Search results for "Instrumentation"
showing 10 items of 4914 documents
Performance of the cost-effective Planacon ® MCP-PMTs in strong magnetic fields
2020
Abstract We present the behavior of the cost-effective Planacon MCP-PMTs with 25 μ m pore diameter in the presence of axial magnetic fields up to 0.5 T. Having a batch of 62 devices of the same type, two MCP-PMTs were selected and their gain variation measured in different magnetic fields. These two otherwise identical devices satisfied the selection criteria by requiring the lowest (1.15 kV) and one of the highest (1.4 kV) bias voltage values to achieve a given gain. Both MCP-PMTs have a nearly identical tolerance of the strong magnetic field despite the significant difference in the bias voltage. This clarifies the mechanism of the B-field influence on the MCP-PMT gain, emphasizing the im…
Performance of a gamma-ray tracking array: Characterizing the AGATA array using a 60Co source
2017
International audience; The AGATA (Advanced GAmma Tracking Array) tracking detector is being designed to far surpass the performance of the previous generation, Compton-suppressed arrays. In this paper, a characterization of AGATA is provided based on data from the second GSI campaign. Emphasis is placed on the proper corrections required to extract the absolute photopeak efficiency and peak-to-total ratio. The performance after tracking is extracted and GEANT4 simulations are used both to understand the results and to scale the measurements up to predicted values for the full 4π implementation of the device.
EUSO-A Space mission searching for Extreme Energy Cosmic Rays and neutrinos
2004
The “Extreme Universe Space Observatory – EUSO” is an international, multi-agency mission, led by ESA, aimed at measuring from a Low Altitude Earth Orbiting Space Platform the flux and investigating the nature and origin of the charged and neutral particles of the Extreme Energy Cosmic Ray (EECR) with energy above the conventional value (E = 5×10 19 eV) of the Greisen Zatsepin and Kuzmin (GZK) effect E GZK = 5×10 19 eV). EUSO will pioneer the observation from Space of EECR-induced Extensive Air Showers (EASs), making measurements of the primary energy, arrival direction and possibly composition of the incoming flux by using a sensitive area and target volume far greater than achievable from…
The EM imaging reconstruction method in γ-ray astronomy
1998
Abstract The simpler imaging reconstruction methods used for γ-ray coded mask telescopes are based on correlation methods, very fast and simple-to-use but with limitations in the reconstructed image. To improve these results, other reconstruction methods have been developed, such as the maximum entropy methods or the Iterative Removal Of Sources (IROS). However, such kind of methods are slower and can be impracticable for very complex telescopes. In this paper we present an alternative image reconstruction method, based on an iterative maximum likelihood algorithm called the EM algorithm, easy to implement and that can be successfully used for not very complex coded mask systems, as is the …
Measurement of propagation time dispersion in a scintillator
2007
One contribution to the time resolution of a scintillation detector is the signal time spread due to path length variations of the detected photons from a point source. In an experimental study a rectangular scintillator was excited by means of a fast pulsed ultraviolet laser at different positions along its longitudinal axis. Timing measurements with a photomultiplier tube in a detection plane displaced from the scintillator end face showed a correlation between signal time and tube position indicating only a small distortion of photon angles during transmission. The data is in good agreement with a Monte Carlo simulation used to compute the average photon angle with respect to the detecti…
Recoil-beta tagging: A novel technique for studying proton-drip-line nuclei
2006
Abstract Tagging with charged particles and γ -rays at the focal plane of recoil separators has proven, over the last two decades, to be a very powerful tool for the identification of excited states in exotic nuclei produced with very low cross-sections. One of the key areas so far unexplored in terms of the tagging methodology has been performing correlations with β -particles at the focal plane of a recoil separator. A new technique entitled Recoil-Beta Tagging (RBT) has been developed, this technique exploits the unusual properties of Fermi super-allowed β emitters, which have both a short half-life ( ∼ 100 ms ) and high β + -endpoint energy. Correlating with such β -particles using a do…
Neutron yields from a thick 13C target irradiated by 30 MeV protons
2002
Abstract Total neutron yields resulting from the proton bombardment of a thick 13 C target have been measured for 30 MeV protons. Absolute intensities, angular distributions and energy spectra of neutrons have been obtained by the time-of-flight technique where the detectors provided continuous coverage from 0° to 120°. Resonances have been found, some of which can be attributed to known states in 14 N. A total yield of 0.022(3) n/p was observed with a slight angular anisotropy towards forward angles. The measured yields are compared to the neutron yields produced by using deuterons on thick 12 C and 9 Be targets.
Neutron yield from a 13C thick target irradiated by protons of intermediate energy
2007
Abstract Angular and energy distributions of neutrons produced by the interaction of protons of 20, 25 and 40 MeV in 13C targets, in which they are stopped, have been measured by time-of-flight and activation methods. Neutron yields are compared with a Monte-Carlo based model prediction and with the experimental neutron yields of proton and deuteron beams impinging on natural carbon thick targets. The gain with respect to p + 12C is only sizeable at the lowest proton energies. The neutron yield curve of p + 13C versus proton energy is definitely lower than the one of d + 12C, in contrast to the suggestion by an earlier published measurement at 30 MeV.
Gas-silicon detector telescope for charged particle spectroscopy
1997
Abstract A gas-silicon detector telescope for charged particle spectroscopy has been constructed and tested. The lower detection limits were determined to be 155 keV for protons, 180 keV for deuterons and 350 keV for alpha particles. Typical energy resolution of the telescope measured for beta-delayed protons is 20 keV. Time resolution for the signals of the telescope was measured to be less than 10 ns. Examples of using the detector telescope in detection of beta-delayed proton activities are presented.
A source of polarized electrons based on photoemission of GaAsP.
1990
Abstract The source described is based on photoemission of electrons from 100-GaAs0.62P0.38 activated to negative electron affinity. It is built to inject a beam of polarized electrons into the 350 MeV linear accelerator in Mainz. It is capable of delivering a mean current of 28 μA spin-polarized longitudinally to a degree of 0.44. The lifetime of the cathode under operational conditions is better than 200 h. The source was successfully run in a parity experiment, in which the analysing power of quasielastic scattering from beryllium for longitudinally polarized electrons was measured.