The high flux proton component observed by AMS below the geomagnetic cutoff can be well accounted for by assuming these particles to be secondaries originating from the interaction of cosmic ray ...protons with the atmosphere. Simulation results are reported.
A readout method based on fast waveform digitalization is proposed which improves the performance of large multiwire proportional chambers (MWPCs) with delay-line readout. Atmospheric muon detection ...data are presented, obtained with a 1 mtimes1 m, 200 wire, MWPC and two plastic scintillators, having the same sensitive area, used for muon identification purposes. The performance of two alternative data acquisition configurations is compared: the standard one, based on analog constant fraction discriminators (CFDs), and one using 5 GS/s waveform digitizers in which a CFD-like analysis is performed offline. The latter is shown to provide better, and more uniform, space resolution, allowing to correct position-dependent rise-time variations across the detector. The new technique is applicable to low count-rate applications, such as muon attenuation measurements in large matter volumes
In-beam tests of the AMS RICH prototype with 20 A GeV/c secondary ions Baret, B.; Aguayo, P.; Benitez, M.A. ...
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment,
06/2004, Letnik:
525
Conference Proceeding
The critical behavior for the light nuclei with A∼36 has been investigated experimentally by the NIMROD multi-detectors. The wide variety of observables indicate the critical point has been reached ...in the disassembly of hot nuclei at an excitation energy of 5.6±0.5 MeV/u.
In-beam aerogel light yield characterization for the AMS RICH detector Aguilar-Benitez, M.; Arruda, L.; Barao, F. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
03/2010, Letnik:
614, Številka:
2
Journal Article
Recenzirano
The ring imaging Cherenkov (RICH) detector of the AMS-02 spectrometer provides a very precise measurement of the electric charge and velocity. The RICH detector is composed of a conical reflector ...ended on top by a dual radiator plane made of sodium fluoride and aerogel, and at the bottom by a detector plane made of pixelized photomultipliers. The vast majority of the events (
∼
90
%
) that are collected in the RICH cross the aerogel radiator. Therefore, the choice and characterization of the aerogel radiator is essential for reaching the design goals. A prototype of the RICH detector was built for both concept proof and testing of the different elements. Beam tests with the RICH prototype and using several aerogel radiator samples were performed at CERN in 2002 and 2003. This note summarizes the method used and the results obtained for the light yield of different aerogel samples.
The Cosmic Ray Energetics and Mass experiment at the International Space Station (ISS-CREAM) is developed for studying the origin, acceleration and propagation mechanism of high energy cosmic rays. ...The Top and Bottom Counting Detectors (TCD/BCD), sub-detectors of the ISS-CREAM instrument, are developed for electron/γ-ray physics. The TCD/BCD help distinguish electrons from protons by comparing the hit and shower width distributions for electrons and protons. The e/p separation capability of the TCD/BCD is studied by using the GEANT3 simulation package, and optimal parameters for the e/p separation are obtained.
Calorimetric and coalescence techniques have been employed to probe equilibration for hot nuclei produced in heavy-ion collisions of 35 to 55 MeV/nucleon projectiles with medium mass targets. ...Entrance channel mass asymmetries and energies were selected so that very hot composite nuclei of similar mass and excitation would remain after early stage preequilibrium particle emission. Intercomparison of the properties and deexcitation patterns for these different systems provides evidence for the production of hot nuclei with decay patterns relatively independent of the specific entrance channel.
The remarkable non-linear response of a Si p–i–n detector to relatively low-
Z (<26) ions recently reported by Whitlow and Zhang Nucl. Instr. and Meth. B 190 (2002) 375 is interpreted as ...charge-collection inefficiencies associated to the recombination occurring in high energy density regions near the particle track. Model calculations taking into account the geometry of the resulting charge-carrier distribution are shown to closely reproduce the data, reducing the calibration exercise from their proposed four parameters per
Z, to just three overall quantities, which have a simple physical interpretation.
A new approach to deal with non-linearities in Si detector response Menchaca-Rocha, A.; Cabrera, J.I.; Alfaro, R. ...
Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms,
07/2003, Letnik:
207, Številka:
3
Journal Article
Recenzirano
A model is proposed to understand the non-linear response of Si detectors to high
Z particles, which are responsible for the pulse height defect (PHD). In this phenomenon, inefficient charge ...collection due to charge carrier recombination is related to high energy density regions in the vicinity of the particle track, while contributions from non-ionizing atomic collisions are also estimated from the radial distribution of scattered lattice ions. These model calculations successfully reproduce published PHD data, while predicting unexpected effects in silicon-based semiconductor detection of high (relativistic) energy heavy ions. This is used to explain what seemed as intriguing features of silicon-tracker data from the Alpha Magnetic Spectrometer space project. The present model is proposed to obtain reliable ion energy measurements using silicon detectors.
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