction of a mini array of five SST-1M telescopes is planned. We also present the performance of such a mini array and discuss the prospects of its scientific program

Camera calibration strategy of the SST-1M prototype of the Cherenokov Telescope Array

The SST-1M telescope is one of the prototypes under construction proposed to be part of the future Cherenkov Telescope Array. It uses a standard Davis-Cotton design for the optics and telescope structure, with a dish diameter of 4 meters and a large field-of-view of 9 degrees. The innovative camera design is composed of a photo-detection plane with 1296 pixels including entrance window, light concentrators, Silicon Photomultipliers (SiPMs), and pre-amplifier stages together with a fully digital readout and trigger electronics, DigiCam. In this contribution we give a general description of the analysis chain designed for the SST-1M prototype. In particular we focus on the calibration strategy used to convert the SiPM signals registered by DigiCam to the quantities needed for Cherenkov image analysis. The calibration is based on an online feedback system to stabilize the gain of the SiPMs, as well as dedicated events (dark count, pedestal, and light flasher events) to be taken during the normal operation of the prototype.Comment: In Proceedings of the 34th International Cosmic Ray Conference (ICRC2015), The Hague, The Netherlands. All CTA contributions at arXiv:1508.0589