COMPARING CORRELATED PARAMETER ESTIMATES FOR NONLINEAR PET MODEL

The nonlinear PET model based on Newton\u27s law of cooling can be used to estimate body temperature in cattle, T b challenged by hot cyclic chamber temperatures, T a . The PET model has four biologically meaningful parameters: K, the thermal constant; Δ, the difference between T b and adjusted T a ; Υ the proportion of variation in T b comparable to variation in Ta ; T bini, the initial body temperature. The two parameters Y and Δ are highly correlated in the current version of the model. This study looks at other ways to parameterize the PET model in an effort to reduce the correlation between parameters and improve nonlinear behaviors, such as parameter-effects curvature, bias, excess variance and skewness

Detection of ultra-high energy cosmic ray showers with a single-pixel fluorescence telescope

We present a concept for large-area, low-cost detection of ultra-high energy cosmic rays (UHECRs) with a Fluorescence detector Array of Single-pixel Telescopes (FAST), addressing the requirements for the next generation of UHECR experiments. In the FAST design, a large field of view is covered by a few pixels at the focal plane of a mirror or Fresnel lens. We report first results of a FAST prototype installed at the Telescope Array site, consisting of a single 200 mm photomultiplier tube at the focal plane of a 1 m$^2$ Fresnel lens system taken from the prototype of the JEM-EUSO experiment. The FAST prototype took data for 19 nights, demonstrating remarkable operational stability. We detected laser shots at distances of several kilometres as well as 16 highly significant UHECR shower candidates.Comment: Accepted for publication in Astroparticle Physic

The Central Laser Facility at the Pierre Auger Observatory

The Central Laser Facility is located near the middle of the Pierre Auger Observatory in Argentina. It features a UV laser and optics that direct a beam of calibrated pulsed light into the sky. Light scattered from this beam produces tracks in the Auger optical detectors which normally record nitrogen fluorescence tracks from cosmic ray air showers. The Central Laser Facility provides a "test beam" to investigate properties of the atmosphere and the fluorescence detectors. The laser can send light via optical fiber simultaneously to the nearest surface detector tank for hybrid timing analyses. We describe the facility and show some examples of its many uses.Comment: 4 pages, 5 figures, submitted to 29th ICRC Pune Indi

Interpreting ~1 Hz magnetic compressional waves in Mercury's inner magnetosphere in terms of propagating ion‐Bernstein waves

We show that ~1 Hz magnetic compressional waves observed in Mercury's inner magnetosphere could be interpreted as ion‐Bernstein waves in a moderate proton beta ~0.1 plasma. An observation of a proton distribution with a large planetary loss cone is presented, and we show that this type of distribution is highly unstable to the generation of ion‐Bernstein waves with low magnetic compression. Ray tracing shows that as these waves propagate back and forth about the magnetic equator; they cycle between a state of low and high magnetic compression. The group velocity decreases during the high‐compression state leading to a pileup of compressional wave energy, which could explain the observed dominance of the highly compressional waves. This bimodal nature is due to the complexity of the index of refraction surface in a warm plasma whose upper branch has high growth rate with low compression, and its lower branch has low growth/damping rate with strong compression. Two different cycles are found: one where the compression maximum occurs at the magnetic equator and one where the compression maximum straddles the magnetic equator. The later cycle could explain observations where the maximum in compression straddles the equator. Ray tracing shows that this mode is confined within ±12° magnetic latitude which can account for the bulk of the observations. We show that the Doppler shift can account for the difference between the observed and model wave frequency, if the wave vector direction is in opposition to the plasma flow direction. We note that the Wentzel‐Kramers‐Brillouin approximation breaks down during the pileup of compressional energy and that a study involving full wave solutions is required.Key PointsThe ion‐Bernstein (IB) mode is highly unstable to proton loss cones at MercuryThe IB mode can become highly compressional as it propagatesRay tracing of the IB mode predicts compression peaking the off equatorPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/112180/1/jgra51808.pd

Performance of a small size telescope (SST-1M) camera for gamma-ray astronomy with the Cherenkov Telescope Array

The foreseen implementations of the Small Size Telescopes (SST) in CTA will provide unique insights into the highest energy gamma rays offering fundamental means to discover and under- stand the sources populating the Galaxy and our local neighborhood. Aiming at such a goal, the SST-1M is one of the three different implementations that are being prototyped and tested for CTA. SST-1M is a Davies-Cotton single mirror telescope equipped with a unique camera technology based on SiPMs with demonstrated advantages over classical photomultipliers in terms of duty-cycle. In this contribution, we describe the telescope components, the camera, and the trigger and readout system. The results of the commissioning of the camera using a dedicated test setup are then presented. The performances of the camera first prototype in terms of expected trigger rates and trigger efficiencies for different night-sky background conditions are presented, and the camera response is compared to end-to-end simulations.Comment: All CTA contributions at arXiv:1709.0348

Development of a strategy for calibrating the novel SiPM camera of the SST-1M telescope proposed for the Cherenkov Telescope Array

CTA will comprise a sub-array of up to 70 small size telescopes (SSTs) at the southern array. The SST-1M project, a 4 m-diameter Davies Cotton telescope with 9 degrees FoV and a 1296 pixels SiPM camera, is designed to meet the requirements of the next generation ground based gamma-ray observatory CTA in the energy range above 3 TeV. Silicon photomultipliers (SiPM) cameras of gamma-ray telescopes can achieve good performance even during high night sky background conditions. Defining a fully automated calibration strategy of SiPM cameras is of great importance for large scale production validation and online calibration. The SST-1M sub-consortium developed a software compatible with CTA pipeline software (CTApipe). The calibration of the SST-1M camera is based on the Camera Test Setup (CTS), a set of LED boards mounted in front of the camera. The CTS LEDs are operated in pulsed or continuous mode to emulate signal and night sky background respectively. Continuous and pulsed light data analysis allows us to extract single pixel calibration parameters to be used during CTA operation.Comment: All CTA contributions at arXiv:1709.0348