Characterization of quasi-projectiles produced in symmetric collisions studied with INDRA Comparison with models

The characterization of hot quasi-projectiles produced in symmetric or quasi-symmetric reactions (Au + Au, Xe + Sn, Ni + Ni, Ar + KCl) at di erent incident energies are estimated by means of two di erent procedures. The advantages and disadvantages of each method are analyzed on the basis of simulations using events produced by two slightly di erent models: HIPSE and ELIE.Comment: A para\^itr

A new functional for charge and mass identification in Delta E-E telescopes

We propose a new functional for the charge and mass identification in Delta E-E telescopes. This functional is based on Bethe's formula, allowing safe interpolation or extrapolation in regions with low statistics. When applied to telescopes involving detectors delivering a linear response, as silicon detectors or ionization chambers, a good mass and charge identification is achieved. For other detectors, as caesium-iodide used as a final member of a telescope, a good accuracy is also obtained except in the low residual energy region. A good identification is however recovered if a non-linear energy dependence of the light output is included.Comment: 16 pages, 8 figures, LaTeX2e + EPS figures reduced in size Submitted to Elsevie

Des appareillages en évolution : détection haute résolution en position et en temps

École thématiqu

A Procedure to Calibrate a Multi-Modular Telescope

A procedure has been developed for the charge, mass and energy calibration of ions produced in nuclear heavy ion reactions. The charge and mass identification are based on a $\Delta$E-E technique. A computer code determines the conversion from ADC channels into energy values, atomic number and mass of the detected fragments by comparing with energy loss calculations through a minimization routine. The procedure does not need prior measurements with beams of known energy and charge. An application of this technique to the calibration of the MULTICS apparatus is described.Comment: 9 pages, Tex file, 3 postscript figures available upon request from [email protected]; to appear in Nucl. Inst. Met

MPGD's spatial and energy resolution studies with an adjustable point-like electron source

11th Vienna Conference on Instrumentation (February 2007) , to appear in the Proceedings (NIM A)International audienceMicropattern Gaseous Detectors (MPGD), like Micromegas or GEM, are used or foreseen in particle physics experiments for which a very good spatial resolution is required. We have developed an experimental method to separate the contribution of the transverse diffusion and the multiplication process by varying the number of primary electrons generated by a point-like source. A pulsed nitrogen laser is focused by an optical set-up on the drift electrode which is made of a thin metal layer deposited on a quartz lamina. The number of primary electrons can be adjusted from a few to several thousands on a spot which transverse size is less than $100 \mu m$ RMS. The detector can be positioned with an accuracy of $1\mu m$ by a motorized three dimensional system. This method was applied to a small Micromegas detector with a gain set between $10^3$ and $2.10^4$ and an injection of 60 to 2000 photoelectrons. Spatial resolutions as small as $5\mu m$ were measured with 2000 primary electrons. An estimation of the upper limit of the relative gain variance can be obtained from the measurements

A large dynamic range integrated front-end for photomultiplier tubes

A full custom analog CMOS circuit for obtaining a photomultiplier readout with a 16 bit resolution over 7 V has been developed. It is part of the R&D program for the photomultiplier tube front-end readout of the Pierre Auger Observatory northern site. It performs signal duplication and amplification with three gains: 0.15, 1 and 6. Each amplifier has a resolution of 10 bit and can measure signals with durations of several microseconds with a good baseline stability, for an input charge of up to tens of nano-Coulombs. The amplification is performed by current feedback amplifiers with a bandwidth of 60 MHz.The input impedance, adapted to the coaxial cables, is stable over the whole working range. A prototype was submitted in April 2004 and successfully tested. The linearity over the working range is less than 1%. It was also successfully tested on the Auger surface detector element installed at Orsay (comprised of a Cherenkov water tank equipped with Photonis XP1805 9” diameter photomultiplier tubes). The resolution over 7 V is 16.6 bit.This circuit is the first step towards a “system-on-a-chip” (SoC) solution for a photomultplier tube readout equipped with a fast ADC for signal digitization. A setup using a single cable for both the signal and the photomultiplier high voltage power supply was shown to be successful

SD electronics: simulations on the dynamic range

The surface detector electronics of the Pierre Auger Observatory is characterized by a large dynamic range due to the variation of the signal intensity of the Cherenkov tanks as a function of the distance from the core. In this paper, we present results of simulations and discuss the impact of the dynamic range on the shower reconstruction

Liquid-gas phase transition in hot nuclei studied with INDRA

Thanks to the high detection quality of the INDRA array, signatures related to the dynamics (spinodal decomposition) and thermodynamics (negative microcanonical heat capacity) of a liquid-gas phase transition have been simultaneously studied in multifragmentation events in the Fermi energy domain. The correlation between both types of signals strongly supports the existence of a first order phase transition for hot nuclei.Comment: 9 pages, 2 figures, Invited talk to Nucleus-nucleus 2003 Moscow June 200

Design of the photomultiplier bases for the surface detectors of the Pierre Auger Observatory

The design of the photomultiplier bases for the surface detectors of the Pierre Auger Observatory is presented. The bleeder is purely resistive. The base comprises two outputs: one from the anode and another one from the last dynode followed by an amplifier. The charge ratio between the anode and the amplified dynode is around 30. The design ensures a low consumption (less than 100 mu A at 2 kV), a stability of the gain and of the base line during the whole period of measurement (20 mu s per event) and for the whole dynamic range (max. 1 to 3x10^4 in amplitude). First measurement with a prototype base on the Hamamatsu R5912 photomultiplier tube are presented

Making the transition to services in the animal health industry

The objective of this paper is to explore the steps and practices involved in the management of the shift to services in the context of the animal health industry. Research was carried on a leading animal health company, comparing and contrasting the transition to services between two of its most important regions. The research demonstrates that the delivery journey of the sales force lies at the core of the service transition, and it has expanded the servitization theory by unfolding the two fundamental processes that organizations experience in the transition to services. These are: the service development strategy; and the sales force delivery. This is the first research to explain the changes in “the sales force delivery” process in selling services as opposed to products. The best practices required to make the shift to services include leveraging customers’ experience, implementing service value and benefits, and building an integrated service team