Double Chooz Experiment Status Double Chooz Experiment Status Jelena - PowerPoint PPT Presentation

Double Chooz Experiment Status Double Chooz Experiment Status Jelena Maricic, Drexel University (for the Double Chooz Collaboration) (for the Double Chooz Collaboration) 27 th SNAC11 September, 27 th , SNAC11 S t b

Double Chooz Collaboration

Outline • Neutrino detection and  13 measurement • Overview of the Double Chooz O i f th D bl Ch detector • DC far preliminary data • Antineutrino anomaly and consequences for Double Chooz • Summary and outlook

NEUTRINO DETECTION AND  13 MEASUREMENT

Reactor Neutrino Detection Signature • Reactors as neutrino sources:   6 N    6 N Fiss s  1      2  10 11 P s  1     N  s  1 1 1 2 10 11 P 1 N Chooz: P =2x4.25 GW th  N  ~2x10 21 s ‐ 1  th Neutrino detection via inverse  decay Target: g Distinctive two ‐ step signature: Gd doped ‐ prompt event scintillator Photons from e + annihilation Photons from e annihilation E e = E   + 0.8 MeV + O(E e /m n ) ‐ delayed event 1 g/l Gd Ph t Photons from n capture on f t in LS dedicated nuclei (Gd)  t ~ 30  s E ~ 8 MeV Gadolinium Gadolinium 5 J. Maricic ‐ Double Chooz

Site in French Ardennes 300 mwe Hill topology East Reactor Started 12/10 West Reactor West Reactor Physics data taking 04/11 351 m France 465 m 115 mwe Flat topology Start in early 2013 Jelena Maricic, Drexel U 6

The ‐ New – Concept – 2 detectors P(  e   e ) = 1 ‐ sin 2 (2  13 ) sin 2 (  m 2 ( e e ) ( 13 ) ( 31 L/4E) 31 / ) Background reduction Background reduction and calibration are very important E = 1 ‐ 8 MeV Pure  e flux  e  e,µ, τ  e,  ,  Nuclear Power Station Far detector Near detector 400 m 1050 m Far to near detector signal ratio will give information about θ 13 Jelena Maricic, Drexel U 7

Expected Neutrino Oscillation Signal Two independent sets of information: Two independent sets of information: Normalisation + Spectrum distortion sin 2 (2  13 )=0 04 sin (2  13 )=0.04 ars Far/Near ratio Far/Near ratio ents/200 KeV/3 yea sin 2 (2  13 )=0.1 sin 2 (2  13 )=0.2 Eve E (MeV) F Far Detector: ~ D t t ~ sin 2 (2  13 )=0.12  m 2 atm = 3.0 10 ‐ 3 eV 2 40 000events/3y ‐ Reactor efficiency: 80% ‐ Detector efficiency: 80% E (MeV) Near Detector: ~ 5 10 5 events/3y ‐ Reactor efficiency: 80% Reactor efficiency: 80% arXiv: hep ‐ ex/0606025v4 ‐ Detector efficiency: 80% ‐ Dead time: 50% 8 J. Maricic ‐ Double Chooz

4 concentric vessels 7 m 7 m Neutrino target vessel l in the center http://doublechooz.in2p3.fr/ 7 m J. Maricic, Drexel U 9 Courtesy of T. Lasserre

The detector design Near and far detectors are IDENTICAL. Muon Outer ‐ VETO : 7 m  ‐ target : 80% dodecane + 20% PXE + 0.1% Gd Volume for  ‐ interaction (d = 2.3 m, h = 2.8 m)  ‐ catcher : 80% dodecane + 20% PXE Extra volume for  interaction Extra ‐ volume for  ‐ interaction 511 keV 7m Acrylic vessels  «hardware» 511 keV definition of fiducial volume p  e e + n Gd Gd Non ‐ scintillating buffer : same liquid Isolate PMTs from target  ~ 8 MeV Muon Inner ‐ VETO : scintillating oil (78 8”PMTs) Shielding : steel 17 cm: >7   Improved background reduction PMT support structure: steel tank, optical insulation target/veto area (390 10” Jelena Maricic, Drexel U PMTs) 10

Inner Detector

Inner Detector Lid

Background in Double Chooz Accidental bkg : • e + ‐ like signal: radioactivity from • e ‐ like signal: radioactivity from materials, PMTs, surrounding rock Rate=R e • n signal: n from cosmic  spallation • n signal: n from cosmic  spallation, thermalized in detector and captured on Gd (R n )  Accidental coincidence  Accidental coincidence Rate = R e x R n x Δ t Correlated bkg : • fast n (by cosmic  ) recoil on p (low energy) and captured on Gd • long ‐ lived ( 9 Li, 8 He)  ‐ decaying isotopes induced by  Jelena Maricic, Drexel U 14

Calibration CHOOZ had a 1 6% absolute detector systematic uncertainty the best to date Total CHOOZ had a 1.6% absolute detector systematic uncertainty, the best to date. Total uncertainty 2.7% Bugey is the only experiment that has tried to build identical detectors. Result was 2.0% relative error. 5.0% total. Double Chooz goal is 0.6% relative uncertainty and less than 0.6% total. D bl Ch l i 0 6% l i i d l h 0 6% l Calibration sources: Glovebox Glovebox ‐ Natural H n ‐ capture peak ‐ Radioactive sources ‐ Laser and LED system Fish ‐ line Buffer guide tube Gamma ‐ catcher Articulated Arm guide tube Deployed in NT and GC: 137 Cs, 60 Co, 68 Ge, 252 Cf LED system

Calibration ‐ 68 Ge in the guide tube Calibration Ge in the guide tube Blue – MC Red ‐ data Example of calibration data: 68 Ge in the guide tube. g Monte Carlo tuning is ongoing.

DC FAR PRELIMINARY PHYSICS DATA DC FAR PRELIMINARY PHYSICS DATA

Data Taking • Data taking with far detector started on April 13, 2011 • >100 days y physics data • Trigger rate ~120 Hz Hz • Trigger threshold < 0.6 MeV • 75% physics runs h • 10% calibration runs

Muons: rate and coincidence Muons: rate and coincidence • Inner veto 39 Hz • Michel electrons from stopped muons: stopped muons: • Inner detector 11 Hz • Inner detector 11 Hz •  = 2.25  0.13  s  t = time between 2 muons in ms T ID – T OD =  t = time in  s

Muon correlated events Muon correlated events • H ~ 2.2 MeV • C ~ 3 ‐ 5 MeV C 3 5 MeV • Gd ~ 8 MeV • Energy calibration is ongoing ongoing

Muon correlated neutron capture on H Muon correlated neutron capture on H • Muon Stable for 120 days correlated Rate < 0.1 Hz neutron capture in capture in hydrogen energy window • 1.9 – 2.5 MeV

Neutrino candidates selection Neutrino candidates selection 1) Apply muon veto cut ~1 ms 1) Apply muon veto cut 1 ms 2) Prompt energy window 0.7 – 12 MeV ‐ singles rate ~10 Hz ‐ singles rate 10 Hz 3) Delayed energy window 6 – 12 MeV ‐ singles rate ~0.1 Hz i l t ~0 1 H 4) Coincidence window ~ 100  s Result: neutrino candidates (neutrinos + bkg)

Time and Space Distribution • Timing distribution Timing distribution between prompt and delayed signal in Gd energy window (6 ‐ 12 i d (6 12 MeV)   ~ 30  s. • Spatial distribution between prompt and d l delayed signal – between d i l b 20 ‐ 30 cm is expected.

Energy spectrum in delayed Gd window • Energy distribution of delayed signals in the Gd energy window (6 ‐ 12 MeV)  peak ~ 8.3 MeV

Position Reconstruction of neutrino candidates – delayed signal vertex d d d l d l Gd doped Gd doped p target target Detector top view Detector side view Gamma catcher

Daily Neutrino Rate Daily Neutrino Rate 1 reactor off data ~4000 neutrino candidates in 3 months  already exceeds CHOOZ statistics

Summary and Outlook • Double Chooz is detecting neutrinos g • Backgrounds are low • We will use Bugey ‐ 4 c ‐ s for normalization • Data analysis in progress progress Near detector • T2K best fit will be addresses with this data set