Calorimetry (high precision @ LSD) FroST16 workshop FNAL, Chicago - PowerPoint PPT Presentation

Calorimetry (high precision @ LSD) FroST16 workshop FNAL, Chicago USA — March 2016 Marco GRASSI (IHEP , China) Anatael Cabrera CNRS / IN2P3 APC Laboratory (Paris, FR) LNCA Underground Laboratory (Chooz, FR)

today’s LSD detectors… 2 today neutrino detectors (historical ordering) … LSD: transparent & “large” PMTs • Liquid Scintillator [ LSD ] (ex. Double Chooz, KamLAND,etc) • Water Cherenkov (ex.Super-KamiokaNDE, etc) • Liquid-Argon TPC (ex. ICARUS, etc) Liquid Scintillator detector (LSD) features… simple ✓ signal transparent* ✓ energy ( → excellent) homogenous* ✗ background: no event-by-event ID large size* largest LSDs: KamLAND & SNO+ •radioactivity purity composition (# protons) ↳ long & very expensive process •shielding & underground ↳ even up to ~50% cost ( → even more, if new underground lab needed) ✗ no doping or little ( few % or ‰ ) [ → limited physics programme ] ✓ cost (driven by PMT) energy measurement irreducible BG characterisation and/or subtraction •the name of game is more light & resolution (not just light) •low energies range (<MeV) and/or better calorimetry ~1k ton LSD @ ~2km underground ⇒ this talk: a 2 topics (first time presented) on high resolution calorimetry Anatael Cabrera (CNRS-IN2P3 & APC)

LSD calorimetry in action… 3 LSD signal ⊕ BGs rate+shape simultaneous measurement •thanks to energy resolution & linearity (i.e. calorimetry) • irreducible BGs → only way to handle (if lucky) Borexino (solar ν ’s) KamLAND-ZEN phase-1 (2 β 0 ν signal) Double Chooz (reactor ν ’s) [DC-IV: θ 13 & 8 Li+ 9 He measured at once] Anatael Cabrera (CNRS-IN2P3 & APC)

LSD’s PID in action (example PSD)… 4 LSD’s ability PSD ability (very limited → little pattern recognition) depends light level •even if calorimetric is poor (due to dominant non-stochastic terms) • better if high precision calorimetry is possible → likely better PID Anatael Cabrera (CNRS-IN2P3 & APC)

a necessary but not sufficient condition…light! 5 an LSD logic γ electronics electronics pe γ λ atte ≤ 25m λ scat ≥ 10m PMT electronics wavelength-shifter ( → fluors) better PMTs Energy → γ (scint) → γ (ws) → pe’s → (charge,time) (more PEs) Liquid Scintillator ~10,000 γ /MeV → ≲ 1% resolution some fraction light loss → >1% resolution PMT detection efficiency (~30%) → ≳ 2% resolution charge digitisation (bias, non-linearities, etc) → ~3% resolution double calorimetry how about response systematics? (better systematics) Anatael Cabrera (CNRS-IN2P3 & APC)

6 better PMTs… (more & higher quality light) Anatael Cabrera (CNRS-IN2P3 & APC)

11" ETEL PMT ETEL Development of 11 15 prototypes produced inch PMT started in 2013 and tested at Penn, UC for LBNE Davis and Drexel. Barros et al (including Svoboda) @ arXiv:1512.06916v2 7

envelop made with Schott • 8250 glass tube instead of EU glass discolored spot due to the • manufacturing process – corrected in later version • characterisation of initial trigger ETEL PMT batch corrects for this • 12 dynode structure: 10 7 @ ~1300V (nominal) TTS: 1.8ns (RMS → ?) • ETEL-11-PMT SPE Charge Spectrum ETEL-11-PMT SPE Time Spectrum 8

charge: 11-inch similar 12-inch timing (TTS): 11-inch worse 12-inch ⇒ lower operating voltage may play into this (~1300V as opposed to ~2000V) 9

Relative Efficiency Quantum x Collection Efficiency per cm 2 comparable to Hamamatsu 12-inch and 10-inch HQE PMTs 10

(within JUNO) new 20” MCP based PMT… 11 • 20” PMT (but also 8”) developed in China • increase in effective detection efficiency (comparable to Hamamatsu20”) → increase of light level is highest priority → large peak-to-valley (SPE efficiency) • TTS ~10ns not best (location of MCP) → JUNO hybrid system with other PMTs @JUNO decision … •15,000 MCP-PMT 20” •5,000 Hamamatsu PMT 20” Anatael Cabrera (CNRS-IN2P3 & APC)

12 control of systematics… (i.e. non-stochastic effects) Anatael Cabrera (CNRS-IN2P3 & APC)

JUNO location… 13 simplistic schedule: data-taking by 2020 Anatael Cabrera (CNRS-IN2P3 & APC)

14 ~18,000 PMTs (20” diameter) → Large-PMT system ( LPMT ) ~36,000 PMTs (3” diameter) → Small-PMT system ( SPMT ) Anatael Cabrera (CNRS-IN2P3 & APC)

15 largest photo-cathode density ever built ⇒ highest precision calorimetry ever built largest light level ever detected ~1200PE/MeV ⇒ stochastic resolution <3% @ 1MeV control of non-stochastic resolution extremely demanding → ≲ 1% (driven by SPMT) Anatael Cabrera (CNRS-IN2P3 & APC)

our (very international) team… 16 >15 laboratories so far… Brasil •FABC (Sao Paulo) •PUC (Rio de Janeiro) Belgium •UBL (Brussels) Chile •PUC (Santiago) China •IHEP (Beijing) •SYSU (Guangzhou) France •APC (Paris) (coordination) •CPPM (Marseille) •LLR (Paris) •OMEGA (Paris) •SUBATECH (Nantes) Italy •Padova-INFN (Padova) Taiwan •National Taiwan University NTU (Taipei) •National Chiao Tung University NCTU (Hsinchu) •National United University NUU (Miaoli) A few more institutions joining … Anatael Cabrera (CNRS-IN2P3 & APC)

17 motivation… — why the SPMT? — Anatael Cabrera (CNRS-IN2P3 & APC)

DC as prototype for JUNO… 18 control of response stability control of response uniformity after stability calibration 1.06 Variation 1.05 n-H captures (BiPo poor stats) 1.04 BiPo212 1.03 n-Gd captures 1.02 RMS=0.35% 1.01 ±1% 1.00 0.99 0.98 DC-III (Gd-n) Preliminary 0.97 0 100 200 300 400 500 600 700 Elapsed Days Energy Resolution DC: ~200PE/MeV 0.14 data 0.12 MC 137 Cs 0.10 volume source (data) 68 Ge 0.08 volume source (MC) 252 H ( Cf) 0.06 C (GC, spall. n) 60 Co 252 Gd ( Cf, ) ν 0.04 DC with 1200PE/MeV 0.02 DC-III (Gd-n) Preliminary 0.00 0 1 2 3 4 5 6 7 8 9 Visible Energy (MeV) non-stochastic terms (i.e. b & c): very sensitive to high energy level arm (understood?) Anatael Cabrera (CNRS-IN2P3 & APC)

no perfect world… 19 σ (E) 2 = σ (E) 2stoch + σ (E) 2non-stoch ⟹ empiric formulation: (1200PE/MeV) (??%) JUNO* [1.2kPE/MeV only stochastic] JUNO* [non-stochastic: a la DC] JUNO* [non-stochastic: half DC] ~1.2k PEs JUNO* [non-stochastic: “negligible”] σ (E) stoch < 3% JUNO* the impact of σ (E) non-stoch JUNO* JUNO* dominates!! JUNO* Visible Energy (MeV) •if perfect light measurement: σ (E) 2non-stoch → 0 (i.e. LS ⊕ PMT ⊕ electronics no dispersive effects ) •if perfect calibration: σ (E) 2non-stoch → 0 (i.e. perfect correction of dispersive effects ) (unfortunately) none is true!! Anatael Cabrera (CNRS-IN2P3 & APC)

the double calorimetry… 20 σ (E) 2 = σ (E) 2stoch + σ (E) 2non-stoch ( 1200PE @ 1MeV ) if σ (E) 2 ≤ 3.0% ⇒ σ (E) 2stoch =2.89% & + σ (E) 2non-stoch =0.82% (remaining) @DC: σ (E) 2non-stoch ≳ 2% now consider ( 1200±50)PEs @ 1MeV (same condition as before) ⇒ ≥ 1300PE/MeV • +50PEs implies σ (E) 2stoch =2.83% & + σ (E) 2non-stoch =1.00% (remaining) ~2x ( →σ non-stoch ≥ 1.0%) • -50PEs implies σ (E) 2stoch =2.95% & + σ (E) 2non-stoch =0.55% (remaining) small difference in light level (>1150PE/MeV) ⇒ major impact to σ (E) 2non-stoch : most challenging!! response uniformity “double-calorimetry” Response (normalised @ ⊙ ) articulate 2 energy estimators (different behaviours) Response(QI) Response(PS) Energy(photon-counting) i.e. digital ( PS ) Energy(charge integration) i.e. digital ( QI ) ⇒ E(response,x,y,z) DC = E(PS) ⊕ E(QI) [via NN, correction, etc] ρ position (mm) control/reduction σ (E) 2non-stoch & redundancy [if ± Δ m 2 → convince JUNO can ] Anatael Cabrera (CNRS-IN2P3 & APC)

the JUNO challenge… 21 @1MeV λ ⦿ = mean illumination per channel @ center mean illumination per channel (PE/PMT) Bx DC DB KamLAND JUNO 2212PMTs 390PMTs 190PMTs 1880PMTs 17000PMTs ~500PE/MeV ~180PE/MeV ~180PE/MeV ~250PE/MeV ~1200PE/MeV ~100x NT GC ~3x ( λ ⦿ ≈ 1.0) ~2x ~4.5m buffer ( λ ⦿ ≈ 0.28) ( λ ⦿ ≈ 0.35) ≤ 4x ≤ 4x SPMT LPMT ( λ ⦿ ≈ 0.13) if λ ≲ 0.5 ⇒ ~photon-counting regime ( λ ⦿ ≈ 0.07) HIGHEST precision calorimetry ( ≤ 3% @ 1MeV) ⊕ LARGEST dynamic range in calorimetry (channel-wise) [ ⇒ uniformity ⊕ linearity ⊕ stability ] Anatael Cabrera (CNRS-IN2P3 & APC)

PS vs QI in action… 22 response stability 0.05 α DC-III (data) Double Chooz Preliminary ∆ 0.04 0.03 0.02 0.01 0.00 -0.01 -0.02 -0.03 -0.04 -0.05 0 100 200 300 400 500 600 Elapsed Days “digital” response stability @ 2.2MeV (zero tracking ⊕ other effect) (invisible to charge integration estimator alone) Energy(PC) & Energy(QI) are highly complementary!! Anatael Cabrera (CNRS-IN2P3 & APC)