Characterization of lead tungstate crystals optical properties for CERN CMS ECAL
Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesisAlternative title
Karakterisering av bly-wolfram-oxid kristallers optiska egenskaper till CERNs CMS ECAL (Swedish)
The Large Hadron Collider (LHC) at CERN have a capacity to produce protonproton collisions with an energy of 14 TeV. Four particle detectors are included in the LHC with the purpose to detect all the particles that are created in the collisions. In one of these detectors are scintillating lead tungstate crystals used, to detect the energy of photons and electrons created in the collisions. The energy is detected by measuring of the emitted light from the scintillating crystals. As much knowledge as possible about the optical properties of the crystals are desired to be able to analyze the acquired data from the crystals.
This thesis work presents some techniques used for the characterization of the optical properties for the crystals. It also presents measurements done on the decay time of lead tungstate crystals and on the temperature influence to the light yield from the crystals. These measurement results are in addition used in an attempt to estimate how big influence the Cherenkov radiation has to the total amount of emitted light from the scintillating crystals.
The influence from the temperature to the light yield is around −2.02 %/◦C for BTCP and around −1.75 %/◦C for SIC1. No conclusions could been drawn concerning the influence from the Cherenkov radiation to the total amount of emitted light from the temperature measurements.The decay time measurements showed an influence from the Cherenkov radiation to the total amount of emitted light of; 8 % for crystal 1003, 47 % for crystal 1002 and 19 % for crystal 1001.
1BTCP (Bogoroditsk Technical Chemical Plant) and SIC (Shanghai Institute of Ceramics) are the two different crystal production facilities used for the production of the crystals.
Place, publisher, year, edition, pages
2008. , 60 p.
CERN, CMS, lead tungstate crystals, optical properties
IdentifiersURN: urn:nbn:se:liu:diva-16595ISRN: LITH-IFM-A-EX--08/2026--SEOAI: oai:DiVA.org:liu-16595DiVA: diva2:210060
Auffray Hillemans, Etiennette
Arwin, Hans, Professor