This session includes topics related to detector development, radiation modeling, pre-flight and space flight mission development for astrophysics and space science.
The Calibration of the Compton Spectrometer and Imager for the 2016 Balloon Campaign (#3558)
C. C. Sleator1, S. E. Boggs1, C. - L. Chiu1, C. A. Kierans1, A. Lowell1, J. A. Tomsick1, A. Zoglauer1, M. Amman2, H. - K. Chang3, C. - H. Tseng3, C. - Y. Yang3, P. Jean4, P. von Ballmoos4
1 UC Berkeley, Space Sciences Laboratory, Berkeley, California, United States of America
The Compton Spectrometer and Imager (COSI) is a balloon-borne soft gamma-ray (0.2-5 MeV) telescope desgined to study astrophysical sources such as gamma-ray bursts, positron annihilation, Galactic nucleosynthesis, and compact objects. COSI was launched from Wanaka, New Zealand in May 2016 and completed a successful 46-day flight on NASA’s new super pressure balloon. COSI employs a compact Compton telescope design utilizing 12 high-purity cross strip germanium detectors that measure the deposited energy and position of each interaction. From these measured values, we are able to reconstruct the source position on the sky, perform spectral analysis, and measure the degree of linear polarization of the incident photons. A well-calibrated detector is essential for this high level analysis, and we have implemented an energy and position calibration prior to the 2016 flight. By measuring the spectra of radioactive sources at known line energies, we determine the relation between pulse height and energy. We establish the 3D interaction position from the orthogonal strips and the depth in the detector, which is in turn determined by measuring the charge collection time difference between the anode and the cathode. We will discuss these detector calibrations and the instrument benchmarking done prior to the 2016 flight.
Keywords: Detectors, Calibration, Strips, Telescopes, Extraterrestrial measurements
Calocube: a new homogeneous calorimeter for high-energy cosmic rays detection in space (#3186)
G. Bigongiari1, 2
1 INFN, Sezione di Pisa, Pisa, Italy
Unambiguous measurements of the energy spectra and of the composition of cosmic rays up to the knee region, around 1 PeV, could provide important clues on their origin, acceleration mechanism, propagation and composition. Nowadays, due to the extremely low particle rates at these energies, spectral measurements in the knee region are mainly derived from data collected by ground-based detectors and are subject to the high uncertainties typical of indirect measurements, which rely on sophisticated modeling of the interaction of the primary particle with the atmosphere. A space experiment dedicated to measurements in this energy region has to achieve a balance between the requirements of lightness and compactness, with that of a large acceptance to cope with the low particle rates. To overcome this limitation an innovative cubic calorimeter is presented, which addresses these issues while limiting the mass and volume of the detector. The large acceptance needed is obtained by maximizing the number of entrance windows, while thanks to its homogeneity and high segmentation this new detector allows to achieve an excellent energy resolution and an enhanced separation power between hadrons and electrons. A prototype of the proposed detector, instrumented with CsI(Tl) cubic crystals, has already taken data with ion beams at CERN SPS. Its performance and perspective for future experiments in space are discussed.
Keywords: Cosmic Rays, calorimeter, CaloCube
APiX : a Geiger-mode avalanche digital sensor for charged particle detection (#2908)
P. S. Marrocchesi1, 2
1 University of Siena, Dpt. of Physical Sciences, Earth and Environment, Siena, Italy
The APiX sensor is a position-sensitive detector of ionizing radiation with an internal gain provided by its operation in avalanche mode. Its working principle is based on the on-chip integration of pairs of vertically-aligned pixels operated in coincidence to discriminate between particle events and dark counts. This novel concept allows to reduce the material budget and the power consumption in the presence of a high granularity and fast timing response. A proof-of-principle prototype, implemented under 150 nm standard CMOS, was first characterized and then tested with a high energy particle beam at CERN SPS, featuring a reduction of the dark-count rate (DCR) at room temperature from ~100 kHz/mm2 to about 24 Hz/mm2 and a particle detection efficiency limited only by the geometric factor. Potential applications include high spatial resolution tracking in high-energy experiments, radiation monitoring in space and radiation imaging in nuclear medicine. A small hand-held demonstrator is under construction for radio-guided surgery.
Keywords: particle detectors; avalanche detectors;
Design of a Compact Neutron Spectrometer Using the CLYC Scintillator (#1703)
Q. Wang1, 3, Y. Yang2, X. Tuo1, 3, C. Deng3, 4, H. Li4
1 Chengdu University of Technology, College of Nuclear Technology and Automation Engineering, Chengdu, China
Astronauts and spacecraft are exposed to space radiation from a variety of sources, including cosmic rays, cosmic-ray-induced neutrons and gamma rays. To determine the neutron dose to astronauts and spacecraft, an onboard neutron spectrometer with small size and low consumption design is required. The time-of-flight spectrometer and the moderation spectrometer are rejected for its long flight path and for its heavy-mass moderators, respectively. The organic scintillators have the morbid response matrix to reconstruct neutron spectrum as the responses to neutrons in different energies are highly similar. This paper present a new design of compact neutron spectrometer using the newly developed CLYC (Cs2LiYCl6: Ce) scintillator which is sensitive to both thermal neutrons and fast neutrons. An anti-coincidence plastic scintillator is used to reject the incident charged particle events, and the Pulse Shape Discrimination (PSD) ability of CLYC scintillator was utilized to reject gamma events. This compact neutron spectrometer uses the response matrix of monoenergetic neutrons ranging from thermal to 100 MeV and the response to incident neutrons to determine the neutron spectrum with the IRLS algorithm. The work is verified by the simulation results of Geant4.10.02 code, it shows that the constructed neutron spectrum consistent well with the incident spectrum.
Keywords: Compact Neutron Spectrometer, Neutron Energy Measurement, Cosmic-ray-induced Neutron, CLYC
Preparing for the Advanced Scintillator Compton Telescope (ASCOT) Balloon Flight (#2112)
P. F. Bloser1, T. Sharma1, J. S. Legere1, C. M. Bancroft1, M. L. McConnell1, J. M. Ryan1, A. M. Wright1
1 University of New Hampshire, Space Science Center, Durham, New Hampshire, United States of America
We describe our ongoing work to develop a new medium-energy gamma-ray Compton telescope using advanced scintillator materials combined with silicon photomultiplier readouts and fly it on a scientific balloon. There is a need in high-energy astronomy for a medium-energy gamma-ray mission covering the energy range from approximately 0.4 - 20 MeV to follow the success of the COMPTEL instrument on CGRO. We believe that directly building on the legacy of COMPTEL, using relatively robust, low-cost, off-the-shelf technologies, is the most promising path for such a mission. Fortunately, high-performance scintillators, such as Cerium Bromide (CeBr3) and p-terphenyl, and compact readout devices, such as silicon photomultipliers (SiPMs), are already commercially available and capable of meeting this need. We are now constructing an Advanced Scintillator Compton Telescope (ASCOT) with SiPM readout, with the goal of imaging the Crab Nebula at MeV energies from a high-altitude balloon flight. We expect a ~6-sigma detection in the 0.2 - 2 MeV energy band in a single transit. We present calibration results of the detector modules and full instrument, and updated simulations of the balloon payload sensitivity. If successful, this project will demonstrate that the energy, timing, and position resolution of this technology are sufficient to achieve an order of magnitude improvement in sensitivity in the medium-energy gamma-ray band, were it to be applied to a ~1 cubic meter instrument on a long-duration balloon or Explorer platform.
Keywords: Gamma rays; Astronomy; Compton telescope; scintillators; silicon photomultipliers
The EUSO-SPB mission: status and results. (#2470)
F. S. Cafagna1
1 INFN Sezione di Bari, Bari, Italy
The EUSO mission, on board of the International Space Station (ISS), has the primary scientific objective of doing astronomy and astrophysics detecting extreme energy cosmic rays (EECRs), above 3x10^19eV. This Extreme Universe Space Observatory (EUSO), will be the first space mission to be devoted to the study of this extreme energy range with the aim of extending the knowledge on sources, spectra and composition of cosmic rays in this energy range. This mission is a collaborative effort of about 353 Researchers of 89 Institutions, from 16 Countries.
The instrument has been designed to detect the UV photons emitted in the shower produced by the EECR interaction with the atmosphere and reconstruct the arrival direction, the energy and, possibly, the nature of the EECR. This will be possible thanks to a telescope looking downward, from the ISS into the night sky, composed by an optical module that focuses the UV photons onto a focal surface, housing a matrix of multi anode photomultipliers.
An infrared camera and a LIDAR will monitor the atmosphere in the telescope field of view, while an onboard and ground base systems will calibrate it.
The EUSO-SPB mission exploits the EUSO observatory on a super pressure balloon. This pathfinder will circle the southern hemisphere at an altitude of about 33km, potentially floating for duration that may reach 100 days. The instrument has been launched on the 24th of April, from the NASA’s CSBF (Columbia Scientific Balloon Facility) base in Wanaka, New Zeeland. At the time of writing, the instrument is taking data at the float altitude and started to transmit data to ground for first analysis.
Besides the description or the detector, details will be given on the first results along with plans for EUSO mission.
Keywords: Balloon borne detector, Cosmic Rays, Photon detector