[en] The direct photon measurement can provide information about the thermal evolution of the hot dense nuclear matter produced in ultra- relativistic heavy-ion collisions. However, the measurement of the transverse momentum distribution of the thermal photons is essential to obtain detailed information, in particular, about the short-lived initial hot phase. To date there has been no confirmed observation of direct thermal photon radiation in the transverse momentum region below about 3 GeV/c. On the other hand, the upper limit on the direct photon yield in S + Au reactions at large transverse momenta determined by the WA80 experiment has been shown to imply that the initial temperature of the system must be relatively low (< 250 MeV). Such low temperatures imply that the system has access to a large number of degrees of freedom, consistent with QGP formation or with a hadronic system consisting of the full spectrum of known resonances up to large mass, but inconsistent with a hadronic gas of only the lowest lying resonances. It is an interesting question how a hadronic gas consisting of the full spectrum of resonances could come into chemical equilibrium already during the initial phase of the interaction. Preliminary results from WA98 for Pb + Pb reactions indicate that there is no significant integrated direct photon excess in central collisions compared to peripheral collisions. This conclusion is based on the variation of the ratio of the electromagnetic to total transverse energy with centrality, which is consistent with no increase. The analysis of the photon data obtained with the WA98 leadglass detector is underway. Comparison of the preliminary inclusive photon spectrum to recent theoretical predictions for the thermal direct photon signal indicate that it may be observable for the case of a hadron gas, but is likely below the expected level of sensitivity for the case of QGP formation

[en] The unrecognized oxidation of plutonium in open-quotes sealedclose quotes canisters poses a unique problem for both material control and accountability. A feasibility study was performed to address the use of randomly pulsed neutron measurements with ²⁵²Cf to determine if plutonium metal in a canister has oxidized without opening the container. The Monte Carlo code MCNP-DSP was used to determine if time-of-flight transmission measurements could be used to determine oxidation of plutonium in open-quotes sealedclose quotes cans. In the Monte Carlo models, a plutonium button in a can was positioned between a ²⁵²Cf source and a scintillation detector, and the time distribution of counts after ²⁵²Cf fission in the detector was calculated. The time distribution of counts after ²⁵²Cf fission differs between plutonium metal and plutonium oxide because resonances in oxygen will affect transmission of certain energy neutrons from ²⁵²Cf sources in ionization chambers. This method could be used to determine the presence of other materials that react with plutonium in open-quotes sealedclose quotes cans

[en] A detector and front-end electronics unit with secure data transmission has been designed and implemented for a fissile mass flow monitoring system for fissile mass flow of gases and liquids in a pipe. The unit consists of 4 bismuth germanate (BGO) scintillation detectors, pulse-shaping and counting electronics, local temperature sensors, and on-board local area network nodes which locally acquire data and report to the master computer via a secure network link. The signal gain of the pulse-shaping circuitry and energy windows of the pulse-counting circuitry are periodicially self calibrated and self adjusted in situ using a characteristic line in the fissile material pulse height spectrum as a reference point to compensate for drift such as in the detector gain due to PM tube aging. The temperature- dependent signal amplitude variations due to the intrinsic temperature coefficients of the PM tube gain and BGO scintillation efficiency have been characterized and real-time gain corrections introduced. The detector and electronics design, measured intrinsic performance of the detectors and electronics, and the performance of the detector and electronics within the fissile mass flow monitoring system are described

[en] The US Department of Energy and the US Department of the Interior agreed to monitor water-level data in 16 observation wells located at Hallam Facility, Hallam, Nebraska. The data collection period began in September 1993 and continued through August 1994. This report contains the interim summary representing six months of data collection. Specific sections include the following: description of the US Geological Survey's monitoring program at the Hallam Nuclear Facility (Sept. 1993 to Feb. 1994); description of the collection of continuous water-level data; description of the collection of monthly water-level data; table of observation well number, latitude, longitude, and depth; table of monthly ground-water levels data; table of recorder wells, rainfall, and barometric pressure unit values; and table of recorder well, rainfall, and barometric daily values; hydrographs of selected wells

[en] The paper presents a field trial held in EDF's R and D laboratories concerning smart field instruments (sensors, I/O modules, transmitters) operating on the WorldFIP field-bus. The trial put into operation a supervisory control and data acquisition (SCADA) system on the field-bus with available industrial field devices and software tools. The field trial enables EDF's teams to address the inter-operability issue regarding smart field devices and to prepare the forthcoming step from analog to fully digital measurement technology by evaluating new services and higher performances provided. Possible architectures for process control and on-site testing purposes have been identified. A first application for a flow-measuring rig is under way. It implements a WorldFIP field-bus based DCS with FIP/HART multiplexers, FIP and HART smart devices (sensors and actuators) and a field management system. (authors)

[en] Concrete structures which are encountered at EDF, like all civil engineering structures, age. In order to adapt the maintenance conditions of these structures, particularly to extend their service life, and also to prepare constructions of future structures, tools for predicting the behaviour of these structures in their environment should be available. For EDF the technical risks are high and consequently very appropriate R and D actions are required. In this context the Direction des Etudes et Recherches (DER) has developed a methodology for analysing concrete structure behaviour modelling. This approach has several aims: - making a distinction between the problems which refer to the existing models and those which require R and D; - displaying disciplinary links between different problems encountered on EDF structures (non-linear mechanical, chemical - hydraulic - mechanical coupling, etc); - listing of the existing tools and positioning the DER 'Aster' finite element code among them. This document is a state of the art of scientific knowledge intended to shed light on the fields in which one should be involved when there is, on one part a strong requirement on the side of structure operators, and on the other one, the present tools do not allow this requirement to be satisfactorily met. The analysis has been done on 12 scientific subjects: 1) Hydration of concrete at early ages: exothermicity, hardening, autogenous shrinkage; 2) Drying and drying shrinkage; 3) Alkali-silica reaction and bulky stage formation; 4) Long term deterioration by leaching; 5) Ionic diffusion and associated attacks: the chlorides case; 6) Permeability / tightness of concrete; 7) Concretes -nonlinear behaviour and cracking (I): contribution of the plasticity models; 8) Concretes - nonlinear behaviour and cracking (II): contribution of the damage models; 9) Concretes - nonlinear behaviour and cracking (III): the contribution of the probabilistic analysis model; 10) Delayed behaviour of concrete (CREEP); 11) Allowing for reinforcement and prestressing; 12) Dynamic behaviour: seismic effects, shock analysis. (authors)

[en] SISSI is a two solenoid superconductors ensemble of strong focusing power which permits increasing the angular aperture of the beam lines for secondary ions produced by fragmentation upon a target placed between the two solenoids. The document contains five sections. The first devoted to the SISSI description presents the equipment, the target holder and the targets. The second presents the optics of secondary beam transport with and without wedge in the alpha spectrometer. The third section presents the detectors available for secondary beams: gas beam profilers, silicon detectors, position sensitive detectors, and the booster device. The fourth section deals with the experiment preparation and the final one describes the procedures for tuning the secondary beams produced with SISSI

[en] Read out the absorbance of a dosimetric foil is accomplished by two beam spectrophotometer. Such a solution makes possible the compensation of light source instabilities and ensures higher stability of the dose reader. The error of absorbance measurement caused by the instabilities does not exceed 0.0004 A. (author)

[en] The instrument to measure Am-241 and Cs-137 radiation consisting of scintillation probe, two measuring channels and a photomultiplier automatic gain control circuit was investigated in respect to its operating stability and measuring errors. The instability of the count rate does not exceed 0.15 % of the PM gain variation ±50 % relative to nominal one. The effective time constant of the AGC loop ≤1 sec, and after the mains is interrupted and switched again the instrument restarts its operation and stabilizes the PM gain in the period not longer than 10 sec since the moment the mains is switched on. (author)

[en] The leakage doses due to scattered photon from the concrete floor of the synchrotron radiation beamline hutch, so called ground shine, have been calculated by using a general purpose gamma-ray scattering code G33-GP2 for it ranging from 30 keV to 2.5 MeV. Calculations were performed for three geometries, the geometries with lead bands equipped along the foot of the inside and outside the hutch wall, and that with the bottom part of hutch wall buried in the concrete floor. Validity of the calculation was verified by comparing its calculation with those using a Monte Carlo code ITS3.0. The total leakage dose outside the hutch has been estimated for the case of the typical wiggler, undulator and bending-magnet beamlines of SPring-8, showing that the dose due to ground shine is found to be a serious issue for the 8 GeV class synchrotron radiation beamline and that the lead band set along the foot of the outside hutch is found to be the most beneficial for shielding the ground shine. (author)