Search results for "Coin"
showing 10 items of 612 documents
The Cryogenic AntiCoincidence Detector Project for ATHENA+: An Overview Up to the Present Status
2014
ATHENA+ is a space mission proposal for the next ESA L2-L3 slot. One of the focal plane instruments is the X-ray integral field unit (X-IFU) working in the energy range 0.3–10 keV. It is a multi-array based on TES detectors aimed at characterizing faint or diffuse sources (e.g. WHIM or galaxy outskirt). The X-IFU will be able to achieve the required sensitivity if a low background is guaranteed. The studies performed by GEANT4 simulations depict a scenario where the use of an active anticoincidence (AC) is mandatory to reduce the background expected in L2 orbit down to the goal level of 0.005 cts cm $$^{-2}$$ s $$^{-1}$$ keV $$^{-1}$$ . This is possible using a cryogenic anticoincidence (…
First coincidences in pre-clinical Compton camera prototype for medical imaging
2003
Abstract Compton collimated imaging may improve the detection of gamma rays emitted by radioisotopes used in single photon emission computed tomography (SPECT). We present a crude prototype consisting of a single 500 μm thick, 256 pad silicon detector with pad size of 1.4×1.4 mm 2 , combined with a 15×15×1 cm 3 NaI scintillator crystal coupled to a set of 20 photo multipliers. Emphasis is placed on the performance of the silicon detector and the associated read-out electronics, which has so far proved to be the most challenging part of the set-up. Results were obtained using the VATAGP3, 128 channel low-noise self-triggering ASIC as the silicon detector's front-end. The noise distribution (…
A Ge(Li)Ge(Li) sum-peak (summing coincidence) spectrometer
1970
Abstract The sum-peak spectrometer (also called the integral-bias summing coincidence spectrometer) arrangement earlier developed with NaI(Tl) detectors is extended to Ge(Li) detectors. The integral-bias method in sorting sums of coincident pulse amplitudes is replaced by a set of pulse-height selection windows, which simply and more effectively aid in the analysis of sum-peak complexities associated with the symmetric linear summing procedure employed. A large part of the original information lost in summing of the pulse amplitudes can be retained by simultaneous sorting of the total spectrum into suitable subgroups. The arrangement represents in effect a real-time totalizing spectrometer …
Simultaneous recording of true and random coincidences using a two-parameter analyzer system
1971
Abstract A description is given of a simple fast coincidence method which allows the simultaneous recording of coincidence and random coincidence spectra. The method is based on the properties of a standard two-parameter pulse-height analyzer system, and no special electronics is required.
Multimode squeezing of frequency combs
2006
We have developed a full multimode theory of a synchronously pumped type-I optical parametric oscillator. We calculate the output quantum fluctuations of the device and find that, in the degenerate case (coincident signal and idler set of frequencies), significant squeezing is obtained when one approaches threshold from below for a set of well-defined ``supermodes,'' or frequency combs, consisting of a coherent linear superposition of signal modes of different frequencies which are resonant in the cavity.
High-resolution multichannel Time-to-Digital Converter core implemented in FPGA for ToF measurements in SiPM-PET
2013
In this contribution, Coincidence Resolving Time (CRT) results with the developed multichannel FPGA-TDC are showed as a function of different configurations for both, the sensor bias voltage and the digitizer threshold. The dependence of the CRT with the sensor matrix temperature, the amount of SiPM active area and the crystal type are also analyzed. Preliminary measurements carried out with a crystal array of 2 mm pixel size and 10 mm height have shown time resolutions for the entire 144 SiPM two-detectors ensemble as good as 800 ps.
Secondary electron flight times and tracks in the carbon foil time pick-up detector
2014
Carbon foil time pick-up detectors used in the time-of-flight measurements of MeV energy ions have been studied in connection to time-of-flight-energy spectrometer used for heavy ion elastic recoil detection analysis. In experimental coincident TOF-E data characteristic halos are observed around light element isobars, and the origin of these halos were studied. The experimental data indicated that these halos originate from single electron events occurring before the electron multiplication in the microchannel plate. By means of electron trajectory simulations, this halo effect is explained to originate from single electron, emitted from the carbon foil, hitting the non-active area of the m…
Fission fragment angular distributions in the capture reactions 50Ti, 56Fe + 208Pb
2008
The analysis of %-ray mult ip l ic i t ies measured I in coincidence with capture fission events in reactions of 26Mg through 54Cr, 58Fe, and 64Ni with 208pb in terms of Ko and~eff revealed1 that the resulting values of ~ /~e f f were rather independent of for a given system and, in a compound nucleus picture, were more in agreement with the 'shape of the non-rotating saddle than with the actually expected rotating saddle I f non-compound systenmhave to be considered these values of ~/J~ff__ shapes. suggested at least that the captured systems near the turning point from the inward radial motion to symmetric fragmentation had reached a remarkable compactness.
Mami Experimental Activity
1992
The Mainz Microtron MAMI is shortly described followed by a sketch of the three main experimental facilities: the Al collaboration realizing a 3-spectrometer set-up, the A2 collaboration realizing a photon tagger together with numerous dedicated detectors, and the A3 collaboration realizing a facility to use polarized electrons and polarized targets for the measurement of the electric form factor of the neutron G e,n. The physics program of the first round is outlined by listing all planned experiments.
Radiative Pion Photoproduction from the Proton and π + Meson Polarizabilities
1995
We study the possibility of investigating radiative pion photoproduction from the proton at the microtron MAMI-B with the aim to obtain an experimental information about the π + meson polarizabilities. It is shown that an exposition time of about 30 days will allow to determine the π + meson polarizability with quite high accuracy.