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CdS0.8Se0.2 crystals doped with Cr2+ at a level of ∼1.2×1018 ions/cm3 were grown by the self-seeded physical vapor transport technique in vertical configuration. The ternary compound was synthesized from a stoichiometric mixture of vacuum sublimed CdS and CdSe. The growth temperature was 950°C and it produced a single crystal free of cracks and precipitates. The absorption peak maximum for Cr2+ ion was found to be at 1.85 μm and its intensity was used to determine the dopant concentration and its axial distribution. The axial and radial uniformity of the S/Se ratio were determined by energy dispersive X-ray spectroscopy and found to be uniform throughout the ingot and practically identical to the composition of the source.

Single crystals of KPb 2 Cl 5 were grown by vertical Bridgman technique from purified and synthesized material doped with Erbium up to a concentration of 5 mol% ErCl 3 . The purification was performed by zone refining at a rate of 3 cm/hr for 30 passes, with a final refining at a rate of 1 mm/hr. Segregation coefficient of Er 3+ ions was found to be ∼0.5 for KPb 2 Cl 5 . The transmission through a 12-mm thick crystal was found to be ∼80%, the mid-infrared and visible up-conversion luminescence spectra are reported.

The need for large, room-temperature gamma-ray spectrometers to be fabricated from a single crystalline section of a cadmium zinc telluride (CZT) boule was recently met by progress in crystal growth of high-resistivity material. The characterization of such large crystals provides us with an opportunity to better understand the detector physics and apply characterization techniques, which were difficult to implement and analyze on smaller crystals. In this study, metal-semiconductor-metal, planar-CZT detectors were fabricated from large (approximately 9 × 9 × 6 mm3), CZT single crystals. We have investigated the relationship between the results of the electric-field mapping via Pockels effect, photoconductivity data, and detector performance. Changes in the surface recombination and device characteristics showing departure from symmetry are caused and revealed by variations in the surface preparation.

We have employed photoluminescence mapping at room temperature of detector grade CZT grown by modified Traveling Heater Method (THM) technique and estimated the spatial variation of Zn composition. The composition was found to be fairly uniform over the major portion of the ingot length except near the conical part of the ingot and the upper part of the ingot. Unlike Bridgman growth technique, no detectable striations were observed. The composition was within ±0.3% over the length little more than 4 cm of the ingot. The growth interface revealed from the composition mapping was found to be reasonably flat.

Chalcopyrite crystals of 6LiInSe2 have recently been shown to respond to gamma and thermal neutron radiation. Thus far, large crystals have been prepared although the charge collection efficiency has not been sufficient for high energy resolution. In an effort to improve energy resolution needed for gamma spectroscopy as well as pulse shape discrimination for mixed gamma neutron fluxes, the precipitate concentration within the 6LiInSe2 crystal have been studied. The precipitate volume greatly affects the energy resolution in the pulse height spectrum. Further, the charge mobility varies greatly with holes being preferentially trapped by these precipitates or some other defect site within the crystal.

Introduction Devant un exantheme febrile du sujet jeune, certains diagnostics doivent etre evoques notamment les causes infectieuses ou une toxidermie. Nous rapportons un cas d’infection bacterienne peu connue responsable d’un exantheme febrile associe a une pharyngite. Observation Un homme de 22 ans etait hospitalise pour une eruption febrile associee a un syndrome grippal et a une odynophagie. A l’examen, on notait un exantheme maculopapuleux rouge vif diffus touchant aussi les extremites. Sur la face interne des cuisses, on notait en sus de l’erytheme un blanchiment au centre des lesions. Il existait une pharyngite et une polyadenopathie cervicale. Le patient rapportait la prise d’ibuprofene et de Rhinadvil ® trois jours avant le debut de l’atteinte cutanee. Le bilan biologique montrait une polynucleose neutrophile a 15 000 elements/mm 3 et une CRP a 172 mg/L sans autre anomalie. Les hemocultures etaient steriles. Les serologies pour la rougeole, le VIH, les hepatites B et C, l’EBV, le parvovirus B19, le CMV et la syphilis etaient negatives, de meme que la recherche de Mycoplasma pneumoniae dans la gorge. Une biopsie cutanee montrait un infiltrat inflammatoire dermique comportant des lymphocytes et des polynucleaires neutrophiles ainsi qu’une petite pustule intra-epidermique superficielle. Une culture et une technique de MALDI TOF d’un prelevement de gorge etait realisee et identifiait Arcanobacterium haemolyticum . L’evolution etait favorable en une semaine sous erythromycine orale. Discussion Arcanobacterium haemolyticum est un bacille gram positif pouvant etre a l’origine d’une pharyngite associee a un exantheme, essentiellement chez des sujets jeunes. La presentation de cet exantheme est particuliere par sa localisation acrale et un caractere considere parfois comme pseudo-urticarien, en fait ici maculopapuleux fixe. Le blanchiment central des lesions, deja decrit dans la litterature au cours de cette affection, pourrait permettre de le differencier des autres causes d’exantheme. A notre connaissance, la presence d’une pustule intra-epidermique, qui aurait pu faire discuter une pustulose exanthematique et egarer le diagnostic, n’a jamais ete rapportee. Des cas d’infections viscerales severes profondes et de septicemies associees ont ete rapportes. Cette entite est probablement sous diagnostiquee car seuls des examens bacteriologiques sur frottis de gorge permettent de mettre A. haemolyticum en evidence. Le traitement de premiere intention repose sur les macrolides, en particulier l’erythromycine orale. Conclusion Nous souhaitons attirer l’attention sur une cause non rare mais meconnue d’exantheme febrile du sujet jeune. L’infection a A. haemolyticum fait partie des diagnostics differentiels a evoquer devant un exantheme du sujet jeune. Le germe peut etre identifie sur un prelevement de gorge, geste qui devrait etre realise largement devant un tel tableau clinique.

Cadmium Zinc Telluride (CZT) is the detector material of choice for the detection of X-rays in the 10 keV-1MeV energy band with excellent spatial and energy resolutions and without cryogenic cooling. In this contribution, we report on recent results of the CZT detector development program and several astrophysical experiments which make use of CZT detectors. In the first part of the paper, we discuss the performance of pixel and cross-strip CZT detectors read out with an ASIC developed at the Brookhaven National Laboratory. Our pixel detectors achieve some of the best energy resolutions reported in the literature. Cross-strip detectors are found to give an inferior performance and we investigate the reason for this performance difference. We also present results from a precision measurement of the effect of a steering grid on multi-pixel events obtained with a 200 micrometer collimator. In the second part of the paper, we describe the design and performance of the hard X-ray polarimeter X-Calibur. The polarimeter uses a 14 cm long scintillator scatterer, surrounded by an assembly of 32 2-5 mm thick CZT detectors. We discuss the sensitivity of the polarimeter to measure the linear polarization of 10 keV-80 keV X-rays on short and long balloon flights and results from testing the polarimeter in the laboratory.

CdZnTe, commonly known as CZT is the material of paramount importance for hard X-ray and gamma ray spectroscopy and imaging applications at room temperature. Over the years, the quality of CZT crystals and its charge transport properties has improved significantly making it an attractive detector material especially for homeland security applications. The applications for homeland security demand large and thick detectors to provide a sufficient stopping power for fast detection of high energy gamma photons. In this present report we have grown two inch diameter CZT by Traveling heater method (THM) technique. The as-grown crystals were characterized through photoluminescence (PL) mapping for composition uniformity, growth interface study, Te precipitations/inclusions studies. In order to evaluate our as-grown samples, charge transport characteristics have been studied for thick samples up to ~16mm thick. It has been demonstrated that by controlling the growth interface, visualization of large and thick (~16mm thick) detectors with fairly good response is possible from as-grown CZT detectors grown by THM technique.

Synthetic CdZnTe or “CZT” crystals are highly suitable for γ-spectrometers operating at the room temperature. Secondary phases (SP) in CZT are known to inhibit detector performance, particularly when they are present in large numbers or dimensions. These SP may exist as voids or composites of non-cubic phase metallic Te layers with bodies of polycrystalline and amorphous CZT material and voids. Defects associated with crystal twining may also influence detector performance in CZT. Using transmission electron microscopy, we identify two types of defects that are on the nano scale. The first defect consists of 40 nm diameter metallic Pd/Te bodies on the grain boundaries of Te-rich composites. Although the nano-Pd/Te bodies around these composites may be unique to the growth source of this CZT material, noble metal impurities like these may contribute to SP formation in CZT. The second defect type consists of atom-scale grain boundary dislocations. Specifically, these involve inclined “finite-sized” planar defects or interfaces between layers of atoms that are associated with twins. Finite-sized twins may be responsible for the subtle but observable striations that can be seen with optical birefringence imaging and synchrotron X-ray topographic imaging.

In this present work we report the growth of Cd0.9Zn0.1Te doped with In by a modified THM technique. It has been demonstrated that by controlling the microscopically flat growth interface, the size distribution and concentration of Te inclusions can be drastically reduced in the as-grown ingots. This results in as-grown detector-grade CZT by the THM technique. The three-dimensional size distribution and concentrations of Te inclusions/precipitations were studied. The size distributions of the Te precipitations/inclusions were observed to be below the 10-μm range with the total concentration less than 105 cm-3. The relatively low value of Te inclusions/precipitations results in excellent charge transport properties of our as-grown samples. The (μτ)e values for different as-grown samples varied between 6-20 x10-3 cm2/V. The as-grown samples also showed fairly good detector response with resolution of ∼1.5%, 2.7% and about 3.8% at 662 keV for quasi-hemispherical geometry for detector volumes of 0.18 cm3, 1 cm3 and 4.2 cm3, respectively.

The Czochralski pulling process is the most valuable and cost efficient method for producing large oriented single crystals of the group IV and III-V semiconductors. However, there have been only a small number of reported attempts to use the Czochralski process for growing the wide bandgap compound semiconductors, needed for the room temperature operated gamma-ray detectors. The main difficulty is in the low chemical stability and high vapor pressure of the group II, V and VI elements, leading to off-stoichiometric composition, and various related defects. Among the heavy metal halides, indium iodide and indium bromide present an interesting exception. InI has a high molecular disassociation energy and a low vapor pressure, allowing for Czochralski pulling. We will describe the procedures used and the results obtained by Czochralski growth and characterization of indium iodide and the related ternary compounds that appear to be quite encouraging.

Europium-doped strontium iodide (SrI 2 :Eu) crystals are reported to be high light yield scintillator materials with good energy resolution, the best energy resolution of SrI 2 :Eu at 662 keV having reached 2.6%. To improve the crystals growth quality and to protect the crystals from hydration, it is practical to distinguish the pure crystals from impurity and structural defects by Raman spectroscopy. In this report, SrI 2 :Eu crystals grown from the vertical Bridgman method have been characterized with the polarized Raman spectroscopy. Orientations of the crystals were determined with the spectroscopy assisted with the polarized optical microscopy. The crystals are highly hygroscopic, the intensity of new peak at 87 cm−1 associated with SrI 3 − anions continues to increase with time even the samples are kept in mineral oil or encapsulated in parylene. Micro-Raman mapping on the distributions of SrI 3 − anions in SrI 2 crystals stored in mineral oil are reported.

We are developing new scintillator materials that offer potential for high resolution gamma ray spectroscopy at low cost. Single crystal SrI 2 (Eu) offers ∼3% resolution at 662 keV, in sizes of ∼1 in3. We have developed ceramics processing technology allowing us to achieve cubic inch scale transparent ceramic scintillators offering gamma spectroscopy performance superior to NaI(Tl). Our bismuth-loaded plastic scintillator demonstrates energy resolution of ∼8% at 662 keV, for samples of ∼0.5 cm3.

Cadmium Zinc Telluride (CZT) continues to progress in quality and cost as a material for the detection of hard X-ray and gamma-ray photons with excellent spatial and energy resolutions. We are developing large-volume (0.5×3.9×3.9 cm 3 ) cross-strip CZT detectors with the objective to combine the excellent performance achieved so far only with pixelated CZT detectors with a reduced number of readout channels. In this contribution, we discuss the spectroscopic performance of large volume CZT detectors from the company Orbotech when contacted as pixelated detectors. Subsequently, we present results obtained when the same substrates where contacted with cross-strip contacts. Finally, we use the results from a simulation study to discuss the optimization of the design of the strip contacts and the readout electronics.

We report on the continued development and testing of unique types of Cadmium Zinc Telluride (CZT) detectors.Using large volume (10 × 20 × 20 mm 3 ) CZT crystals, we contact variou s dual anodeŽ detector designs. Weincorporate a segmented cathode with “ve regions so that the charge on all seven contacts can be used todetermine the energy and the 3-D interaction location of detected X-ray and gamma-ray photons. We describethe status of the detector development program, emphasize strengths and weaknesses of the dierent contactcon“gurations, and discuss possible applications of Dual Anode Detectors in radiation detection applications.Keywords: CZT, X-ray Detector , Contact Geometry 1. INTRODUCTION The high average atomic number ( 50) and room temperature operation of Cadmium Zinc Telluride (CZT)detectors make them desirable for Homeland Security a pplications where high eciency of detecting nuclearartifacts is required, such as a stand o detector at a border crossing. We currently are working to developlarge-volume CZT detectors with few re adout channels by exploring novel contact designs. Such designs presentcertain advantages while avoiding the complications, limitations, and requirements of using the standard contactpatterns.The most common CZT detector designs in use today employ either pixel contacts or a coplanar grid (CPG)for the anode.

The introduction of large single crystal and high performance CdZnTe (CZT) grown by the traveling heater method (THM) in 2006 has defied conventional myths about the capability of this crystal growth method with respect to the production of spectroscopic grade CZT and its commercialization prospect in medical imaging application. Since then, a lot of progresses have been made, both in the crystal growth and the devices sides. This paper focuses on the development of THM CZT in recent years. Crystalline defects which challenge the thickness scalability of large volume CZT detectors along with efforts and achievements in overcoming these challenges are discussed. Advances in THM CZT crystal growth include 100mm diameter ingot and state-of-the-art device fabrication will also be presented.

In an effort to optimize the spectroscopic performance of large volume Cadmium Zinc Telluride (CZT) radiation detectors grown by the Traveling Heater Method (THM), especially for higher energy gamma detection applications, bulk material and pixellated detector performance of THM CZT crystals at 15mm-thick and 10mm-thick were compared to that at 5mm-thick. We demonstrate that the outstanding performance of monolithic pixellated THM CZT detectors was thickness-scalable. For the same monolithic 20×20 mm2 “Compton Camera” pixellated detector configuration, detector performance can certainly be significantly improved as the thickness of the detector increases from 5mm to 10mm and thicker as demonstrated via both 57Co 122 keV and 137Cs 662 keV spectral responses. Depth of interaction information obtained from 3D depth sensing measurement system, IR microscopy and x-ray topography were used to study the correlation between structural quality and detector performance. Additional material characterizations and detector performances of various sizes and configurations were also presented and discussed.

The growth and scintillating properties of undoped and Eu2+ doped Strontium Iodide indicate excellent potential for gamma ray spectroscopy. Energy resolution at 662 keV was found to be as good as 2.7% at 662 keV. The effect of purification by zone refining was also studied and crystal growth of SrI2 by the Bridgman technique was found to be less subject to cracking compared to the growth of lanthanum halide scintillators.

We report the case of a young smoker woman who developed a severe acrosyndrome of rapid onset, involving both hands except the thumbs. The angiography showed digital arteritis. Antinuclear antibodies were present at high level. Three months later, a large B cell lymphoma was diagnosed. Complete remission was achieved, but the acrosyndrome persisted with only partial improvement. The antinuclear antibodies disappeared. The paraneoplastic nature of the acrosyndrome is discussed.

The detector material Cadmium Zinc Telluride (CZT), known for its high resolution over a broad energy range, is produced mainly by two methods: the Modified High-Pressure Bridgman (MHB) and the High-Pressure Bridgman (HPB) process. This study is based on MHB CZT substrates from the company Orbotech Medical Solutions Ltd. with a detector size of 2.0x2.0x0.5 cm^3, 8x8 pixels and a pitch of 2.46 mm. Former studies have emphasized only on the cathode material showing that high-work-function improve the energy resolution at lower energies. Therfore, we studied the influence of the anode material while keeping the cathode material constant. We used four different materials: Indium, Titanium, Chromium and Gold with work-functions between 4.1 eV and 5.1 eV. The low work-function materials Indium and Titanium achieved the best performance with energy resolutions: 2.0 keV (at 59 keV) and 1.9 keV (at 122 keV) for Titanium; 2.1 keV (at 59 keV) and 2.9 keV (at 122 keV) for Indium. These detectors are very competitive compared with the more expensive ones based on HPB material if one takes the large pixel pitch of 2.46 mm into account. We present a detailed comparison of our detector response with 3-D simulations, from which we determined the mobility-lifetime-products for electrons and holes. Finally, we evaluated the temperature dependency of the detector performance and mobility-lifetime-products, which is important for many applications. With decreasing temperature down to -30C the breakdown voltage increases and the electron mobility-lifetime-product decreases by about 30% over a range from 20C to -30C. This causes the energy resolution to deteriorate, but the concomitantly increasing breakdown voltage makes it possible to increase the applied bias voltage and restore the full performance., Accepted for publication in Astroparticle Physics, 25 pages, 13 figures

The performance of current long-drift-length Cadmium Zinc Telluride (CZT) detectors principally is determined by the material's quality. Hence, the material's limitations must be better understood and potential solutions identified to grow CZT crystals with the required qualities. Our efforts have focused on developing novel techniques and testing methods that will allow us to explore the correlations between the crystal's defects and the detector's properties. Local stoichiometric variations and other local disordering make it very hard to systematically correlate performance and material defects on a macroscopic scale. Therefore, to delineate the factors limiting the energy resolution of CZT detectors, we directed our efforts towards micron-scale material characterization and assessments of the detectors using the National Synchrotron Light Source (NSLS). The NSLS offers us a highly collimated high-intensity X-ray beam that we employed to undertake detector-performance mapping, and to investigate the association between microscopic defects and fluctuations in collected charge. In this paper, we illustrate our techniques and results.

High quality detector grade GaSe and GaTe single crystals have been grown by a modified vertical Bridgman technique using high purity Ga (7N) and in-house zone refined (ZR) precursor materials (Se and Te). A state-of-the-art computer model, MASTRAPP, is used to model heat and mass transfer in the Bridgman growth system and to predict the stress distribution in the as-grown crystals. The model accounts for heat transfer in the multiphase system, convection in the melt, and interface dynamics. The crystals harvested from ingots of 8-10 cm length and 2.5 cm diameter, have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy, low temperature photoluminescence (PL), atomic force microscopy (AFM), and optical absorption/transmission measurements. Single element devices up to 1 cm 2 in area have been fabricated from the crystals and tested as radiation detectors by measuring current-voltage (I-V) characteristics and pulse height spectra using 241 Am source. The crystals have shown high promise as nuclear detectors with their high dark resistivity (≥10 9 Ω . cm), good charge transport properties (μτ e ~ 1.4x10 -5 cm 2 /V and μτ h ~ 1.5x10 -5 cm 2 /V), and relatively good energy resolution (~4% energy resolution at 60 keV). Details of numerical modeling and simulation, detector fabrication, and testing using a 241 Am energy source (60 keV) is presented in this paper.

Upon examination we have concluded that none of the alarms indicate the presence of a real threat. A brief history and results from our examination of the NYCT ASP occupancy data sets dated from 2007-05-14 19:11:07 to 2007-06-20 15:46:15 are presented in this letter report. When the ASP data collection campaign at NYCT was completed, rather than being shut down, the Canberra ASP annunciator box was unplugged leaving the data acquisition system running. By the time it was discovered that the ASP was still acquiring data about 15,000 occupancies had been recorded. Among these were about 500 alarms (classified by the ASP analysis system as either Threat Alarms or Suspect Alarms). At your request, these alarms have been investigated. Our conclusion is that none of the alarm data sets indicate the presence of a real threat (within statistics). The data sets (ICD1 and ICD2 files with concurrent JPEG pictures) were delivered to LLNL on a removable hard drive labeled FOUO. The contents of the data disk amounted to 53.39 GB of data requiring over two days for the standard LLNL virus checking software to scan before work could really get started. Our first step was to walk through the directorymore » structure of the disk and create a database of occupancies. For each occupancy, the database was populated with the occupancy date and time, occupancy number, file path to the ICD1 data and the alarm ('No Alarm', 'Suspect Alarm' or 'Threat Alarm') from the ICD2 file along with some other incidental data. In an attempt to get a global understanding of what was going on, we investigated the occupancy information. The occupancy date/time and alarm type were binned into one-hour counts. These data are shown in Figures 1 and 2.« less

Gamma ray spectroscopy for remote sensing applications requires a high sensitivity that can be achieved by a combination of high efficiency and high energy resolution for high energy gamma rays (up to 1 MeV) . While cryogenic germanium detectors or LaBr3:Ce3+ scintillators could in principle satisfy the requirements of many such applications, the search for compact, portable systems that do not require cooling or the use of photomultiplier tubes are still underway. State-of-the-art CdZnTe spectrometers having an energy resolution exceeding 1% have been recently demonstrated, however they have a typical volume that is less than 1 cm3. Large volume (greater than 3 cm3) CdZnTe spectrometers with an energy resolution that is better than 3% are not yet commercially available, although the size of large single crystals that would satisfy the volume requirement can now be grown by various companies with reasonable yield. In this study we have investigated the feasibility of using commercially available large (1-6 cm3) detector grade CdZnTe single crystals to fabricate co-planar gamma spectrometers with a targeted performance that exceeds 3% energy resolution at 662 keV. The fabrication of optimal performance coplanar detectors requires a custom design that might vary for each crystal growth method. Besides the knowledge of the average values of charge carrier concentrations, mobilities and trapping times the physics-based model requires the knowledge of bulk nonuniformities and their effects on local variations in the electric field and electron mobility-trapping-time product. All crystals investigated had tellurium, as second phase. A new type of material inhomogeneity, and its influence on detector's performance, became apparent only in large volume crystals and will be reported.

The layered III-VI semiconductor Gallium Telluride has potential for room temperature gamma ray spectroscopy applications due to its band gap of 1.67 eV, and average atomic number of 45 : 31 (Ga) and 52 (Te). The physical properties of GaTe are highly anisotropic due to covalent bonding within the layer and van der Waals bonding between layers. This work reports the results of surface and bulk processing, surface characterization, and electrical characterization of diodes formed on both the laminar and non-laminar GaTe surfaces. Alpha detection measurements were also performed.

Introduction Les patients atteints de drepanocytose sont susceptibles d’etre transfuses au cours de leur parcours medical. Les transfusions repetees pouvant occasionner une surcharge en fer, nous avons voulu en evaluer la prevalence au sein d’une population de patients suivis en hematologie et en medecine interne aux hopitaux universitaires de Strasbourg. Resultats Les dossiers de 50 patients ont ete identifies par le PMSI depuis juillet 2008. Six patients ont ete exclus, 1 qui avait egalement une leucemie aigue et 5 qui ne presentaient pas de syndrome drepanocytaire majeur. L’âge moyen des 44 patients retenus est de 32 ans (15–64 ans), le sex-ratio F/M est de 2,4. Vingt-six patients etaient homozygotes (SS), 10 patients doubles heterozygotes SC et 6 patients doubles heterozygotes Sbeta thalassemie (Sbeta). Deux autres patients etaient SS avec un trait alpha thalassemique. Une surcharge en fer, definie par une ferritine superieure a 1000 ng/mL a distance de toute crise hemolytique ou transfusion, etait notee pour 9 patients dont 6 etaient SS et 3 Sbeta (1040 a 8940 ng/mL). Il n’y avait pas de ferritine dosee dans des conditions adequates pour 6 patients. Parmi les 9 patients avec ferritine superieure a 1000, 2 qui avaient le taux de ferritine le plus eleve (2270 et 8940 ng/mL) ont eu une IRM avec confirmation de la surcharge en fer hepatique (270 et 350 μmol/g). 5 autres patients (avec ferritine non dosee ou inferieure a 1000 ng/mL) ont eu une IRM hepatique pour une autre raison, avec des sequences qui permettaient de rechercher a posteriori une surcharge sans la quantifier, et ainsi, un patient, chez qui nous n’avons pas trouve de ferritine dosee dans les conditions requises, a ete identifie comme porteur d’une surcharge martiale hepatique. Parmi les 9 (ferritine) + 1 (IRM) patients surcharges en fer, tous avaient ete transfuses, 5 etaient consideres comme l’ayant ete beaucoup, et seuls 2 etaient traites par chelateurs du fer. Parmi les 6 patients Sbeta, 3 patients etaient surcharges en fer, et avaient ete beaucoup transfuses dans l’enfance. Aucun des 10 patients SC n’etait surcharge en fer. Concernant les antecedents transfusionnels, 35 patients avaient ete transfuses au cours de leur suivi, l’information etait manquante pour 5 d’entre eux (souvent suivis a l’etranger auparavant), 4 patients n’avaient jamais ete transfuses (tous SC). Discussion Bien qu’elle soit reputee moins frequente que dans les thalassemies, la surcharge en fer est une complication de la prise en charge de la drepanocytose [1] : la prevalence va de 8 % [1] a 22 % sur une petite etude autopsique [2] des patients, et elle serait en cause dans 7 a 45 % des deces. Dans notre serie, si l’on se base sur l’hyperferritinemie et/ou sur l’IRM hepatique, elle n’atteint pas moins de 23 % des patients. Il s’agit bien-sur d’une etude retrospective, sur dossier et sur un petit effectif, mais les conditions strictes de selection des dosages de ferritine font que le risque d’erreur d’evaluation de la prevalence dans notre population est faible. Dans notre etude, les patients SC, moins transfuses, sont moins exposes a la surcharge, par contre, la moitie des patients Sbeta sont surcharges, sans que cela n’atteigne une significativite statistique. Seuls 2 patients sur les 10 surcharges sont traites dans notre serie. Conclusion Notre etude souligne la necessite d’informer les patients sur certains aspects de leur prise en charge (ici la recherche et le traitement d’une surcharge en fer), au cours de leur hospitalisation pour complication de la maladie, certains patients n’etant pas suivis en dehors des hospitalisations. Elle permet de rappeler que les indications de transfusions doivent etre soigneusement pesees chez ces patients, une anemie meme marquee n’etant pas a elle seule une indication de transfusion et les consequences en termes de surcharge mais egalement d’allo-immunisation etant loin d’etre negligeables. La pratique d’echanges transfusionnels, automatises ou non, permet de limiter la surcharge en fer. Il ne faut pas oublier de debuter une chelation au-dela de 20 culots administres, des que la ferritine est au-dela de 1000 ng/mL ou la surcharge en fer hepatique a l’IRM superieure a 150 μmol/g [3] .

The paper deals with the optimal compensation of distribution networks, approached and solved as a nonlinear optimisation problem. The first part presents the problem statement and the calculation of the power flow for a radial distribution network under certain operating conditions. The state variables are calculated by solving a 3n order, nonlinear equation system, using a Newton type method, where n is the number of the network's sections. The presented example emphasises the method's mechanism and its advantages

The paper deals with the optimal compensation of distribution networks, approached and solved as a nonlinear optimisation problem. The first part presented the problem statement and the calculation of the power flow for a radial distribution network under certain operating conditions. The second part formulates and solves the optimisation problem - a constrained nonlinear programming one. The conjugated gradient method (the Fletcher-Reeves algorithm) is used, together with the penalty function method and with the Lagrange multipliers method. The presented example emphasises the method's mechanism and its advantages

Cadmium Zinc Telluride (CZT) detectors are having a major impact on the field of hard X-ray astronomy. Without the need for cryogenic cooling they achieve good spatial and energy resolutions over the broad energy range from 10 keV to 600 keV. In this paper, we briefly review the historical development of detectors used in X-ray astronomy. Subsequently, we present an evaluation of CZT detectors from the company Imarad. The standard 2x2x0.5 cm detectors, contacted with 8x8 In pixels and an In cathode, exhibit FWHM energy resolutions of 7 keV at 59 keV, and 10 keV at 662 keV. A direct measurement of the 662 keV photopeak efficiency gives 67%. We have started a detailed study of the performance of Imarad detectors depending on surface preparation, contact materials, contact deposition, post-deposition detector annealing, and detector passivation techniques. We present first results from contacting detectors with Cr, Ag, Au, and Pt., Invited Contribution to the 49th International Symposium on Optical Science and Technology (SPIE), August 2004, Denver, CO, SPIE, 49, 5540, 13.01. (2004)

Recent progress has been made in the development of the Modified Vertical Bridgman (MVB) technique for the growths of 3-inch diameter CZT crystals for fabrication of x-ray and gamma-ray detectors to operate at room temperature. 40% and 80% of the ingots have the single crystal volumes over 300cm 3 and 100 cm 3 per ingot respectively. Defects (such as Cd-vacancies, Indium dopants and purity) in CZT have been systematically studied. Detectors fabricated from these CZT ingots showed sharp energy resolution and good uniformity.

Single crystals of semiconductor-grade lithium indium selenide (LiInSe2) were grown using the vertical Bridgman method. The orthorhombic structure of the materials was verified using powder x-ray diffraction. The room temperature band gap of the crystal was found to be 2.85 eV using optical absorption measurements. Resistivity of LiInSe2, obtained using current-voltage measurements, has semiconducting nature (decreases with increasing temperature) and is in order of 1010 Ω·cm. Photoconductivity measurement showed the photocurrent peak at 445 nm. Nuclear radiation devices were fabricated, and alpha particle detection was observed, suggesting that this material could be a candidate for neutron detection applications.

We report variations in the currents of CdZnTe semiconductor crystals during exposure to a series of light emitting diodes of various wavelengths ranging from 470 to 950 nm. The changes in the steady-state current of one CdZnTe crystal with and without illumination along with the time dependence of the illumination effects are discussed. Analysis of the de-trapping and transient bulk currents during and after optical excitation yield insight into the behaviour of charge traps within the crystal. Similar behaviour is observed for illumination of a second CdZnTe crystal suggesting that the overall illumination effects are not crystal dependent.

Adult female citrus red mites, Panonychus citri, infected with a nonoccluded virus and feeding on the surface of green lemons, deposited virus that was infective through 28 days to other mites feeding on the same surface for 24 hr. Incidence of infection diminished from a high of 87% 2 days after removal of vector mites to 5% after 28 days. Inocula prepared from dead intact virus-infected mites held at room temperature (21–27°C) were infective up to 28 days when sprayed on colonies of mites on lemons.