The Cherenkov Telescope Array (CTA) is the next-generation ground-based observatory for very-high-energy gamma-ray astronomy. An innovative 9.7 m aperture, dual-mirror Schwarzschild-Couder Telescope ...(SCT) design is a candidate design for CTA Medium-Sized Telescopes. A prototype SCT (pSCT) has been constructed at the Fred Lawrence Whipple Observatory in Arizona, USA. Its camera is currently partially instrumented with 1600 pixels covering a field of view of 2.7 degrees square. The small plate scale of the optical system allows densely packed silicon photomultipliers to be used, which combined with high-density trigger and waveform readout electronics enable the high-resolution camera. The camera's electronics are capable of imaging air shower development at a rate of one billion samples per second. We describe the commissioning and performance of the pSCT camera, including trigger and waveform readout performance, calibration, and absolute GPS time stamping. We also present the upgrade to the camera, which is currently underway. The upgrade will fully populate the focal plane, increasing the field of view to 8 degree diameter, and lower the front-end electronics noise, enabling a lower trigger threshold and improved reconstruction and background rejection.
For the first time in the history of ground-based \(\gamma\)-ray astronomy, the on-axis performance of the dual mirror, aspheric, aplanatic Schwarzschild-Couder optical system has been demonstrated ...in a \(9.7\)-m aperture imaging atmospheric Cherenkov telescope. The novel design of the prototype Schwarzschild-Couder Telescope (pSCT) is motivated by the need of the next-generation Cherenkov Telescope Array (CTA) observatory to have the ability to perform wide (\(\geq 8^{\circ}\)) field-of-view observations simultaneously with superior imaging of atmospheric cascades (resolution of \(0.067^{\circ}\) per pixel or better). The pSCT design, if implemented in the CTA installation, has the potential to improve significantly both the \(\gamma\)-ray angular resolution and the off-axis sensitivity of the observatory, reaching nearly the theoretical limit of the technique and thereby making a major impact on the CTA observatory sky survey programs, follow-up observations of multi-messenger transients with poorly known initial localization, as well as on the spatially resolved spectroscopic studies of extended \(\gamma\)-ray sources. This contribution reports on the initial alignment procedures and point-spread-function results for the challenging segmented aspheric primary and secondary mirrors of the pSCT.
The Schwarzschild-Couder Telescope (SCT) is a candidate technology for a medium-sized telescope within the Cherenkov Telescope Array, the next generation ground based observatory for very high energy ...gamma ray astronomy. The SCT uses a novel two-mirror design and is expected to yield improvements in field of view and image resolution compared to traditional Cherenkov telescopes based on single-mirror-dish optics. To match the improved optical resolution, challenging requirements of high channel count and density at low power consumption must be overcome by the camera. The prototype camera, currently commissioned and tested on the prototype SCT, has been developed based on millimeter scale SiPM pixels and a custom high density digitizer ASIC, TARGET, to provide 1600 pixels spanning a 2.7 degree field of view while being able to sample nanosecond photon pulses. It is mechanically designed to allow for an upgrade to 11,328 pixels covering a field of view of 8 degrees and demonstrating the full potential of the technology. The camera was installed on the telescope in 2018. We will present its design and performance including first light data.
The Cherenkov Telescope Array (CTA), with more than 100 telescopes, will be the largest ever ground-based gamma-ray observatory and is expected to greatly improve on both gamma-ray detection ...sensitivity and energy coverage compared to current-generation detectors. The 9.7-m Schwarzschild-Couder telescope (SCT) is one of the two candidates for the medium size telescope (MST) design for CTA. The novel aplanatic dual-mirror SCT design offers a wide field-of-view with a compact plate scale, allowing for a large number of camera pixels that improves the angular resolution and reduce the night sky background noise per pixel compared to the traditional single-mirror Davies-Cotton (DC) design of ground-based gamma-ray telescopes. The production, installation, and the alignment of the segmented aspherical mirrors are the main challenges for the realization of the SCT optical system. In this contribution, we report on the commissioning status, the alignment procedures, and initial alignment results during the initial commissioning phase of the optical system of the prototype SCT.
The Schwarzschild-Couder Telescope (SCT) is a proposal for the Medium Size Telescopes of the Cherenkov Telescope Array. Its concept is based on a two-mirror optical system designed to improve the ...telescope field of view and image resolution with respect to the single mirror Davies-Cotton solution. The SCT camera is planned to be instrumented with 177 photodetection modules, each composed of 64 Silicon Photomultiplier (SiPM) pixels. The third generation of \(6 x 6~mm^2\) high density NUV SiPMs (NUV-HD3) produced by Fondazione Bruno Kessler (FBK) in collaboration with INFN has been used to equip optical units to be integrated on the upgrade of the camera of the SCT prototype (pSCT). Each optical unit is composed of an array of 16 NUV-HD3 SiPMs coupled with the front-end electronics, which is designed for full-waveform nanosecond readout and digitization using the TARGET-7 ASIC. Several optical units have been assembled and tested in the laboratories of INFN and have been integrated on the camera of the pSCT telescope, that is currently operating at the Fred Lawrence Whipple Observatory. In this contribution we report on the development, assembly and calibration of the optical units that are currently taking data on the pSCT camera.
Recen% developed near W-photosensors are currently adopted in those applications where high sensitivity and good imaging capabilities are required, especially in fields such as astroparticle physics ...and medical imaging. An example of such applications is the camera of the Schwarzschild Couder Medium Size Telescope prototype (pSCT) which is in construction within the Cherenkov Telescope Array experiment. The camera consists of 177 photo-detection modules grouped into sectors of 25 modules, each based on matrixes of 64 6mm × 6mm pixels of Silicon Photomultipliers (SiPMs). Sensors produced by the Fondazione Bruno Kessler (FBK) in Italy are currently under investigation. Here we present a complete characterization of these highly sensitive near UV sensors, the assembly procedure and metrology results on several focal plane elements.
A new experimental apparatus for charged particle detection, named EXODET (EXOtic DETector) has been designed to be used in nuclear physics experiments involving RIBs (radioactive ion beams). Typical ...feature of RIBs presently available at the first-generation production facilities is the low beam intensity (10 5 -10 6 pps) therefore a large solid angle coverage and a high granularity are required to allow the reconstruction of the complete event kinematics. In this work are presented the main features of the EXODET apparatus, fulfilling the previous requirements, and the first experimental results.
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