ABSTRACT Precision measurements of the electron component of cosmic radiation provide important information about the origin and propagation of cosmic rays in the Galaxy not accessible from the study ...of cosmic-ray nuclear components due to their differing diffusion and energy-loss processes. However, when measured near Earth, the effects of propagation and modulation of Galactic cosmic rays in the heliosphere, particularly significant for energies up to at least 30 GeV, must be properly taken into account. In this paper the electron (e−) spectra measured by the Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics down to 70 MeV from 2006 July to 2009 December over six-month time intervals are presented. Fluxes are compared with a state-of-the-art three-dimensional model of solar modulation that reproduces the observations remarkably well.
Pixelated resistive Micromegas detector for high-rate environment Alviggi, M.; Camerlingo, M.T.; Pietra, M. Della ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
10/2022, Letnik:
1041
Journal Article
Recenzirano
The R&D work reported in this paper has been devoted to the production and test of pixelated resistive micromegas detectors able to track particles in a high-rate environment, up to 10MHz/cm2, ...keeping a stable gain and a good spatial resolution. To pursue our goal, we had to reduce the occupancy by increasing the detector granularity and this has been done by changing the read-out anodes from the usual strips to pads. This minor change in the electrodes layout drastically increased the difficulty of implementing a resistive structure to protect the anodes from sparking. We present the results of the tests performed on four prototypes, with different protection schemes, showing it is possible to reach the desired rate with high gain, high efficiency and good position resolution. The response to X-rays from low (55Fe source) to high (X-rays generator) rates, as well as to beams of ionizing particles is reported.
ABSTRACT The cosmic-ray hydrogen and helium (1H, 2H, 3He, 4He) isotopic composition has been measured with the satellite-borne experiment PAMELA, which was launched into low-Earth orbit on board the ...Resurs-DK1 satellite on 2006 June 15. The rare isotopes 2H and 3He in cosmic rays are believed to originate mainly from the interaction of high-energy protons and helium with the galactic interstellar medium. The isotopic composition was measured between 100 and 1100 MeV/n for hydrogen and between 100 and 1400 MeV/n for helium isotopes using two different detector systems over the 23rd solar minimum from 2006 July to 2007 December.
We present the development of resistive Micromegas aiming at operation under high rates, up to tens MHz/cm2, focusing on the optimisation of the spark protection resistive layer and the ...miniaturisation of the readout elements. Several Micromegas detectors have been built with an anode plane matrix of 48x16 rectangular readout pads, each pad 0.8x2.8 mm2. The detectors differ for the spark protection resistive schemes being realised with the following techniques: a pad-patterned embedded resistor by screen printing, and uniform DLC (Diamond Like Carbon structure) layers. Characterisation and performance studies of the detectors have been carried out by means of radioactive sources, X-Rays, and test beam. A comparison of the performance obtained with the different resistive layouts is presented, in particular focusing on the response under high irradiation and high rate exposure.
We present a precise measurement of downward going albedo proton fluxes for kinetic energy above ∼70 MeV performed by the Payload for Antimatter Matter Exploration and Light‐nuclei Astrophysics ...(PAMELA) experiment at an altitude between 350 and 610 km. On the basis of a trajectory tracing simulation, the analyzed protons were classified into quasi‐trapped, concentrating in the magnetic equatorial region, and untrapped spreading over all latitudes, including both short‐lived (precipitating) and long‐lived (pseudotrapped) components. In addition, features of the penumbra region around the geomagnetic cutoff were investigated in detail. PAMELA results significantly improve the characterization of the high‐energy albedo proton populations at low‐Earth orbits.
Key Points
A new and accurate study of HE reentrant albedo protons based on PAMELA data
Different components identified and reconstructed by trajectory tracing methods
Significant fluxes of pseudotrapped protons were found in the penumbra region
We present the development of resistive Micromegas with small pad readout aiming at precision tracking without efficiency loss up to several MHz/cm2. Several prototypes have been built with the spark ...protection resistive layer deposited with different techniques: a pad-patterned embedded resistor layout with screen printing, and a uniform layer by sputtering (Diamond Like Carbon structure). All detectors consist of a matrix of 48 × 16 rectangular shaped pads with a pitch of (1 × 3) mm2. The active surface is (48 × 48) mm2 with a total number of 768 channels, routed off-detector for readout. Characterization and performance studies of all prototypes have been carried out by means of radioactive sources, X-rays, cosmic rays and high energy particle beams. A comparison of prototypes with different resistivity layout will be presented.
Small-pads resistive Micromegas prototype Di Donato, C.; Alviggi, M.; Camerlingo, M.T. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
04/2020, Letnik:
958
Journal Article
Recenzirano
Detectors at future accelerators will require operation at rates up to three orders of magnitude higher than 15 kHz/cm2 the hit rates expected in the current upgrades forward muon detectors of LHC ...experiments. A resistive Micromegas detectors with modified readout system can achieve rate capability up to few MHz/cm2 low occupancy. We present the development of small-pad Micromegas detectors with a pad resistive readout of few mm2 in size, built with the spark protection resistive layer realized with different techniques.
The cosmic ray (CR) lithium and beryllium (6Li, 7Li, 7Be, 9Be, 10Be) isotopic composition has been measured with the satellite-borne experiment PAMELA, which was launched into low-Earth orbit on ...board the Resurs-DK1 satellite on 2006 June 15. The rare lithium and beryllium isotopes in CRs are believed to originate mainly from the interaction of high-energy carbon, nitrogen, and oxygen nuclei with the interstellar medium (ISM), but also on "tertiary" interactions in the ISM (i.e., produced by further fragmentation of secondary beryllium and boron). In this paper, the isotopic ratios 7Li/6Li and 7Be/(9Be + 10Be), measured between 150 and 1100 MeV n−1 using two different detector systems from 2006 July to 2014 September, will be presented.
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