Experiments with a cooled antiproton beam at the future accelerator facility at the Gesellschaft fur Schwer Ionenforschung, Darmstadt, Germany, will be performed with the 4/spl pi/ detector proton ...antiproton at Darmstadt comprising a high-resolution, compact, and fast homogeneous electromagnetic calorimeter to detect photons between 10 MeV and 10 GeV energy inside a superconducting solenoid (2 T). PbWO/sub 4/ (PWO) crystals, readout with large size avalanche photodiodes, represent an envisaged detector concept. The first results of a new generation of significantly improved PWO crystals, operated at different temperatures, are presented and discussed in detail. The requirements for the photo sensor are outlined based on first test measurements. A new fast hybrid photomultiplier (PLANACON 85001-501, BURLE) with channel plate amplification was investigated for comparison.
This report presents results on the significant improvement of GAGG:Ce based scintillation detector performance with temperature decrease. When temperature of a PMT based detector is lowered to ...−45 °C, its amplitude response at registration of γ-quanta is improved by 30%; FHHM was found to be better up to factor of 0.85, whereas scintillation kinetics become even faster in crystals co-doped with magnesium and magnesium and titanium. All this opens an opportunity for a wide application of GAGG scintillation detectors, particularly in a combination with SiPM photo-sensors, which signal-to-noise ratio would also improve with temperature decrease.
The development of novel scintillators for ionizing radiation detectors is still playing a significant role in high-energy physics, medical and homeland security applications. New detector concepts ...require a unique combination of the material properties like rising and decay times, light output and in the case of collider experiments the radiation hardness. cerium doped garnet type scintillation materials have been intensively developed in the last years. Among them, Y 3 Al 5 O 12 (YAG), Lu 3 Al 5 O 12 (LuAG) and Gd 3 Al 2 Ga 3 O 12 (GAGG) with high radiation hardness recognized for both gamma- and proton irradiation, were found to be the most promising materials. Many modern detector systems based on scintillation materials require high-count rates. This involves the use of bright scintillators with fast rise and decay times in combination with modern ultra-fast photodetectors such as SiPMs. A possible solution for such kind of applications is a family of lutetium-yttrium oxyorthosilicates (Lu 2(1-x) Y 2x SiO5, LSO, LYSO, YSO). Here we report on the characterization of different types of garnets with various dopants and in shapes of pixels and bulk and on the study of properties of LSO, LYSO, YSO solely doped by Ce as well LYSO materials with Ca and Mg co-doping from different producers.
One of the principal goals of glycoprotein research is to correlate glycan structure and function. Such correlation is necessary in order for one to understand the mechanisms whereby glycoprotein ...structure elaborates the functions of myriad proteins. The accurate comparison of glycoforms and quantification of glycosites are essential steps in this direction. Mass spectrometry has emerged as a powerful analytical technique in the field of glycoprotein characterization. Its sensitivity, high dynamic range, and mass accuracy provide both quantitative and sequence/structural information. As part of the 2012 ABRF Glycoprotein Research Group study, we explored the use of mass spectrometry and ancillary methodologies to characterize the glycoforms of two sources of human prostate specific antigen (PSA). PSA is used as a tumor marker for prostate cancer, with increasing blood levels used to distinguish between normal and cancer states. The glycans on PSA are believed to be biantennary N-linked, and it has been observed that prostate cancer tissues and cell lines contain more antennae than their benign counterparts. Thus, the ability to quantify differences in glycosylation associated with cancer has the potential to positively impact the use of PSA as a biomarker. We studied standard peptide-based proteomics/glycomics methodologies, including LC-MS/MS for peptide/glycopeptide sequencing and label-free approaches for differential quantification. We performed an interlaboratory study to determine the ability of different laboratories to correctly characterize the differences between glycoforms from two different sources using mass spectrometry methods. We used clustering analysis and ancillary statistical data treatment on the data sets submitted by participating laboratories to obtain a consensus of the glycoforms and abundances. The results demonstrate the relative strengths and weaknesses of top-down glycoproteomics, bottom-up glycoproteomics, and glycomics methods.
The universal field oriented controller De Doncker, R.W.; Novotny, D.W.
IEEE transactions on industry applications,
01/1994, Letnik:
30, Številka:
1
Journal Article
Recenzirano
This paper synthesizes and develops a universal field oriented (UFO) controller for induction machines. The UFO controller decouples flux and torque in an arbitrary flux reference frame. Due to its ...high degree of generality the UFO controller lends itself to be fully compatible with all existing field oriented controllers, indirect as well as direct field orientation. As a consequence, the digital implementation of the UFO scheme is identical for all induction motor drives enabling the usage of identical hardware and software. Examples of UFO control block diagrams for different field oriented controllers are presented. The execution time of the UFO algorithm is compared with the classical rotor flux field orientation method when using a high speed digital signal processor. Further, this paper indicates that the flexibility of changing the flux reference frame can extend the stability region of the drive especially at high speed during flux weakening. Detuning problems in field orientation are handled in an optimal manner for each field oriented controller by proper selection of the model of the induction machine and its reference frame.< >
The PANDA experiment will be part of the future Facility for Antiproton and Ion Research (FAIR) and aims for the study of strong interaction within the charm sector via antiproton proton collisions ...up to antiproton momenta of 15 GeV/c. Reflecting the variety of the physics program the PANDA detector is designed as a multi-purpose detector able to perform tracking, calorimetry and particle identification with nearly complete coverage of the solid angle. The Electromagnetic Calorimeter (EMC) contained inside its Target Spectrometer is based on cooled PbWO4 scintillator crystals. In order to ensure an excellent performance throughout the large dynamic range of photon/electron energies ranging from a few MeV up to 15 GeV an extensive prototyping phase is mandatory. This contribution describes the measured response of the EMC barrel part prototype PROTO60 at the largest design energy to secondary beams provided by the SPS at CERN. In addition to PROTO60 a tracking station was deployed, providing precise position information of the 15 GeV/c positrons. For calibration purposes a 150 GeV/c muon beam and cosmic radiation, in combination with estimations from GEANT4 simulations were used. The obtained performance concerning energy, position and time information is presented.
High-quality PWO crystals for the PANDA-EMC Novotny, R W; Bremer, D; Dormenev, V ...
Journal of physics. Conference series,
01/2011, Letnik:
293, Številka:
1
Journal Article
Recenzirano
Odprti dostop
The paper provides a status report on the crystal production and quality control of a major part of the PbWO4 crystals for the PANDA-EMC. The results confirm the excellent performance of the new ...generation of PWO-II. The mechanism of stimulated recovery provides an additional tool to recover radiation damage at room and low temperatures by applying an external infrared light source. Even on-line recovery can be considered if the photo sensor is insensitive in that particular wavelength region.
For the first time, full size lead tungstate crystals of different suppliers, quality and dopant concentration have been irradiated with gamma-rays at low temperatures down to -25degC at IHEP ...Protvino. In contrast to the behavior at room temperature, increased damage and extremely slow recovery processes have been observed. These first results are discussed in the light of several very different interpretations. Further more sensitive measurements are under preparation. The outcome will have a strong impact on the presently assembled ALICE-PHOS detector and the design of the EM calorimeter of PANDA at the future FAIR facility.
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