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Mapping residual stresses in PbWO$_{4}$ crystals using photo-elastic analysis

Large scintillating crystals are affected by internal stresses induced by the crystal growth temperature gradient remanence. Cutting boules (ingots) into finished crystal shapes allows for a partial tension relaxation but residual stresses remain the main cause of breaking. Quality control of residu...

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Detalles Bibliográficos
Autores principales: Lebeau, Michel, Gobbi, L, Majni, G, Paone, N, Pietroni, P, Rinaldi, D
Lenguaje:eng
Publicado: 2005
Materias:
Acceso en línea:https://dx.doi.org/10.1016/j.nima.2004.07.256
http://cds.cern.ch/record/912958
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author Lebeau, Michel
Gobbi, L
Majni, G
Paone, N
Pietroni, P
Rinaldi, D
author_facet Lebeau, Michel
Gobbi, L
Majni, G
Paone, N
Pietroni, P
Rinaldi, D
author_sort Lebeau, Michel
collection CERN
description Large scintillating crystals are affected by internal stresses induced by the crystal growth temperature gradient remanence. Cutting boules (ingots) into finished crystal shapes allows for a partial tension relaxation but residual stresses remain the main cause of breaking. Quality control of residual stresses is essential in the application of Scintillating Crystals to high-energy physics calorimeters (e.g. CMS ECAL at CERN LHC). In this context the industrial process optimisation towards stress reduction is mandatory. We propose a fast technique for testing samples during the production process in order to evaluate the residual stress distribution after the first phases of mechanical processing. We mapped the stress distribution in PbWO/sub 4/slabs cut from the same production boule. The analysis technique is based on the stress intensity determination using the photo-elastic properties of the samples. The stress distribution is mapped in each sample. The analysis shows that there are regions of high residual tension close to the seed position and at the boule periphery. These results should allow for adapting the industrial process to producing crystals with lower residual stresses.
id cern-912958
institution Organización Europea para la Investigación Nuclear
language eng
publishDate 2005
record_format invenio
spelling cern-9129582019-09-30T06:29:59Zdoi:10.1016/j.nima.2004.07.256http://cds.cern.ch/record/912958engLebeau, MichelGobbi, LMajni, GPaone, NPietroni, PRinaldi, DMapping residual stresses in PbWO$_{4}$ crystals using photo-elastic analysisDetectors and Experimental TechniquesLarge scintillating crystals are affected by internal stresses induced by the crystal growth temperature gradient remanence. Cutting boules (ingots) into finished crystal shapes allows for a partial tension relaxation but residual stresses remain the main cause of breaking. Quality control of residual stresses is essential in the application of Scintillating Crystals to high-energy physics calorimeters (e.g. CMS ECAL at CERN LHC). In this context the industrial process optimisation towards stress reduction is mandatory. We propose a fast technique for testing samples during the production process in order to evaluate the residual stress distribution after the first phases of mechanical processing. We mapped the stress distribution in PbWO/sub 4/slabs cut from the same production boule. The analysis technique is based on the stress intensity determination using the photo-elastic properties of the samples. The stress distribution is mapped in each sample. The analysis shows that there are regions of high residual tension close to the seed position and at the boule periphery. These results should allow for adapting the industrial process to producing crystals with lower residual stresses.oai:cds.cern.ch:9129582005
spellingShingle Detectors and Experimental Techniques
Lebeau, Michel
Gobbi, L
Majni, G
Paone, N
Pietroni, P
Rinaldi, D
Mapping residual stresses in PbWO$_{4}$ crystals using photo-elastic analysis
title Mapping residual stresses in PbWO$_{4}$ crystals using photo-elastic analysis
title_full Mapping residual stresses in PbWO$_{4}$ crystals using photo-elastic analysis
title_fullStr Mapping residual stresses in PbWO$_{4}$ crystals using photo-elastic analysis
title_full_unstemmed Mapping residual stresses in PbWO$_{4}$ crystals using photo-elastic analysis
title_short Mapping residual stresses in PbWO$_{4}$ crystals using photo-elastic analysis
title_sort mapping residual stresses in pbwo$_{4}$ crystals using photo-elastic analysis
topic Detectors and Experimental Techniques
url https://dx.doi.org/10.1016/j.nima.2004.07.256
http://cds.cern.ch/record/912958
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