scholarly journals Influence of a Surface Finishing Method on Light Collection Behaviour of PWO Scintillator Crystals

Photonics ◽  
2018 ◽  
Vol 5 (4) ◽  
pp. 47 ◽  
Author(s):  
Daniele Rinaldi ◽  
Luigi Montalto ◽  
Michel Lebeau ◽  
Paolo Mengucci
Keyword(s):  
High Energy Physics ◽  
Collection Efficiency ◽  
Removal Rate ◽  
Light Yield ◽  
Grazing Incidence ◽  
Structural Condition ◽  
High Energy ◽  
Production Performance ◽  
Surface Finishing ◽  
Light Collection

In the field of scintillators, high scintillation and light production performance require high-quality crystals. Although the composition and structure of crystals are fundamental in this direction, their ultimate optical performance is strongly dependent on the surface finishing treatment. This paper compares two surface finishing methods in terms of the final structural condition of the surface and the relative light yield performances. The first polishing method is the conventional “Mechanical Diamond Polishing” (MDP) technique. The second polishing technique is a method applied in the electronics industry which is envisaged for finishing the surface treatment of scintillator crystals. This method, named “Chemical Mechanical Polishing” (CMP), is efficient in terms of the cost and material removal rate and is expected to produce low perturbed surface layers, with a possible improvement of the internal reflectivity and, in turn, the light collection efficiency. The two methods have been applied to a lead tungstate PbWO4 (PWO) single crystal due to the wide diffusion of this material in high energy physics (CERN, PANDA project) and diagnostic medical applications. The light yield (LY) values of both the MDP and CMP treated crystals were measured by using the facilities at CERN while their surface structure was investigated by Scanning Electron Microscopy (SEM) and Grazing Incidence X-ray Diffraction (GID). We present here the corresponding optical results and their relationship with the processing conditions and subsurface structure.

Status of Cerium Fluoride Performances

1994 ◽  
Vol 348 ◽  
Author(s):  
E. Auffray ◽  
I. Dafinei ◽  
P. Lecoq ◽  
M. Schneegans
Keyword(s):  
Decay Time ◽  
High Energy Physics ◽  
Light Yield ◽  
High Energy ◽  
Radiation Hardness ◽  
Cerium Fluoride ◽  
The World ◽  
Electromagnetic Calorimeters ◽  
Physics Experiments ◽  
Energy Physics

ABSTRACTCerium fluoride offers a reasonable compromise between parameters like the density, the light yield, the scintillation characteristics (particularly the decay time) and the radiation hardness, and is considered today as the best candidate for large electromagnetic calorimeters in future High Energy Physics experiments. Details on the performances of large crystals produced by different manufacturers all over the world and measured by the Crystal Clear collaboration will be shown and the usefulness of a good collaboration between the industry and the users will be highlighted by some examples on the light yield and radiation hardness improvement.

scholarly journals Quality Control and Structural Assessment of Anisotropic Scintillating Crystals

Crystals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 376 ◽  
Author(s):  
Luigi Montalto ◽  
Pier Natali ◽  
Lorenzo Scalise ◽  
Nicola Paone ◽  
Fabrizio Davì ◽  
...  
Keyword(s):  
Residual Stress ◽  
High Energy Physics ◽  
Radiation Detectors ◽  
Structural Condition ◽  
High Energy ◽  
Complete Characterization ◽  
Non Invasive ◽  
Light Production ◽  
Core Elements ◽  
Stress States

Nowadays, radiation detectors based on scintillating crystals are used in many different fields of science like medicine, aerospace, high-energy physics, and security. The scintillating crystals are the core elements of these devices; by converting high-energy radiation into visible photons, they produce optical signals that can be detected and analyzed. Structural and surface conditions, defects, and residual stress states play a crucial role in their operating performance in terms of light production, transport, and extraction. Industrial production of such crystalline materials is a complex process that requires sensing, in-line and off-line, for material characterization and process control to properly tune the production parameters. Indeed, the scintillators’ quality must be accurately assessed during their manufacture in order to prevent malfunction and failures at each level of the chain, optimizing the production and utilization costs. This paper presents an overview of the techniques used, at various stages, across the crystal production process, to assess the quality and structural condition of anisotropic scintillating crystals. Different inspection techniques (XRD, SEM, EDX, and TEM) and the non-invasive photoelasticity-based methods for residual stress detection, such as laser conoscopy and sphenoscopy, are presented. The use of XRD, SEM, EDX, and TEM analytical methods offers detailed structural and morphological information. Conoscopy and sphenoscopy offer the advantages of fast and non-invasive measurement suitable for the inspection of the whole crystal quality. These techniques, based on different measurement methods and models, provide different information that can be cross-correlated to obtain a complete characterization of the scintillating crystals. Inspection methods will be analyzed and compared to the present state of the art.

scholarly journals Inorganic, Organic, and Perovskite Halides with Nanotechnology for High–Light Yield X- and γ-ray Scintillators

Crystals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 88 ◽  
Author(s):  
Francesco Maddalena ◽  
Liliana Tjahjana ◽  
Aozhen Xie ◽  
Arramel ◽  
Shuwen Zeng ◽  
...  
Keyword(s):  
High Energy Physics ◽  
Low Cost ◽  
Light Yield ◽  
Fast Response ◽  
High Energy ◽  
High Light ◽  
Scintillation Light ◽  
High Light Yield ◽  
Halide Perovskites ◽  
Lead Halide

Trends in scintillators that are used in many applications, such as medical imaging, security, oil-logging, high energy physics and non-destructive inspections are reviewed. First, we address traditional inorganic and organic scintillators with respect of limitation in the scintillation light yields and lifetimes. The combination of high–light yield and fast response can be found in Ce 3 + , Pr 3 + and Nd 3 + lanthanide-doped scintillators while the maximum light yield conversion of 100,000 photons/MeV can be found in Eu 3 + doped SrI 2 . However, the fabrication of those lanthanide-doped scintillators is inefficient and expensive as it requires high-temperature furnaces. A self-grown single crystal using solution processes is already introduced in perovskite photovoltaic technology and it can be the key for low-cost scintillators. A novel class of materials in scintillation includes lead halide perovskites. These materials were explored decades ago due to the large X-ray absorption cross section. However, lately lead halide perovskites have become a focus of interest due to recently reported very high photoluminescence quantum yield and light yield conversion at low temperatures. In principle, 150,000–300,000 photons/MeV light yields can be proportional to the small energy bandgap of these materials, which is below 2 eV. Finally, we discuss the extraction efficiency improvements through the fabrication of the nanostructure in scintillators, which can be implemented in perovskite materials. The recent technology involving quantum dots and nanocrystals may also improve light conversion in perovskite scintillators.

scholarly journals Comparison of Neutron Detection Performance of Four Thin-Film Semiconductor Neutron Detectors Based on Geant4

Sensors ◽  
2021 ◽  
Vol 21 (23) ◽  
pp. 7930
Author(s):  
Zhongming Zhang ◽  
Michael D. Aspinall
Keyword(s):  
Thin Film ◽  
High Temperature ◽  
High Energy Physics ◽  
Detection Efficiency ◽  
Collection Efficiency ◽  
Radiation Detectors ◽  
High Energy ◽  
Semiconductor Materials ◽  
Third Generation ◽  
Neutron Detectors

Third-generation semiconductor materials have a wide band gap, high thermal conductivity, high chemical stability and strong radiation resistance. These materials have broad application prospects in optoelectronics, high-temperature and high-power equipment and radiation detectors. In this work, thin-film solid state neutron detectors made of four third-generation semiconductor materials are studied. Geant4 10.7 was used to analyze and optimize detectors. The optimal thicknesses required to achieve the highest detection efficiency for the four materials are studied. The optimized materials include diamond, silicon carbide (SiC), gallium oxide (Ga2O3) and gallium nitride (GaN), and the converter layer materials are boron carbide (B4C) and lithium fluoride (LiF) with a natural enrichment of boron and lithium. With optimal thickness, the primary knock-on atom (PKA) energy spectrum and displacements per atom (DPA) are studied to provide an indication of the radiation hardness of the four materials. The gamma rejection capabilities and electron collection efficiency (ECE) of these materials have also been studied. This work will contribute to manufacturing radiation-resistant, high-temperature-resistant and fast response neutron detectors. It will facilitate reactor monitoring, high-energy physics experiments and nuclear fusion research.

Lead Tungstate For High Energy Calorimetry

1994 ◽  
Vol 348 ◽  
Author(s):  
I. Dafinei ◽  
E. Auffray ◽  
P. Lecoq ◽  
M. Schneegans
Keyword(s):  
Energy Resolution ◽  
Spectroscopic Data ◽  
High Energy Physics ◽  
Light Yield ◽  
High Energy ◽  
Lead Tungstate ◽  
Low Light ◽  
Physics Experiments ◽  
Energy Physics ◽  
Detector Volume

ABSTRACTThe very large volumes needed to build a crystal calorimeter for High Energy Physics experiments bring cost considerations at the front of the stage. A reasonable compromise between cost and performances must be reached. One possible solution is to look at very dense materials like PbWO4, which will reduce the detector volume, even if the relatively low light yield will impose some limitations to the energy resolution. A review of the different results obtained by the Crystal Clear collaboration will be given for this crystal, including spectroscopic data and radiation damage measurements.

Developments and Applications for All-Aluminum Alloy Vacuum Systems

MRS Bulletin ◽  
1990 ◽  
Vol 15 (7) ◽  
pp. 23-31 ◽  
Author(s):  
Hajime Ishimaru
Keyword(s):  
Aluminum Alloy ◽  
Aluminum Alloys ◽  
High Energy Physics ◽  
New Technology ◽  
Pure Aluminum ◽  
National Laboratory ◽  
High Heat ◽  
High Energy ◽  
Heat Fluxes ◽  
Surface Finishing

Aluminum and aluminum alloys have long been among the preferred materials for ultrahigh vacuum (UHV) systems operating in the 10−10–10−11 torr (10−8–10−11 Pa) range. Pure aluminum and aluminum alloys have an extremely low outgassing rate, are completely nonmagnetic, lack crystal structure transitions at low temperatures, are not sources of heavy metals contamination in semiconductor processing applications, have low residual radioactivity in radiation environments, and are lightweight. Because of aluminum's high thermal conductivity and low thermal emissivity, aluminum components can tolerate high heat fluxes in spite of the relatively low melting point of aluminum.Recently developed aluminum alloys and new surface finishing techniques allow the attainment of extremely high vacuums (XHV) in the 10−12–10−13 torr (10−10–10−11 Pa) range. XHV technology requires the use of special aluminum alloy flange/gasket/bolt, nut and washer combinations, aluminum alloy-ceramic seals, windows, bellows, right-angle and gate valves, turbomolecular pumps, sputter ion pumps and titanium sublimination pumps, Bayard-Alpert ion gauges, quadrupole mass filters, and related aluminum alloy vacuum components. New surface treatment methods and new techniques in welding and extremely sensitive helium leak testing are required. In short, a whole new technology has been developed to take advantage of the opportunities presented by these new vacuum materials. This article describes some of these newly developed fabrication technologies and vacuum materials.The TRISTAN electron-positron collider constructed at the National Laboratory for High Energy Physics in Japan is the first all-aluminum alloy accelerator, and the first to use UHV technology.

scholarly journals Prospects for High Energy Resolution Gamma Ray Spectroscopy with Europium-Doped Strontium Iodide

2009 ◽  
Vol 1164 ◽  
Author(s):  
Nerine Cherepy ◽  
S A. Payne ◽  
Rastgo Hawrami ◽  
A Burger ◽  
Lynn Boatner ◽  
...  
Keyword(s):  
Energy Resolution ◽  
Gamma Ray ◽  
Light Yield ◽  
Crystal Form ◽  
High Energy ◽  
High Energy Resolution ◽  
Light Collection ◽  
Chemical Homogeneity ◽  
Crystal Structural ◽  
Crystal Volume

AbstractEuropium-doped strontium iodide scintillators offer a light yield exceeding 100,000 photons/MeV and excellent light yield proportionality, while at the same time, SrI2 is readily grown in single crystal form. Thus far, our collaboration has demonstrated an energy resolution with strontium iodide of 2.6% at 662 keV and 7.6% at 60 keV, and we have grown single crystals surpassing 30 cm3 in size (with lower resolution). Our analysis indicates that SrI2(Eu) has the potential to offer 2% energy resolution at 662 keV with optimized material, optics, and read-out. In particular, improvements in feedstock purity may result in crystal structural and chemical homogeneity, leading to improved light yield uniformity throughout the crystal volume, and consequently, better energy resolution. Uniform, efficient light collection and detection, is also required to achieve the best energy resolution with a SrI2(Eu) scintillator device.

Intrinsic Light Yield and Loss Parameter of Y2SiO5:Ce Single Crystal Scintillator

2017 ◽  
Vol 866 ◽  
pp. 329-332
Author(s):  
Akapong Phunpueok ◽  
Voranuch Thongpool ◽  
Weerapong Chewpraditkul
Keyword(s):  
Single Crystal ◽  
Energy Resolution ◽  
High Energy Physics ◽  
Gamma Ray ◽  
Light Yield ◽  
Czochralski Method ◽  
High Energy ◽  
Thick Sample ◽  
Loss Parameter ◽  
Thick Crystal

Nowadays, single crystal scintillators play an key role in the scientific researches, high-energy physics and modern medical imaging. In this research, we studied the scintillation response of polished yttrium oxyorthosilicate with Ce-doped (Y2SiO5:Ce, YSO(Ce)) crystals grown by the Czochralski method. The nominal Ce3+ ion is about 0.5% for tested crystals. Energy resolution and photon yield of the scintillator are read out by the photomultiplier tube (XP5200B PMT) under excitation with gamma-rays. The polished YSO:Ce samples (5x5x1 mm3 and 5x5x3 mm3) was tested at room temperature. The 1 mm thick sample shows the better energy resolution than the 3 mm thick crystal. The light yield dependences on the height of crystal were evaluated under excitation with 662 keV gamma ray energy and the intrinsic light yield and loss parameter were also determined.

Lead tungstate scintillation crystals with improved light yield for experimental high-energy physics

2006 ◽  
Vol 49 (2) ◽  
pp. 199-202
Author(s):  
A. E. Borisevich ◽  
V. I. Dormenev ◽  
M. V. Korzhik ◽  
O. V. Misevich ◽  
A. A. Fedorov
Keyword(s):  
High Energy Physics ◽  
Light Yield ◽  
High Energy ◽  
Lead Tungstate ◽  
Scintillation Crystals ◽  
Energy Physics

High energy resolution spectrometer for the dedicated STEM

1984 ◽  
Vol 42 ◽  
pp. 558-559 ◽  
Author(s):  
P.E. Batson
Keyword(s):  
Collection Efficiency ◽  
Core Loss ◽  
Beam Current ◽  
High Energy ◽  
High Energy Resolution ◽  
Acquisition Time ◽  
Good Definition ◽  
Loss Analysis ◽  
Definition Of ◽  
Acceleration Voltage

Use of the STEM to obtain precise electronic information has been hampered by the lack of energy loss analysis capable of a resolution and accuracy comparable to the 0.3eV energy width of the Field Emission Source. Recent work by Park, et. al. and earlier by Crewe, et. al. have promised magnetic sector devices that are capable of about 0.75eV resolution at collection angles (about 15mR) which are great enough to allow efficient use of the STEM probe current. These devices are also capable of 0.3eV resolution at smaller collection angles (4-5mR). The problem that arises, however, lies in the fact that, even with the collection efficiency approaching 1.0, several minutes of collection time are necessary for a good definition of a typical core loss or electronic transition. This is a result of the relatively small total beam current (1-10nA) that is available in the dedicated STEM. During this acquisition time, the STEM acceleration voltage may fluctuate by as much as 0.5-1.0V.

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