This paper presents a new, home-made, GVM (Generating Voltmeter) ion beam energy stabilization system, currently in operation at the Bucharest Tandem Van de Graaff accelerator. The new design ...combines the signal from the GVM preamplifier with the signal of an original digital reference, in order to obtain an error signal needed by the high-voltage stabilization loop. It is shown that the structure of the employed algorithm provides a high efficiency operation mode for the slow variation of accelerating voltage, with the exception of discharges in the high voltage system. The block structure design, construction features, and tests of this new stabilization system are reported in detail.
Four different combinations of 9644Ru and 9640Zr nuclei, both as projectile and target, were investigated at the same bombarding energy of 400A MeV using a 4pi detector. The degree of isospin mixing ...between projectile and target nucleons is mapped across a large portion of the phase space using two different isospin-tracer observables, the number of measured protons and the tritium to 3He yield ratio. The experimental results show that the global equilibrium is not reached even in the most central collisions. Quantitative measures of stopping and mixing are extracted from the data. They are found to exhibit a quite strong sensitivity to the in-medium ( n,n) cross section used in microscopic transport calculations.
We have refurbished and tested a neutron array composed of 81 BC400 plastic scintillator detectors dedicated for neutron measurements in future fusion–fission experiments The Neutron Array (NA) ...detectors, installed at the 9 MV Tandem accelerator facility of the Horia Hulubei National Institute for R&D in Physics and Nuclear Engineering (IFIN-HH), have been refurbished and the data acquisition system has been updated. We present the characteristics and performances of the NA and of the associated electronics.
Experimental data on K
+ meson and proton sideward flow measured with the FOPI detector at SIS/GSI in the reactions Ru+Ru at 1.69
A GeV and Ni+Ni at 1.93
A GeV are presented. The K
+ sideward flow is ...found to be anti-correlated (correlated) with the one of protons at low (high) transverse momenta. When compared to the predictions of a transport model, the data favour the existence of an in-medium repulsive K
+-nucleon potential.
Mass and charge identification of charged products detected with Silicon–CsI(Tl) telescopes of the Chimera apparatus are presented. An identification function, based on the Bethe–Bloch formula, is ...used to fit empirical correlations between Δ
E and
E ADC readings, in order to determine, event by event, the atomic and mass numbers of the detected charged reaction products prior to energy calibration.
Collisions of Au on Au at incident energies of 150, 250 and 400
A·MeV were studied with the FOPI-facility at GSI Darmstadt. Nuclear charge (
Z ⩽ 15) and velocity of the products were detected with ...full azimuthal acceptance at laboratory angles 1° ⩽
θlab ⩽ 30°. Isotope separated light charged particles were measured with movable multiple telescopes in an angular range of 6–90°. Central collisions representing about 1% of the reaction cross section were selected by requiring high total transverse energy, but vanishing side flow. The velocity space distributions and yields of the emitted fragments are reported. the data are analysed in terms of a thermal model including radial flow. A comparison with predictions of the quantum molecular model is presented.
We report on the first analysis of directed and elliptic flow with the new method of Lee-Yang zeros. Experimental data are presented for Ru+Ru reactions at 1.69A GeV measured with the FOPI detector ...at SIS/GSI. The results obtained with several methods, based on the event-plane reconstruction, on Lee-Yang zeros, and on multiparticle cumulants (up to fifth order) applied for the first time at SIS energies, are compared. They show conclusive evidence that azimuthal correlations between nucleons and composite particles at this energy are largely dominated by anisotropic flow.
A large-area glass-resistive plate chamber with multistrip readout Petrovici, M.; Herrmann, N.; Hildenbrand, K.D. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
07/2002, Letnik:
487, Številka:
3
Journal Article
Recenzirano
Odprti dostop
A completely new configuration of a glass resistive-plate chamber (GRPC) was built and tested. It consists of a double two-gap structure of electrodes with an active area of about
400
cm
2
and is ...read out via a central multistrip printed circuit board. In measurements with a
60
Co
source and p, d particles of
1.5
A
GeV
time resolutions better than
80
ps
, position resolution along the strips of 5–
6
mm
and efficiencies larger than 95% were obtained using available fast standard electronics. These results open the possibility of constructing compact TOF detectors of high resolution and high granularity.
Multistrip multigap symmetric RPC Petrovici, M.; Herrmann, N.; Hildenbrand, K.D. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
08/2003, Letnik:
508, Številka:
1-2
Journal Article
Recenzirano
Odprti dostop
The characteristics of a symmetric multigap resistive plate chamber with multistrip readout electrode, recently developed by us, continued to be investigated. Studies of the time resolution, ...efficiency, average charge and dark rate as a function of applied voltage and the influence of the angle of incidence of the detected particle on these observables have been performed. Different type of discriminators have been tested.
High counting rate transition radiation detector Petriş, M.; Petrovici, M.; Simion, V. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
10/2007, Letnik:
581, Številka:
1
Journal Article
Recenzirano
A new Transition Radiation Detector (TRD) prototype with high granularity for a high counting rate environment, required by the CBM experiment at the future experimental facility FAIR, GSI-Darmstadt, ...was designed and built. A solution for such a detector is a multiwire proportional chamber with a minimized drift region, reduced to a cathode – readout pad plane distance of 6
mm and a multiwire anode plane in the middle. Results of the
Fe
55
source tests and of the in-beam investigations of the rate capability in terms of signal deterioration and position resolution degradation with the increase of the counting rate are presented. Based on the measured deposited energy spectra, the discrimination between electrons and pions as a function of number of layers was estimated by Monte Carlo simulations.
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