Search results for "SCINTILLATOR"
showing 10 items of 172 documents
Construction, Commissioning and First Results of a Highly Granular Hadron Calorimeter with SiPM-on-Tile Read-out
2018
The CALICE collaboration is developing a highly granular Analogue Hadron sampling CALorimeter (AHCAL) for a future electron-positron collider. Very small detection units are required for the AHCAL due to an optimized design for the Particle Flow Algorithm. This is realized with scintillator tiles each wrapped in reflector foil and individually read out by a silicon photomultiplier (SiPM). These scintillator tiles and SiPMs are assembled on readout boards (HCAL Base Unit, HBU) which are integrated later on in the AHCAL detector stack. With this design a higher energy resolution is achievable, but also a large quantity of components (around 8,000,000 scintillator tiles and SiPMs) are needed t…
The LHCf detector at the CERN Large Hadron Collider
2008
LHCf is an experiment dedicated to the measurement of neutral particles emitted in the very forward region of LHC collisions. The physics goal is to provide data for calibrating the hadron interaction models that are used in the study of Extremely High-Energy Cosmic-Rays. This is possible since the laboratory equivalent collision energy of LHC is 10(17) eV. Two LHCf detectors, consisting of imaging calorimeters made of tungsten plates, plastic scintillator and position sensitive sensors, are installed at zero degree collision angle +/- 140m from an interaction point (IP). Although the lateral dimensions of these calorimeters are very compact, ranging from 20 mm x 20 mm to 40 mm x 40 mm, the…
(γ,2N) reaction inC12
1995
The $^{12}$C(\ensuremath{\gamma},pn) and $^{12}$C(\ensuremath{\gamma},pp) reactions have been measured for photon energies between 80 and 157 MeV using a photon tagging spectrometer and plastic scintillator detectors. The overall energy resolution was \ensuremath{\sim}7 MeV, sufficient to determine the initial shells of the emitted nucleons. Corrections were made for solid angle and threshold effects by means of Monte Carlo simulations. For the (\ensuremath{\gamma},pn) reaction both the missing energy and recoil momentum distributions are largely consistent with a two-nucleon absorption process on p-shell an sp nucleon pairs. For the much smaller $^{12}$C(\ensuremath{\gamma},pp) cross secti…
Background and muon counting rates in underground muon measurements with a plastic scintillator counter based on a wavelength shifting fibre and a mu…
2010
AbstractIn this short note we present results of background measurements carried out with polystyrene based cast plastic 12.0×12.0×3.0 cm3 size scintillator counter with a wavelength shifting fibre and a multi-pixel Geiger mode avalanche photodiode readout in the Baksan underground laboratory at a depth of 200 metres of water equivalent. The total counting rate of the scintillator counter measured at this depth and at a threshold corresponding to ∼0.37 of a minimum ionizing particle is approximately 1.3 Hz.
The next generation nuclear instruments: AGATA and NEDA, and nuclear structure studies near N=Z line
2017
The first part of this thesis is devoted to the development of a large array of neutron detectors NEDA (NEutron Detector Array) and their conceptual design using Monte-Carlo simulations. Prior to the development of NEDA, the neutron detection with liquid scintillators is discussed in Chapter 2. In Chapter 3, the design criteria and simulations of NEDA are discussed. NEDA aims to build a neutron detector array with high efficiency, based on liquid scintillators. NEDA will be coupled to the high-purity γ-ray detector arrays, like AGATA, EXOGAM, to be used as a trigger or complementary detector in the contemporary nuclear physics experiments, which aim to investigate the structure of the exoti…
Beta-delayed neutron decay of 33Na
2002
Abstract Beta-delayed neutron decay of 33 Na has been studied using the on-line mass separator ISOLDE. The delayed neutron spectra were measured by time-of-flight technique using fast scintillators. Two main neutron groups at 800(60) and 1020(80) keV were assigned to the 33 Na decay, showing evidence for strong feeding of states at about 4 MeV in 33 Mg. By simultaneous β–γ–n counting the delayed neutron emission probabilities P 1n =47(6)% and P 2n =13(3)% were determined. The half-life value for 33 Na, T 1/2 =8.0(3) ms , was measured by three different techniques, one employing identifying gamma transitions and two employing beta and neutron counting.
Silicon as an Unconventional Detector in Positron Emission Tomography.
2012
Positron emission tomography (PET) is a widely used technique in medical imaging and in studying small animal models of human disease. In the conventional approach, the 511 keV annihilation photons emitted from a patient or small animal are detected by a ring of scintillators such as LYSO read out by arrays of photodetectors. Although this has been a successful in achieving ~5mm FWHM spatial resolution in human studies and ~1mm resolution in dedicated small animal instruments, there is interest in significantly improving these figures. Silicon, although its stopping power is modest for 511 keV photons, offers a number of potential advantages over more conventional approaches. Foremost is it…
Study of the neutron-rich nuclei with $N$ = 21, $^{35}$Si and $^{33}$Mg, by beta decay of $^{35}$Al and $^{33}$Na
2000
Abstract The first information on the level structure of the N =21 nuclei, 35 Si and 33 Mg, has been obtained by the beta decay study of 35 Al and 33 Na, produced by fragmentation of an UC target with 1.4 GeV protons at CERN/ISOLDE. The experimental technique involved β – γ , β – γ – γ , and β –n– γ coincidences, neutron spectra being obtained by time of flight measurements. Gamma detection was made either using large Ge counters or small BaF 2 scintillators (for lifetime measurements). In the case of the 35 Al decay, ( T 1/2 =41.6(2.2) ms), a simple structure has been found for the level scheme of 35 Si ( Z =14, N =21) which has been interpreted with the level sequence : 7/2 − , 3/2 − and …
Level lifetimes in neutron-rich Ru isotopes
1995
The neutron-rich Ru isotopes are situated between the strongly deformed Sr-Zr region with axial deformation of f l _ 0.40 [1] and the spherical Cd-Sn region. Evidence for triaxiality of even-even Ru isotopes has been presented in [2-5], and lifetimes of some of their 2 + states have been measured in fission studies [6-9]. It seems, however, that in these experiments the nearly identical energies of the 2 + ---* 0 + transitions in l~ and 11~ could not be separated. Therefore, high-resolution measurements are required in order to perceive the evolution of deformation with increasing neutron number. So far only few measurements by the delayed-coincidence method [10] have been performed on chem…
Time-of-flight photoelectron emission microscopy TOF-PEEM: first results
1998
The time structure of the synchrotron radiation at BESSY (Berlin) is used to operate a photoemission electron microscope in a time-of-flight (TOF) mode. The electrons which are emitted from the sample surface with different energies are dispersed in a drift tube subsequent to the imaging optics. The screen of the microscope was replaced by a fast scintillator (tau = 1.4 ns) and the light is detected by an ultra fast gated intensified CCD camera (800 ps gate 1 MHz repetition rate). The resolving power in the energy domain is demonstrated and possible implications on the spatial resolution (chromatic correction) are discussed. Additionally, an improved contrast at very low emission energies i…