Energy Resolution and Timing Performance Studies of a W-CeF 3 - PowerPoint PPT Presentation

Energy Resolution and Timing Performance Studies of a W-CeF 3 Sampling Calorimeter prototype with a Wavelength-Shifting Fiber Readout Francesca Nessi-Tedaldi ETH Zürich on behalf of the W-CeF 3 R&D group N. Akchurin j , R. Becker a , B. Betev a , L. Bianchini a , L. Brianza b , V. Candelise e,h , F. Cavallari c , N. Chiodini b,i , I. Dafinei c , G. Della Ricca e,h , D. del Re c,g , M. Diemoz c , G. D’Imperio c,g , G. Dissertori a , L. Djambazov a , M. Donegà a , M. Droege a , M. Fasoli b,i , J. Faulkner j , S. Gelli c,g , A. Ghezzi b , P . Govoni b , C. Haller a , U. Horisberger a , Th. Klijnsma a , W. Lustermann a , A. Marini a , A. Martelli b,f , D. Meister a , F. Micheli a , P . Meridiani c , V. Monti d , F. Nessi-Tedaldi a , M. Nuccetelli c , G. Organtini c,g , F. Pandolfi a , R. Paramatti c,g , N. Pastrone d , F. Pellegrino c , M. Peruzzi a , S. Pigazzini b,f , M. Quittnat a , S. Rahatlou c,g , C. Rovelli c , F. Santanastasio c,g , M. Schönenberger a , L. Soffi c,g , T. Tabarelli de Fatis b,f , P . Trapani d , F. Vazzoler e,h , A. Vedda b,i a) ETH Zürich INFN: b) Sez. Milano-Bicocca, c) Sez. Roma, d) Sez. Torino, e) Sez. Trieste f) Università di Milano-Bicocca g) Università di Roma “La Sapienza” h) Università di Trieste i) Dip. Scienza dei Materiali, Università di Milano-Bicocca Int. Conf. on Technology and Instrumentation in Particle Physics 2017 Beijing, May 24 th , 2017

Original motivation: HL-LHC radiation environment in CMS ✦ HL-LHC (~2025): a harsh environment for electromagnetic calorimetry (ECAL) • 𝜹 dose rate up to 50 Gy/h, dose up to ~1 MGy (at η = 3) • Hadron fluences up to ~4x10 14 cm -2 (average energy a few GeV) • Neutron fluences up to ~5x10 15 cm -2 (average energy 1 MeV) • Radiation-induced transparency losses in PbWO 4 resulting in an energy resolution degradation • Upgrade for HL-LHC: complete replacement of ECAL endcaps + partial ECAL barrel upgrade Hadron fluence [cm -2 ] , 14 TeV pp, 100 fb -1 0 S/S MC simulation 1 Fraction of ECAL response -1 10 ECAL Barrel ECAL PbWO 4 endcap -1 -2 -1 10 fb , 5E+33 cm s -2 10 -1 -2 -1 100 fb , 1E+34 cm s -1 -2 -1 500 fb , 2E+34 cm s -1 -2 -1 1000 fb , 5E+34 cm s -1 -2 -1 2000 fb , 5E+34 cm s -1 -2 -1 3000 fb , 5E+34 cm s -3 10 1.5 2 2.5 3 η CMS Coll., CMS DP-2013/028 CMS Coll., CERN-LHCC-2015-010 Francesca Nessi-Tedaldi ETH Zürich 2

Strategy: a simple geometry F. N.-T. et al., CALOR 2014, JoP Conf. Ser. 587 (2015) 012039 ✦ Use an inorganic scintillator that is adequately radiation-tolerant chamfer ✦ Build a sampling calorimeter ✦ Extract the light by WLS fibers running along depolished chamfers • minimising the machining and construction complexity, thus saving on costs Photodetector • minimising the light path, thus reduces crystal radiation damage effects • optimising the Molière radius, thus cell size, for pile-up mitigation Fibre ✦ Two setups: • Single-channel prototype → energy resolution, uniformity • 5 x 3 channel matrix → angular dependence Francesca Nessi-Tedaldi ETH Zürich 3

CeF 3 crystal scintillator Tokuyama CeF 3 transmission and 60Co LY spectrum (inset) after γ -irradiation 100 Density [g/cm 3 ] 6.16 before and after overlaid! 90 Refractive index 1.62 after 8kGy@42 Gy/h 80 UV 1000 Peak luminescence [nm] 340 Before Transmittance [%] 70 1.2hours 2.7hours fast 60 5.3hours Decay time [ns] ~30 6.7hours 100 8.0hours 50 5days Counts dLY/dT [%/ o C] 0.14 Recovered 40 0.4 hours 10 ✦ Ionising radiation : 30 20 1 • Can be made to recover 10 0 50 100 150 200 Pulse Height [ch] 0 • Studied in the ’90 for CMS 1) 250 350 450 550 650 750 850 950 1050 Wavelength [nm] � • Studies performed on new crystals Induced absorption coefficient recovery after p-irradiation ] -1 from Tokuyama, Japan 2) (340 nm) [m 4 ✦ Hadron fluences: IND µ CeF no build-up • Can be made to recover 3 2 p - irradiated • Proven on 20 y old crystal 3) 0 0 100 200 300 400 1) E. Auffray (CERN) et al., NIM A 383 (1996) 367-390 t [days] 2) F. N.-T. et al. , SCINT 2015, Berkeley (USA) 3) G. Dissertori et al., NIM A 622 (2010) 41-48 Francesca Nessi-Tedaldi ETH Zürich 4

Single-channel prototype ★ Dimensions chosen within CMS ECAL PbWO 4 crystals envelope • (10 mm CeF 3 + 3 mm W) x 15 layers = 19.5 cm = 25 X 0 • depolished chamfers, 3 mm wide, accomodate 1 mm ∅ fibers • Effective R M = 23 mm, transverse dimensions 24 mm x 24 mm, SF = 38% • For the tests in beam, surrounded by BGO crystals for shower containment • Kuraray 3HF-SC (1500) plastic fibers as WLS • Each WLS fiber read out independently by a PMT • Energy resolution and uniformity studies Francesca Nessi-Tedaldi ETH Zürich 5

Intrinsic energy resolution CERN SPS, October 2014 Trigger Scintillators smallest one 1 x 1 cm 2 H4 electron beam 20 - 150 GeV ★ Central events selection: • 6 x 6 mm 2 of front face Wire Chambers and fiber Hodoscopes • Energy resolution measured 0.5 mm impact point accuracy ★ Single channel energy resolution dominated by lateral containment • Good agreement between data and Monte Carlo ★ The Monte Carlo extrapolation to a 5 x 5 channel matrix shows that an energy resolution stochastic term < 10% is achievable R. Becker et al., NIM A 804 (2015) 79 - 83 Francesca Nessi-Tedaldi ETH Zürich 6

W/CeF 3 channel Response Uniformity ✦ Response vs impact point can be studied through precise electron tracking. Although Light Collection effects are not corrected for, we observe: • Uniform response across central part of the channel • Lateral non-uniformities dominated by shower non-containment ✦ Data/simulation in good agreement (within 5%) ✦ Agreement on non-central region could be improved by including the light collection in the simulation R. Becker et al., NIM A 804 (2015) 79 - 83 Francesca Nessi-Tedaldi ETH Zürich 7

WLS: Ce-doped quartz fibres ✦ Ce-doped photoluminescent quartz (Ce:SiO 2 ) is a good WLS candidate with CeF 3 : • Ce:SiO 2 core (where light is produced) + cladding for light transport ✦ Ce:SiO 2 fibres developed for application to dosimetry 1) : • Radiation hardness anticipated up to fluences >10 15 cm -2 • Absorption spectrum matches CeF 3 emission 1.2 1.2 • Suitable as a WLS with CeF 3 λ max =464 nm λ max =329 nm λ em =465 nm Normalized PL (photons/nm) 1.0 1.0 • Fast time response (30 ns), green emission λ exc =300 nm 0.8 0.8 Normalized PLE • Development of rad-hard Ce:SiO 2 in progress 0.6 0.6 CeF 3 emission 0.4 0.4 peak 0.2 0.2 1) A. Vedda, N. Chiodini, M. Fasoli et al., Appl. Phys. Lett., Vol. 85 0.0 0.0 (2004) 6356 and priv. comm. (U. Milano Bicocca) 300 400 500 600 700 Wavelength (nm) Francesca Nessi-Tedaldi ETH Zürich 8 !

Tests with Ce:SiO 2 fibres Polymicro Kuraray ✦ CERN SPS H4 beam, June 2015 ✦ A bundle of SiO 2 :Ce fibres in each of 3 corners: o l y m 5 • 1 bundle from U. Milano-Bicocca 1) 7 i 1 c µ r m o F i b 3000 μ m e r s ( 3 • 2 bundles from Polymicro/Texas Tech 2) 3 0 - 0 olymicro Fibers (3-2-1 configuration) 2 5 7 0 1 µ m - 3 µ 0 0 1 0 m µ m Fibers (3-2-1 configuration) c Polymicro o F n Bicocca i fi b g e u r ✦ One Kuraray 3HF plastic fibre as reference r s a ( t 3 i o - 2 n - ) 1 c o 571 μ m n fi g u ✦ WLS efficiency is lower wrt Kuraray fibres: r a t i o n ) • bundle of Ce-doped quartz fibres: factor Fibres exposed to 365 nm light over ~ 15 cm ~10 less light than a plastic fibre • smaller diameter fibres: bundle of 6 SiO 2 :Ce fibres in each corner Bicocca Polymicro 1 Polymicro 2 1) A. Vedda, N. Chiodini, M. Fasoli et al., Appl. Phys. Lett., Vol. 85 (2004) 6356 and priv. comm. 2) Jordan Damgov, N. Akchurin et al., SCINT2015, Berkeley (USA) Francesca Nessi-Tedaldi ETH Zürich 9

Energy resolution with Ce:SiO 2 WLS fibres ✦ Central events selection: 3 x 3 mm 2 of front face ✦ Slightly different energy resolution for the different bundles of Ce:SiO 2 fibres ✦ Worse resolution compared to plastic fibres, consistent with ratio of photoluminescent light yields 100 GeV Electron Beam 3 10 × 100 GeV Electron Beam Events / 5.5 Events / 5.5 450 µ = 630 µ = 183 2.5 400 = 39 σ = 6 σ / = 6.1 0.2 % σ µ ± 350 / = 3.4 0.1 % σ µ ± 2 300 single channel single channel 1.5 250 single Kuraray single Ce:SiO 2 200 fiber bundle 1 150 100 0.5 50 0 0 300 400 500 600 700 800 900 80 100 120 140 160 180 200 220 240 260 280 Amplitude [ADC Count] Amplitude [ADC Count] σ /E=3.4% @ 100 GeV σ /E=6.1% @ 100 GeV F. Micheli et al., IEEE NSS 2015, San Diego (USA) Francesca Nessi-Tedaldi ETH Zürich 10

Energy resolution vs. energy ✦ Resolution with Ce:SiO 2 WLS fibres ✦ Dominated by the photoluminescent light yield, a factor ~10 lower than for Kuraray plastic fibers ✦ Higher light-yield fibres would improve the energy resolution Electron Beam Electron Beam 25 25 Energy Resolution [%] Energy Resolution [%] Data fibre 1 Data fibre 2 20 20 S = 54.58% 1.97 S = 25.94% 0.98 ± ± S = (26.0 ± 1.0)% S = (54.6 ± 2.0)% C = 2.45% 0.31 C = 2.12% 0.11 ± C = (2.1 ± 0.1)% ± C = (2.5 ± 0.3)% 15 15 single channel single channel 10 10 single Kuraray single Ce:SiO 2 fiber bundle 5 5 0 0 0 50 100 150 200 250 300 0 50 100 150 200 250 300 Beam Energy [GeV] Beam Energy [GeV] F. Micheli (ETH) et al., IEEE NSS 2015, San Diego (USA) Francesca Nessi-Tedaldi ETH Zürich 11