► 16-channel, GSa/s digitizer chip TARGET. ► Designed for imaging atmospheric Cherenkov telescopes for very-high-energy gamma-ray astronomy. ► Measured chip performance details. ► A prototype camera ...module is described. ► The next-generation chip, TARGET 2, is described.
The next-generation very-high-energy (VHE) gamma-ray observatory, the Cherenkov Telescope Array, will feature dozens of imaging atmospheric Cherenkov telescopes (IACTs), each with thousands of pixels of photo-sensors. To be affordable and reliable, reading out such an array of up to a million channels requires event recording technology that is highly integrated and modular, with a low cost per channel. We present the design and performance of a chip targeted to this application: the TeV Array Readout with GSa/s sampling and Event Trigger (TARGET). This application-specific integrated circuit (ASIC) has 16 parallel input channels, a 4096-sample buffer for each channel, adjustable input termination, self-trigger functionality, and tight window-selected readout. We report the performance of the first-generation version of this chip (TARGET 1) in terms of sampling frequency, power consumption, dynamic range, current-mode gain, analog bandwidth, and cross talk. The large number of channels per chip allows a low cost per channel ($10 to $20 including front-end and back-end electronics but not including photosensors) to be achieved with a TARGET-based IACT readout system. In addition to basic performance parameters of the TARGET 1 chip, we present a camera module prototype as well as a second-generation chip (TARGET 2), both of which have now been produced.
Future detectors for high luminosity particle identification and ultra high energy neutrino observation would benefit from a digitizer capable of recording sensor signals with high analog bandwidth ...and large record depth, in a cost-effective, compact and low-power way.
A first version of the buffered large analog bandwidth (BLAB1) ASIC has been designed based upon the lessons learned from the development of the large analog bandwidth recorder and digitizer with Ordered Readout (LABRADOR) ASIC. While this LABRADOR ASIC has been very successful and forms the basis of a generation of new, large-scale radio neutrino detectors, its limited sampling depth is a major drawback. A prototype has been designed and fabricated with 64
k deep sampling at multi-GSa/s operation. We present test results and directions for future evolution of this sampling technique.
We describe herein a measurement of the Antarctic surface “roughness” performed by the balloon‐borne ANITA (Antarctic Impulsive Transient Antenna) experiment. Originally purposed for cosmic ray ...astrophysics, the radio frequency (RF) receiver ANITA gondola, from its 38 km altitude vantage point, can scan a disk of snow surface 600 km in radius. The primary purpose of ANITA is to detect RF emissions from cosmic rays incident on Antarctica, such as neutrinos which penetrate through the atmosphere and interact within the ice, resulting in signal directed upward which then refracts at the ice‐air interface and up and out to ANITA, or high‐energy nuclei (most likely irons or protons), which interact in the upper atmosphere (at altitudes below ANITA) and produce a spray of down‐coming RF which reflects off the snow surface and back up to the gondola. The energy of such high‐energy nuclei can be inferred from the observed reflected signal only if the surface reflectivity is known. We describe herein an attempt to quantify the Antarctic surface reflectivity, using the Sun as a constant, unpolarized RF source. We find that the reflectivity of the surface generally follows the expectations from the Fresnel equations, lending support to the use of those equations to give an overall correction factor to calculate cosmic ray energies for all locations in Antarctica. The analysis described below is based on ANITA‐II data. After launching from McMurdo Station in December 2008, ANITA‐II was aloft for a period of 31 days with a typical instantaneous duty cycle exceeding 95%.
Key Points
Solar radio radiation is used to determine Antarctic albedo
Reflection coefficients agree with Fresnel predictions at high incidence angles
Reflection coefficients are lower than expected at glancing incidence angles
Super B factories that will further probe the flavor sector of the Standard Model and physics beyond will demand excellent charged particle identification (PID), particularly K/π separation, for ...momenta up to 4GeV/c, as well as the ability to operate under beam backgrounds significantly higher than current B factory experiments. We describe an Imaging Time-of-Propagation (iTOP) detector which shows significant potential to meet these requirements. Photons emitted from charged particle interactions in a Cherenkov radiator bar are internally reflected to the end of the bar, where they are collected on a compact image plane using photodetectors with fine spatial segmentation in two dimensions. Precision measurements of photon arrival time are used to enhance the two dimensional imaging, allowing the system to provide excellent PID capabilities within a reduced detector envelope. Results of the ongoing optimization of the geometric and physical properties of such a detector are presented, as well as simulated PID performance. Validation of simulations is being performed using a prototype in a cosmic ray test stand at the University of Hawaii.
The focusing DIRC with waveform digitizing electronics Ruckman, L.L.; Nishimura, K.; Varner, G.S. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
11/2010, Letnik:
623, Številka:
1
Journal Article
Recenzirano
We have tested a novel Cherenkov imaging detector called the Focusing DIRC (FDIRC) with waveform digitizing electronics. The prototype's concept is based on the BaBar DIRC with several important ...improvements: (a) much faster, pixelated photon detectors, (b) a mirror that makes the photon detector smaller and less sensitive to background in future applications, and (c) electronics capable of measuring single photon resolution to σ≈150ps, which allows for correction due to chromatic error. In this test, the prototype has been instrumented with seven Hamamatsu H-8500 MaPMTs. Waveforms from ∼450 pixels are digitized with waveform sampling electronics based on the BLAB2 ASIC, operating at a sampling speed of ∼2.5GSa/s. This version of the FDIRC prototype was tested in a large cosmic ray telescope providing muon tracks with ∼1mrad angular resolution and a muon momentum cutoff of ≥1.6GeV/c.
We set the first limits on the ultra-high energy (UHE) neutrino fluence at energies greater than 109 GeV from gamma-ray bursts (GRBs) based on data from the second flight of the Antarctic Impulsive ...Transient Antenna (ANITA). During the 31 day flight of ANITA-II, 26 GRBs were recorded by Swift or Fermi. Of these, we analyzed the 12 GRBs which occurred during quiet periods when the payload was away from anthropogenic activity. In a blind analysis, we observe 0 events on a total background of 0.0044 events in the combined prompt window for all 12 low-background bursts. We also observe 0 events from the remaining 14 bursts. We place a 90% confidence level limit on the E --4 prompt neutrino fluence between 108 GeV < E < 1012 GeV of E 4 Delta *Q = 2.5 X 1017 GeV3 cm--2 from GRB090107A. This is the first reported limit on the UHE neutrino fluence from GRBs above 109 GeV, and the strongest limit above 108 GeV.
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