R. Berjillos

Performance of Monocrystalline Diamond Radiation Detectors Fabricated Using TiW, Cr/Au and a Novel Ohmic DLC/Pt/Au Electrical Contact

Diamond radiation detectors are able to detect deep UV photons, X-rays, gamma rays, electrons, alpha particles, charged ions and neutrons, with a dynamic range in energies spanning from 5.5 eV up to GeV of cosmic rays. Since the bandgap of diamond is 5.5 eV this equates into negligible dark current noise at room temperature with no need for cooling. Metal diamond interfaces play a key role in the performance of the detectors as different metallization techniques lead to either ohmic or Schottky electrical contacts. We investigated the performance of synthetic high purity monocrystalline diamond radiation detectors fabricated with TiW, Cr/Au and a novel metallization technique utilising diamond-like carbon tunnelling junction and Pt/Au as electrical contacts. The investigation was carried out under irradiation with Co-60 γ-rays, Sr-90 electrons and Am-241 α-particles. The experimental results with respect to I –V dark current levels, irradiation photocurrent, signal-to-noise ratio and time response have been compared and discussed. Results show an ohmic behaviour of the DLC/Pt/Au contact, a charge collection efficiency of 100% at an applied electric field of 0.377 V/um for all electrical contacts (under Sr-90 electrons irradiation) at a correspondent dark current value of less than a picoAmpere.The single crystal CVD DLC/Pt/Au diamond radiation detector reported here shows spectroscopic energy resolution of 1.1% at an applied voltage of +450 volts under 5.5 MeV alpha particle irradiation; the experiments also showed a fast response of the novel contact with a transit time pulse of 6 ns. No ‘memory’ or ‘pumping’ effect was observed for the DLC/Pt/Au contact at positive bias; the signal was also stable (fluctuations below 0.5%) and reproducible under Co-60 irradiation, with a signal to noise ratio ≫ 10000:1 and a linearity in the dose rate response.

FARCOS: A versatile and modular Femtoscopy Array for Correlations and Spectroscopy

In the framework of multi-fragmentation experiments the evolution towards two(or more) particle correlations with stable and radioactive beams calls for the development of a novel detection system featuring high angular and energy resolution and able to reconstruct the particles momentum at high precision. The proposed detection system, named FARCOS (Femtoscopy ARray for COrrelations and Spectroscopy) will be beneficial for different physical cases. To this aim we are building a prototype detection system featuring four telescopes. Each telescope features an active area of 6.4 cm × 6.4 cm and is composed of three detection stages. The first ΔE stage is a Double Sided Silicon Strip Detector (DSSSD), 300 μm thick, featuring 32 × 32 strips. The second ΔE stage is again a DSSSD, 1500 μm thick, featuring 32 × 32 strips. The third stage, acting as calorimeter, is composed by four CsI(TI) crystals with an active area of 3.2 cm × 3.2 cm and an absorption length of 6 cm forming a 2 × 2 matrix. The scintillators are readout by a Silicon photodiode 300 μm thick. The paper presents the relevant features of FARCOS and the expected performance of the silicon detection layers, with a special focus on the requirements of the frontend electronics for the DSSSD and the qualification of the DSSSD. In addition we report the first results of the preliminary on-beam tests.

Mapping the amplitude and position response of double sided silicon strip detectors with monochromatic single protons

We are currently developing a novel detection system featuring high angular and energy resolution and able to reconstruct the particles momentum at high precision for different physical cases in multi-fragmentation nuclear physics experiments, based on Double Sided Silicon Strip Detectors as ΔE stages aimed at performing also pulse shape analysis for fragments stopping therein. We carried out a detailed qualification of the performance of the strip detectors. In order to provide the detector response matrix we used a pulsed monoenergetic proton beam. The paper reviews the pulsed proton beam facility of the LaBeC of INFN - Sezione di Firenze and present the results of the characterization of the DSSSD prototypes with the pulsed proton beam. In particular we will discuss the amplitude and time response mapping and we will present the analysis of the dependence of the signal shape as a function of the position of interaction.

Interaction of He8 with Pb208 at near-barrier energies: He4 and He6 production

The authors would like to thank the staff of the GANIL accelerator facility for providing the high-quality 8He beam. This work was supported in part by Grants No. FPA-2010-22131-CO2-01 (FINURA) and No. FPA2013-47327-C2-1-R from the Spanish Ministry of Economy and Competitiveness, UNAM-PAPIIT IA103218 (Mexico); Grant No. N202 033637 from the Ministry of Science and Higher Education of Poland; the National Science Centre of Poland under Contracts No. 2013/08/M/ST2/00257 (LEA-COPIGAL) and No. 2014/14/M/ST2/00738 (COPIN-INFN Collaboration); and Grant No. EUI2009-04163432 (EUROGENESIS) from the European Science Foundation.

A Compact Detector for Studying Heavy Ion Reactions: GLORIA

In this work we present the GLObal ReactIon Array (GLORIA), a compact silicon array which has been build in order to study heavy ion reactions involving radioactive beams . It has been used for the first time at the SPIRAL-GANIL facility in Caen (France), for studying the scattering of the system \(^{8}\)He + \({^{208}}\)Pb at energies around the Coulomb barrier.

Study of the near-barrier scattering of 8 He on 208 Pb

G. Marquinez-Duran et al. ; 6 pags., 3 figs. ; Presented at the XXXIV Mazurian Lakes Conference on Physics, Piaski, Poland, September 6–13, 2015.

Study of the Near-barrier Scattering of He-8 on Pb-208

G. Marquinez-Duran et al. ; 6 pags., 3 figs. ; Presented at the XXXIV Mazurian Lakes Conference on Physics, Piaski, Poland, September 6–13, 2015.

Scattering of 8He on 208Pb at 22 MeV

The skin nucleus {sup 8}He is investigated by measuring the angular distribution of the elasticly scattered {sup 8}He and the {sup 6,4}He fragments produced in the collision with a {sup 208}Pb target at 22 MeV, just above the Coulomb barrier. The experiment was carried out at SPIRAL/GANIL in 2010. Here we present preliminary results for the elastic scattering.

Sub-barrier Fusion and Breakup of Light Halo Nuclei

In this work we present new data for the sub‐barrier fusion of the system 6He+206Pb obtained in the Centre de Recherches du Cyclotron (UCL), in Louvain‐la‐Neuve, Belgium. The preliminary results suggest the absence of fusion enhancement at sub‐barrier energies.