Search results for " scintillation"
showing 10 items of 20 documents
Digital liquid-scintillation counting and effective pulse-shape discrimination with artificial neural networks
2014
Abstract A typical problem in low-level liquid scintillation (LS) counting is the identification of α particles in the presence of a high background of β and γ particles. Especially the occurrence of β-β and β-γ pile-ups may prevent the unambiguous identification of an α signal by commonly used analog electronics. In this case, pulse-shape discrimination (PSD) and pile-up rejection (PUR) units show an insufficient performance. This problem was also observed in own earlier experiments on the chemical behaviour of transactinide elements using the liquid-liquid extraction system SISAK in combination with LS counting. α-particle signals from the decay of the transactinides could not be unambigu…
Analysis of linear alkylbenzene samples with a camera-based equipment
2017
Nestemäisiä tuikeaineita hyödyntävät ilmaisimet ovat saaneet jalansijaa neutriinofysiikassa viime vuosikymmeninä. Perinteisiin Cherenkovin ilmaisimiin niiden etu on suurempi hiukkasten vuorovaikutuksesta aiheutuvan valon tuotto. Lisäksi edullisten, suhteellisen ympäristöystävällisten ja optisesti kirkkaiden tuikeaineyhdisteiden (bentseenin alkyylijohdannaiset) saatavuus mahdollistaa yhä suurempien ilmaisimien rakennuksen. Nestemäisten tuikeaineiden ongelmana on kuitenkin niiden taipumus kerätä epäpuhtauksia itseensä ja niiden muutosalttius UV-säteilyn ja korkeiden lämpötilojen vaikutuksesta. Muutokset heikentävät tuikeaineiden valon tuottoa, ja siksi nestemäisten tuikeaineiden puhdistusta j…
Application of fast solvent extraction processes to studies of exotic nuclides
1998
Fast solvent extraction is a chemical separation method, which can be applied to study exotic nuclides. Since about 1970 the SISAK technique, which is an on-line method based on multi-stage solvent extraction separations, has been successfully used to investigate the nuclear properties of β-decaying nuclides with half-lives down to about one second. During the last decade it has become possible to produce transactinide elements in high enough yields to investigate their chemical properties on a one-atom-at-a-time scale. For this purpose it was necessary to improve and change the detection part of the SISAK system in order to be capable to detect spontaneously fissioning and α-decaying nucli…
High resolution 80Se(n,γ) cross section measurement at CERN n_TOF and development of the novel i-TED detection system
2022
El proceso (-s) de captura lenta de neutrones es responsable de la formación de la mitad de los elementos más pesados que el hierro en el universo. A pesar de la larga escala de tiempo de este proceso, la larga vida media de algunos isótopos inestables a lo largo del flujo de reacción del proceso-s crea puntos de ramificación que conducen a una división de la ruta de la nucleosíntesis. 79Se (t1/2 = 3.27 x 10^5 y) representa uno de los núcleos ramificados-s más relevantes y debatidos por dos razones principales. Por un lado, la existencia de estados excitados de baja energía en el 79Se, cuya población puede variar con la temperatura del medio estelar, hace que el patrón de abundancia local…
SiPMs coated with TPB: coating protocol and characterization for NEXT
2012
[EN] Silicon photomultipliers (SiPM) are the photon detectors chosen for the tracking readout in NEXT, a neutrinoless \bb decay experiment which uses a high pressure gaseous xenon time projection chamber (TPC). The reconstruction of event track and topology in this gaseous detector is a key handle for background rejection. Among the commercially available sensors that can be used for tracking, SiPMs offer important advantages, mainly high gain, ruggedness, cost-effectiveness and radio-purity. Their main drawback, however, is their non sensitivity in the emission spectrum of the xenon scintillation (peak at 175 nm). This is overcome by coating these sensors with the organic wavelength shifte…
Tritium retention measurements by accelerator mass spectrometry and full combustion of W-coated and uncoated CFC tiles from the JET divertor
2016
Abstract Accelerator mass spectrometry (AMS) and the full combustion method (FCM) followed by liquid scintillation counting were applied to quantitatively determine the tritium retention in the tungsten-coated carbon fibre composites (CFC), in comparison to uncoated CFC tiles from the JET divertor. The tiles were adjacent and exposed to plasma operations between 2007 and 2009. The tritium depth profiles are showing that the tritium retention on the W-coated tile was reduced by a factor of 13.5 in comparison to the uncoated tile whereas the bulk tritium concentration is approximately the same for both tiles.
Characterization and performance of the DTAS detector
2018
11 pags., 16 figs., 3 tabs.
Probing the Merits of Different Event Parameters for the Identification of Light Charged Particles in CHIMERA CsI(Tl Detectors With Digital Pulse Sha…
2013
We investigated the merits of different event parameters in the identification of Light Charged Particles (LCPs) with CsI(Tl) scintillators read out by photodiodes at high incident energy (400 MeV/u). This investigation is made possible by digital signal processing the output signals. As in the conventional analogue case, the digitized signals allow the discrimination of light charged particles by computing the fast and slow components. In addition other identification parameters as the rise time of the output pulses of the CsI(Tl) come out nearly for free. Aim of this paper is the investigation of novel identification plots and the probe of their merits, in particular at relativistic energ…
A test of electric charge conservation with Borexino
2015
Borexino is a liquid scintillation detector located deep underground at the Laboratori Nazionali del Gran Sasso (LNGS, Italy). Thanks to the unmatched radio-purity of the scintillator, and to the well understood detector response at low energy, a new limit on the stability of the electron for decay into a neutrino and a single mono-energetic photon was obtained. This new bound, tau > 6.6 10**28 yr at 90 % C.L., is two orders of magnitude better than the previous limit.
Charge reconstruction in large-area photomultipliers
2018
Large-area PhotoMultiplier Tubes (PMT) allow to efficiently instrument Liquid Scintillator (LS) neutrino detectors, where large target masses are pivotal to compensate for neutrinos' extremely elusive nature. Depending on the detector light yield, several scintillation photons stemming from the same neutrino interaction are likely to hit a single PMT in a few tens/hundreds of nanoseconds, resulting in several photoelectrons (PEs) to pile-up at the PMT anode. In such scenario, the signal generated by each PE is entangled to the others, and an accurate PMT charge reconstruction becomes challenging. This manuscript describes an experimental method able to address the PMT charge reconstruction …