Search results for "Gamma ray spectroscopy"
showing 10 items of 18 documents
Contributions to Phase Two of AGATA electronics
2020
En el campo de la física nuclear, la espectroscopia de rayos gamma de alta resolución es un método preciso para estudiar la estructura del núcleo, extrayendo la energía y la distribución angular de los fotones gamma emitidos en las transiciones entre estados nucleares. Para obtener núcleos en un estado excitado y por tanto emitan rayos gamma, hemos de hacer chocar la materia, produciendo reacciones nucleares (espectroscopia de haz) o recurrir a desintegraciones radiactivas (espectroscopia de desintegración). Los detectores de semiconductor de germanio de alta pureza (HPGe) han demostrado tener una buena respuesta interaccionando con rayos gamma. Al igual que otros detectores de basados en s…
Development of a 3D CZT detector prototype for Laue Lens telescope
2010
We report on the development of a 3D position sensitive prototype suitable as focal plane detector for Laue lens telescope. The basic sensitive unit is a drift strip detector based on a CZT crystal, (similar to 19x8 mm(2) area, 2.4 mm thick), irradiated transversally to the electric field direction. The anode side is segmented in 64 strips, that divide the crystal in 8 independent sensor (pixel), each composed by one collecting strip and 7 (one in common) adjacent drift strips. The drift strips are biased by a voltage divider, whereas the anode strips are held at ground. Furthermore, the cathode is divided in 4 horizontal strips for the reconstruction of the third interaction position coord…
Experimental results from Al/p-CdTe/Pt X-ray detectors
2013
Recently, Al/CdTe/Pt detectors have been proposed for the development of high resolution X-ray spectrometers. Due to the low leakage currents, these detectors allow high electric fields and the pixellization of anodes with the possibility to realize single charge carrier sensing detectors. In this work, we report on the results of electrical and spectroscopic investigations on CdTe diode detectors with Al/CdTe/Pt electrode configuration (4.1×4.1×0.75 and 4.1×4.1×2 mm3). The detectors are characterized by very low leakage currents in the reverse bias operation: 0.3 nA at 25 °C and 2.4 pA at -25 °C under a bias voltage of -1000 V. The spectroscopic performance of the detectors at both low and…
Performance of a new real time digital pulse processing system for X-ray and gamma ray semiconductor detectors
2014
New generation spectroscopy systems have advanced towards digital pulse processing (DPP) approaches. DPP systems, based on direct digitizing and processing of detector signals, have recently been favoured over analog pulse processing electronics, ensuring better performance. In this work, we present the performance of a new real time DPP system for X-ray and gamma ray semiconductor detectors. The system is based on a commercial digitizer equipped with a custom DPP firmware, developed by our group, for on-line pulse shape and height analysis. X-ray and gamma ray spectra measurements with cadmium telluride (CdTe) and germanium (Ge) detectors, coupled to resistive feedback preamplifiers, will …
Charge transport properties in CdZnTe detectors grown by the vertical Bridgman technique
2011
Presently, a great amount of effort is being devoted to the development of CdTe and CdZnTe (CZT) detectors for a large variety of applications such as medical, industrial, and space research. We present the spectroscopic properties of some CZT crystals grown by the standard vertical Bridgman method and by the boron oxide encapsulated vertical Bridgman method, which has been recently implemented at IMEM-CNR (Parma, Italy). In this technique, the crystal is grown in an open quartz crucible fully encapsulated by a thin layer of liquid boron oxide. This method prevents contact between the crystal and the crucible, thereby allowing larger single grains with a lower dislocation density to be obta…
Optimization of quasi-hemispherical CdZnTe detectors by means of first principles simulation
2023
AbstractIn this paper we present the development of quasi-hemispherical gamma-ray detectors based on CdZnTe. Among the possible single-polarity electrode configurations, such as coplanar, pixelated, or virtual Frisch-grid geometries, quasi-hemispherical detectors are the most cost-effective alternative with comparable raw energy resolution in the high and low energy range. The optimal configuration of the sensor in terms of dimension of the crystals and electrode specifications has been first determined by simulations, and successively validated with experimental measures. Spectra from different sources have been acquired to evaluate the detectors performances. Three types of detectors with…
Electric field manipulation in Al/CdTe/Pt detectors under optical perturbations
2017
Abstract Al/CdTe/Pt detectors are very attractive devices for high-resolution X-ray spectroscopy, even though they suffer from polarization phenomena, which cause a progressive time degradation of the spectroscopic performance. In this work we investigated on the time dependence of the electric field of an Al/CdTe/Pt detector under optical perturbation by means of Pockels effect measurements. A tunable laser with wavelengths ranging within 700−1000 nm and a 940 nm light emitting diode (LED) were used. The measurements of both the electric field profile and the total current were used to better understand the effects of the optical perturbation on polarization phenomena. The results point ou…
Real time digital pulse processing for X-ray and gamma ray semiconductor detectors
2013
Abstract Digital pulse processing (DPP) systems, based on direct digitizing and processing of detector signals, have recently been favoured over analog electronics, ensuring higher flexibility, stability, lower dead time and better spectroscopic performance. In this work, we present the performance of a new real time DPP system for X-ray and gamma ray semiconductor detectors. The system is based on a commercial digitizer equipped with a custom DPP firmware, developed by our group, for on-line pulse height and shape analysis. X-ray and gamma ray spectra measurements with cadmium telluride (CdTe) and germanium (Ge) detectors highlight the excellent performance of the system both at low and hi…
Time-dependent electric field in Al/CdTe/Pt detectors
2015
Abstract Al/CdTe/Pt detectors are very attractive devices for high-resolution X-ray spectroscopy, even though they suffer from bias-induced time instability (polarization). Polarization phenomena cause a progressive time-degradation of the spectroscopic performance of the detectors, due to hole trapping and detrapping from deep acceptor levels that directly control the electric field distribution. In this work we present experimental investigations on the electric field profile of planar Al/CdTe/Pt detectors by means of Pockels effect measurements. The time/temperature dependence of the electric field was investigated in a long time window (up to 10 h) and the correlation with the reverse c…
High-spin states beyond the proton drip-line: Quasiparticle alignments in 113 Cs
2014
Abstract Excited states have been studied in the deformed proton emitter 113Cs. Gamma-ray transitions have been unambiguously assigned to 113Cs by correlation with its characteristic proton decay, using the method of recoil-decay tagging. Two previously identified rotational bands have been observed and extended to tentative spins of 45/2 and 51 / 2 ħ , with excitation energies over 8 MeV above the lowest state. These are the highest angular momenta and excitation energies observed to date in any nucleus beyond the proton drip-line. Transitions in the bands have been rearranged compared to previous work. A study of aligned angular momenta, in comparison to the predictions of Woods–Saxon cra…