scholarly journals Precision Machining And Polishing Of Scintillating Crystals For Large Calorimeters And Hodoscopes

1994 ◽  
Vol 348 ◽  
Author(s):  
Craig R. Wuest ◽  
Baruch A. Fuchs ◽  
Fred R. Holdener ◽  
Joaquim L. Heck
Keyword(s):  
Surface Damage ◽  
Cesium Iodide ◽  
Barium Fluoride ◽  
Electromagnetic Calorimeter ◽  
Precision Machining ◽  
Rutherford Back Scattering ◽  
Cerium Fluoride ◽  
Detailed Surface ◽  
Production Techniques ◽  
Babar Detector

ABSTRACTNew machining and polishing techniques have been developed for large scintillating crystal arrays such as the Barium Fluoride Electromagnetic Calorimeter for the GEM Detector at SSCL, the Crystal Clear Collaboration's cerium fluoride or lead tungstenate calorimeter at the proposed LHC at CERN, the PHENIX Detector at RHIC (barium fluoride), and the cesium iodide Calorimeter for the BaBar Detector at PEP-I B Factory at SLAC. The machining and polishing methods to be presented in this paper provide crystalline surfaces without sub-surface damage or deformation as verified by Rutherford Back-scattering (RBS) analysis. Surface roughness of about 10-20 angstroms and sub-micron mechanical tolerances have been demonstrated on large barium fluoride crystal samples. Mass production techniques have also been developed for machining the proper angled surfaces and polishing up to five 50 cm long crystals at one time. These techniques utilize kinematic mount technology developed at LLNL to allow precision machining and polishing of complex surfaces. We will present this technology along with detailed surface studies of barium fluoride and cerium fluoride crystals polished with this technique.

Tests of cesium iodide crystals for an electromagnetic calorimeter

1986 ◽  
Vol 249 (2-3) ◽  
pp. 201-227 ◽  
Author(s):  
E. Blucher ◽  
B. Gittelman ◽  
B.K. Heltsley ◽  
J. Kandaswamy ◽  
R. Kowalewski ◽  
...  
Keyword(s):  
Cesium Iodide ◽  
Electromagnetic Calorimeter

Barium Fluoride Crystals for Future Hadron Colliders

1994 ◽  
Vol 348 ◽  
Author(s):  
Ren-yuan Zhu ◽  
Da-an Ma ◽  
Harvey Newman
Keyword(s):  
Radiation Resistance ◽  
Production Quality ◽  
Barium Fluoride ◽  
Electromagnetic Calorimeter ◽  
Hadron Colliders ◽  
Excellent Candidate ◽  
Current Production ◽  
Fluoride Crystals ◽  
Optical Bleaching

ABSTRACTThis report summarizes the radiation resistance of the current production BaF2 crystals. An approach to implement optical bleaching in situ is also presented. By using optical bleaching current production quality BaF2 crystals could serve as an excellent candidate to construct a precision electromagnetic calorimeter at future hadron colliders.

scholarly journals Development, construction and tests of the Mu2e electromagnetic calorimeter mechanical structures

2022 ◽  
Vol 17 (01) ◽  
pp. C01007
Author(s):  
N. Atanov ◽  
V. Baranov ◽  
L. Borrel ◽  
C. Bloise ◽  
J. Budagov ◽  
...  
Keyword(s):  
Cooling System ◽  
Plastic Material ◽  
Thermal Contact ◽  
Electronics Cooling ◽  
Structure Design ◽  
Cesium Iodide ◽  
Electromagnetic Calorimeter ◽  
Track Reconstruction ◽  
Operational Conditions ◽  
Front End

Abstract The “muon-to-electron conversion” (Mu2e) experiment at Fermilab will search for the charged lepton flavour violating neutrino-less coherent conversion of a muon into an electron in the field of an aluminum nucleus. The observation of this process would be the unambiguous evidence of the existence of physics beyond the standard model. Mu2e detectors comprise a straw-tracker, an electromagnetic calorimeter and an external veto for cosmic rays. In particular, the calorimeter provides excellent electron identification, a fast calorimetric online trigger, and complementary information to aid pattern recognition and track reconstruction. The detector has been designed as a state-of-the-art crystal calorimeter and employs 1348 pure Cesium Iodide (CsI) crystals readout by UV-extended silicon photosensors and fast front-end and digitization electronics. A design consisting of two identical annular matrices (named “disks”) positioned at the relative distance of 70 cm downstream the aluminum target along the muon beamline satisfies the Mu2e physics requirements. The hostile Mu2e operational conditions, in terms of radiation levels (total expected ionizing dose of 12 krad and a neutron fluence of 5 × 1010 n/cm2 @ 1 MeVeq (Si)/y), magnetic field intensity (1 T) and vacuum level (10−4 Torr) have posed tight constraints on scintillating materials, sensors, electronics and on the design of the detector mechanical structures and material choice. The support structure of each 674 crystal matrix is composed of an aluminum hollow ring and parts made of open-cell vacuum-compatible carbon fiber. The photosensors and front-end electronics for the readout of each crystal are inserted in a machined copper holder and make a unique mechanical unit. The resulting 674 mechanical units are supported by a machined plate of vacuum-compatible plastic material. The plate also integrates the cooling system made of a network of copper lines flowing a low temperature radiation-hard fluid and placed in thermal contact with the copper holders to constitute a low resistance thermal bridge. The data acquisition electronics are hosted in aluminum custom crates positioned on the external lateral surface of the disks. The crates also integrate the electronics cooling system as lines running in parallel to the front-end system. In this paper we report on the calorimeter mechanical structure design, the mechanical and thermal simulations that have determined the design technological choices, and the status of component production, quality assurance tests and plans for assembly at Fermilab.

Research on the Precision Machining on SiC

2014 ◽  
Vol 900 ◽  
pp. 601-604
Author(s):  
Qiang Xiao ◽  
Xue Li He
Keyword(s):  
Single Crystal ◽  
Material Removal ◽  
Surface Damage ◽  
Precision Machining ◽  
Depth Of Cut ◽  
Brittle To Ductile Transition ◽  
Elid Grinding ◽  
Ductile Mode ◽  
Grinding Mechanism ◽  
Critical Depth Of Cut

SiC material removal mechanism and ELID grinding mechanism is analyzed, the character and condition of brittle to ductile transition of SiC single crystal, the critical depth of cut, and surface formation mechanism of ductile mode grinding of SiC single crystal are studied, the experiment results show that ELID grinding can realize ductile grinding ,this will lower the surface damage and improve the machining efficiency.

Investigation of the Polishing Mechanism of Magnetorheological Elastic Polishing Composites

2021 ◽  
Author(s):  
Zhiqiang Xu ◽  
Jun Wang ◽  
Qiuliang Wang ◽  
Heng Wu ◽  
Gaofeng Zhang ◽  
...  
Keyword(s):  
Complex Surface ◽  
Surface Damage ◽  
Contact Theory ◽  
Precision Machining ◽  
Tool Influence Function ◽  
Ultra Precision ◽  
Computer Controlled ◽  
Preliminary Study ◽  
Polishing Tool ◽  
Quality Surface

Abstract Computer-controlled ultra-precision polishing technology is widely used for high-quality surface processing. However, its polishing tool has some shortcomings, such as limited adaptability to the complex surface and easy to cause surface damage. Therefore, a new smart material-based abrasive tool named magnetorheological elastic polishing composites (MREPCs) and its flexible polishing method are proposed. This study first prepared MREPCs and developed a polishing tool for MREPCs. Then, the material properties of MREPCs were obtained by theoretical and experimental analysis, and the tool influence function (TIF) of the hemispherical MRPECs was established according to the Hertz contact theory, the variable rheological theory and the Preston equation. Finally, the TIF and the polishing performance of MREPCs were verified by polishing experiments. The results show that the theoretical and the experimentally measured TIF models have a high coincidence, and the developed MREPCs can remove surface material with high precision. The above preliminary study indicates that MREPCs are promising for ultra-precision machining of small-sized parts with complex profiles.

Investigation on the Surface Finish, MRR and the Surface Damage during the EDM of Tungsten Carbide

2011 ◽  
Vol 264-265 ◽  
pp. 1073-1078 ◽  
Author(s):  
Ahsan Ali Khan ◽  
Suleiman Abdulkareem ◽  
Nadiatul Amirah Ahmad Abdul Ghani ◽  
Dayanna Sarrah Mohammad Ariffin
Keyword(s):  
Surface Finish ◽  
Removal Rate ◽  
Surface Damage ◽  
Precision Machining ◽  
Dielectric Fluid ◽  
Electric Discharges ◽  
Hard Materials ◽  
Nontraditional Method ◽  
Finish Material ◽  
Pulse On Time

EDM is a nontraditional method of removing material by a series of rapidly recurring electric discharges between an electrode (the cutting tool) and the workpiece, in a medium of a dielectric fluid. EDM is a precision machining technique and is used in making dies and molds of extremely hard materials that cannot be machined by conventional techniques. The present work was conducted in order to investigate the surface finish, material removal rate and the surface damage during EDM. Copper and carbide were taken as the electrode and the work materials for the present study. The influence of current and pulse-on time on the responses were studied. Design of Experiment (DOE) was used to conduct the investigation. It was found that MRR and surface roughness increases with both current and pulse on time. Tool wear, work surface damage and materials migration between the electrode and the workpiece was found to be increased with current.

Fillers and Dissolvent in Porous Self-Generating Fine Super-Hard Abrasive Tool

2010 ◽  
Vol 135 ◽  
pp. 398-403 ◽  
Author(s):  
Hong Wei Fan ◽  
Bing Hai Lv ◽  
Ju Long Yuan ◽  
Q.F. Deng ◽  
W.F. Yao
Keyword(s):  
Metal Oxide ◽  
Surface Damage ◽  
Ceramic Materials ◽  
Precision Machining ◽  
Machining Efficiency ◽  
Metallic Oxide ◽  
Advanced Ceramics ◽  
Key Technology ◽  
Fecl3 Solution ◽  
Metal Metal

In order to obtain low surface damage and high machining efficiency for advanced ceramics, overcome clogging and dressing difficulties of traditional metal bonded super-hard abrasive, a novel fine super-hard abrasive with porous self-generating ability is proposed in this paper. And the matching of filler and dissolvent in abrasive are studied. Soluble filler is a key technology of porous self-generating fine super-hard abrasive. In this paper, metal, metal oxide and non-metallic oxide are respectively used as soluble fillers. Results of the experimental shows: In metal bonded super-hard abrasive, metal, metal oxide and non-metallic oxide as soluble filler are feasible, correspondingly, FeCl3 solution, aqueous solution and weak alkaline solution are used as dressing dissolvent, respectively. It can be met the requirement of high precision machining for advanced ceramic materials, hard and brittle machining materials.

Surface Structure in Microtomed Sections Caused by Glass and Diamond Knives

1971 ◽  
Vol 29 ◽  
pp. 456-457
Author(s):  
J. Temple Black ◽  
William G. Boldosser
Keyword(s):  
Plastic Deformation ◽  
Epoxy Resin ◽  
Carbon Coating ◽  
Surface Damage ◽  
Body Angle ◽  
Normal Manner ◽  
Bottom Side ◽  
Cutting Direction ◽  
Made In ◽  
Diamond Knife

Ultramicrotomy produces plastic deformation in the surfaces of microtomed TEM specimens which can not generally be observed unless special preparations are made. In this study, a typical biological composite of tissue (infundibular thoracic attachment) infiltrated in the normal manner with an embedding epoxy resin (Epon 812 in a 60/40 mixture) was microtomed with glass and diamond knives, both with 45 degree body angle. Sectioning was done in Portor Blum Mt-2 and Mt-1 microtomes. Sections were collected on formvar coated grids so that both the top side and the bottom side of the sections could be examined. Sections were then placed in a vacuum evaporator and self-shadowed with carbon. Some were chromium shadowed at a 30 degree angle. The sections were then examined in a Phillips 300 TEM at 60kv.Carbon coating (C) or carbon coating with chrom shadowing (C-Ch) makes in effect, single stage replicas of the surfaces of the sections and thus allows the damage in the surfaces to be observable in the TEM. Figure 1 (see key to figures) shows the bottom side of a diamond knife section, carbon self-shadowed and chrom shadowed perpendicular to the cutting direction. Very fine knife marks and surface damage can be observed.

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