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LHCb ECal UpGrade (ver. PWO)

LHCb ECal UpGrade (ver. PWO). Excellent resolutions (having it even in central region only will be useful for many physical studies) Very dense (small X 0 , R M ) -- helps in pile-up environments (should be proof how much)

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LHCb ECal UpGrade (ver. PWO)

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  1. LHCb ECal UpGrade (ver. PWO) Excellent resolutions (having it even in central region only will be useful for many physical studies) Very dense (small X0, RM) -- helps in pile-up environments (should be proof how much) -- more complicated software treatment at the borders Shashlyk-PWO (is it problem?) Prove to be rad. hard. (to some extends) Extensively developed and studied in the past decade (still continued) From Korzhik’s talk 26.03.09 LHCbCalorimeters UpgradeMeeting, A.Ostankov, IHEP, Protvino

  2. PWO radiation hardness Has been tested up to few Mrad( mainly with γ, n – sources, e - beams) It is proved: 1). Radiation changes optical properties (transparency @ blue region) but not scint. mechanism => could be monitored 2). Changes are related to electrons excitations rather than atomic structure destroying => annealing => recovery => complicated picture of the damages in time (varied crystal to crystal) => must be monitored & able to be monitored 3). Saturation effect at given dose rate <= as consequence of (2) 4). To some extend all of that have been supported by irradiations by hadrons CMS approved these crystals to use To my knowledge the most systematic measurements supported conclusions mentioned above using irradiation by hadrons (40 GeVpions) have been performed at Protvino for BTeV, NIM A530 (2004) 286. It has been done for dose rate up to ~20 rad/h (i.e. ~0.1 Mrad/SMY) ¡ So far so good ! 26.03.09 LHCbCalorimeters UpgradeMeeting, A.Ostankov, IHEP, Protvino

  3. 2. DAMAGE BY CHARGED HADRONS. From Korzhik’s talk FRENKEL TYPE DEFECTS- KNOCKING OUT OF OXYGEN IONS IN INTERSITE POSITIONS COURTESY OF Dr.F.Nessi-Tedaldi, CERN Optical transmission spectra of PWO crystal change after irradiation with protons . (M. Huhtinen, P. Lecomte, D. Luckey, F. Nessi-Tedaldi, F. Pauss, NIM A 545(2005)63-87) 19.03.09 LHCbUpgradeMeeting

  4. PWO radiation hardness continued with 20 GeV protons @PS to go deeper to the η with hadrons Optical properties (transparency) have been studied only. Above 1013 20 GeV p/cm2 total flux (1 Mrad, @ 1012 p/cm2 *h rate, min. allowed) -- no annealing, no recovery (@1 year!), no saturation, effect of optical damages is accumulated -- cut-off of transmission spectrum is shifted to the right No conclusion about scint. mechanism, monitoring is still possible but basically useless at such conditions Worse consequence: for CMS: save operation @ nominal L up to η~2.1 => good fraction of End-Caps will not work. Room for optimism – hadron spectrum contains many species, not protons only => studies should be continued in particular by looking for more R.H. crystals (green light PWOM mentioned above) for LHCb Ecal: according TDR – in the most central region we have 1012 hadrons (E>20 MeV)/cm2 * year) at nominal L. => We are at the border of safety for High L. Bad news – R&D is needed to use any PWO in LHCb for high L Really bad news – anyway it’s needed even in case of Shashlyk use for high L. 26.03.09 LHCbCalorimeters UpgradeMeeting, A.Ostankov, IHEP, Protvino

  5. LHCb ECal UpGrade (ver. Shashlyk) 26.03.09 LHCbCalorimeters UpgradeMeeting, A.Ostankov, IHEP, Protvino

  6. 2. DAMAGE WITH NEUTRONS. From Korzhik’s talk Before irradiation FRENKEL TYPE DEFECTS- KNOCKING OUT OF OXYGEN IONS IN INTERSITE POSITIONS after irradiation by fast neutrons with 1.6*1020 n/cm2 integral fluence Optical transmission spectra of 0,2 mmPWO crystal after 1.6*1020 n/cm2 (M.Korzhik, Physics of scintillation in oxide crystals, Minsk, 2003, 263 p. (In Russian)) No damage is expected with SLHC expected fluence 5·1013n/cm2 at the scintillation spectral maximum (420 nm), Δk is less than 0.01m-1 19.03.09 LHCbUpgradeMeeting

  7. The ECAL Irradiation In vicinity of IP VELO IP ~200 mrad 26.03.2009 Alexander OSTANKOV (IHEP, Protvino)

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