[PPT] - Double Chooz: The Show Goes On! Lindley Winslow University of PowerPoint Presentation

SLIDE 1

Double Chooz: The Show Goes On!

Lindley Winslow

University of California Los Angeles

On behalf of the Double Chooz Collaboration

SLIDE 2

The Double Chooz Collaboration:

Brazil CBPF UNICAMP UFABC France APC CEA/DSM/ IRFU: SPP SPhN SEDI SIS SENAC CNRS/IN2P3: Subatech IPHC Germany EKU Tübingen MPIK Heidelberg RWTH Aachen TU München

U. Hamburg

Tohoku U. Tokyo Inst. Tech. Tokyo Metro. U. Niigata U. Kobe U. Tohoku Gakuin U. Hiroshima Inst. Tech. Japan Russia INR RAS IPC RAS RRC Kurchatov Spain CIEMAT- Madrid USA

U. Alabama

ANL

U. Chicago

Columbia U. UCDavis Drexel U. IIT KSU LLNL MIT

U. Notre

Dame U. Tennessee Spokesperson:

H. de Kerret (IN2P3)

Project Manager:

Ch. Veyssière (CEA-Saclay)

Web Site: www.doublechooz.org/

SLIDE 3

Theory favored small sin22θ13!

Theory Order of Magnitude Prediction Le-Lμ-Lτ 0.00001 SO(3) 0.00001 S3 and S4 0.001 A4 Tetrahedral 0.001 Texture Zero 0.001 RH Dominance 0.01 SO(10) with Sym/Antisym Contributions 0.01 SO(10) with lopsided masses 0.1

Limit as

f 2011

Model Review by Albright et. al. ArXiv:0803.4176

Reactor Experiment Design Neutrino Factory Designs

SLIDE 4 Distance Probability 1.0 ~1000 meters P = 1 - sin22!13 sin2(1.27 "m2 L/E)!

Measuring the last mixing angle:

SLIDE 5 Distance Probability 1.0 ~1000 meters P = 1 - sin22!13 sin2(1.27 "m2 L/E)!

Measuring the last mixing angle:

Remember: We are looking for an effect as a function of L/E.

SLIDE 6

Construction Underway!

SLIDE 7

Double Chooz Analysis is Unique:

Analysis uses BOTH Rate and Energy information

➙Detailed Energy Response Model

Simple Reactor Configuration

➙ Multiple analysis periods.

Multiple Detector Phases - Now Far Detector Only

➙Detailed Reactor Model

SLIDE 8

Reactor Basics θ13 is Large! The Future

SLIDE 9 9

νe

Reactors Produce a lot of antineutrinos!

2×1020 νe per s per GWth

SLIDE 10

235U

νe νe νe

235U

140Xe 140Cs 140Ba 140La

νe

140Ce

νe

94Sr

νe

94Y 94Zr

An Example Fission:

SLIDE 11

Spectra per Fission ×

Obtaining the Neutrino Prediction:

Reactor core simulated with detailed inputs from the power company.

Fission Rates

Measured at devoted experiment at the ILL research reactor.

SLIDE 12

Fuel is arranged in assemblies. UO2 Fuel

Nuclear Reactor Basics

Fuel Assembly

SLIDE 13

We concentrate on SF97.

Takahama Benchmark

Published information of the irradiation history of fuel rods installed in a PWR

reactor. A chemical assay is performed

at the end of three fuel cycles. Fuel Assembly top 0m bottom 3.6m 0.16 m 0.35 m 0.6 m 1.8 m 3.5m 2.9 m

Six samples were taken along the rod. Fuel Rod SF97

SLIDE 14

Result of Takahama Benchmark for 235U:

Simulations agree with measurements and other codes within the uncertainties of the simulations’ inputs.

Phys. Rev. D 86, 012001 (2012)

SLIDE 15

Spectra per Fission ×

Obtaining the Neutrino Prediction:

Reactor core simulated with detailed inputs from the power company.

Fission Rates

Measured at devoted experiment at the ILL research reactor.

✓

SLIDE 16

Average Cross Section per Fission: Fractional Fission Rates

235U

0.496±0.016

239Pu

0.351±0.013

238U

0.087±0.006

241Pu

0.066±0.007

SLIDE 17

Normalization to Bugey-4:

The experiment with the smallest uncertainty, 1.4%.

SLIDE 18

Normalization to Bugey-4:

SLIDE 19

p

The Signal: Inverse Beta Decay

¯ νe

p n e+ Event #1 Ee = Eν - 0.8MeV Event #2 Eγ~8 MeV

30μs

Gd

SLIDE 20

7m 7m Target 10.3 m3 (8 tons) Gd Doped Scintillator Gamma Catcher 22.3 m3 Plain Scintillator Buffer 110 m3 Mineral Oil with 390 10” PMTs

SLIDE 21

Inner Veto 90 m3 LAB Scintillator with 78 8” PMTs 7m 7m

SLIDE 22

Outer Veto Precision muon tracking with plastic scintillator readout with fibers and multi- anode PMTs. 7m 7m

SLIDE 23

7m 7m Calibration Systems

Z-Axis
Guide Tube in Gamma Catcher
Light Injection (all volumes)
Buffer Tube
Articulated Arm

SLIDE 24

Last November’s Result: (DC1stPub)

Phys. Rev. Lett. 108 131801 (2012)

SLIDE 25

New Result: Double the Statistics! Improved Systematics!

Keep your eye on the ArXiv!

SLIDE 26

Selecting Antineutrino Coincidence:

Event #1

0.7 MeV < E < 12.2 MeV

Event #2

6.0 MeV < E < 12 MeV

2 μs < Δt < 100 μs time

SLIDE 27

Selecting Antineutrinos General:

p n

Event Quality Cuts (PMT Light Noise Cuts)
“Isolation in Time” Cut
Muon Veto, No coincident IV signal.
Muon Veto, 1ms following muon event.
Muon Veto, 500 ms following high energy

muon event (> 600 MeV deposited).

Muon Veto, No coincident OV signal.

These are new and reduce muon related backgrounds!

SLIDE 28 2011 Jul. 2011 Oct. 2012 Jan. 2012 Apr.

Data taking time (days)

50 100 150 200 250 300 350

Data taking efficiency

0.2 0.4 0.6 0.8 1 2011 Jul. 2011 Oct. 2012 Jan. 2012 Apr.

Data taking time (days)

50 100 150 200 250 300 350 Double Chooz (prel.) Total 1st result 2nd result

Collecting Data Since April 13, 2011... We see 8249 neutrino candidates in 227.9 live days.

SLIDE 29

Remember: Reactor Experiments are antineutrino disappearance experiments.

➜Background subtraction is key.

SLIDE 30

Neutrons Neutrons Neutrons

SLIDE 31

Neutrons Neutrons Neutrons

n

SLIDE 32

Some Basic Diagrams:

Target Veto Rock

SLIDE 33

μ

These neutrons we can veto...

Rock Veto

SLIDE 34

μ

Muons Passing through the Rock: These create two kinds of backgrounds: accidental and fast neutron.

Rock Veto

SLIDE 35 Day 50 100 150 200 250 300 )

1

Accidental Rate (day 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 Rate per day

Accidental Coincidences: R = 0.261±0.002 events per day

E (MeV) 2 4 6 8 10 12 Entries / 200 keV 1 10 2 10 3 10 Singles scaled Accidental prompt

SLIDE 36 Energy (MeV) 5 10 15 20 25 30 Entries/(0.25 MeV) 1 10 2 10 3 10 ) 2 (mm 2

1000

2000 3000 4000 3 10 ! z (mm)

2000
1000

1000 2000

Fast Neutron and Stopped Muons: R = 0.67±0.20 events per day

Prompt Event energy extends beyond reactor antineutrino spectrum. Fast neutrons are attenuated the center

f the detector while

stopped muons come down the chimney.

SLIDE 37

μ

These are very problematic... In addition to neutrons, muons can produce light isotopes. 9Li and

8He decay through β-delayed neutron emission.

Rock Veto

SLIDE 38 9Li Decay:

R = 1.25 ± 0.54 events per day after muon vetoes. Without the high energy muon veto would have been R = 2.05+0.62 -0.52 events per day.

Time to >600 MeV deposited Muon Background Subtracted Energy Spectrum

SLIDE 39

9Li

1.25±0.54

Fast-N + Stopped Muons

0.67±0.20 Accidental 0.261±0.002 Total 2.13±0.58 Candidates 36.2

Background Summary:

We have 1.6% uncertainty due to the backgrounds, but they can be constrained in a Rate + Shape analysis.

Events per Day

μ

SLIDE 40

Statistics 1.1% (1.6%) Reactor 1.7% Backgrounds 1.6% (3.0%) Detector 1.0% (2.1%) (compare to DC1stPub)

SLIDE 41

Energy Scale Improvements:

LED calibration system used to correct electronics non-linearity, and neutron capture maps to correct position dependence.

SLIDE 42 Visible Energy [MeV] 1 2 3 4 5 6 7 8 9 10 Entries per 0.50 MeV 100 200 300 400 500

Example Prediction:

No Oscillation sin22θ13=0.2

This analysis uses rates, energy information and two periods (1 reactor and 2 reactor).

SLIDE 43

Rate Only: sin22θ13 = 0.170 ± 0.035(stat) ± 0.040(sys)

SLIDE 44

Rate + Shape sin22θ13 = 0.109±0.030(stat)±0.025(sys) χ2/NDF = 42.1/35 sin22θ13 > 0 at 3.1σ !

SLIDE 45

Examining all of the data together.

SLIDE 46

Moving Forward!

SLIDE 47

Continued Analysis Work:

More Data
Continue to work on energy response model
Reactor model improvements
Add hydrogen captures to analysis
Improve background estimates

SLIDE 48

Now up to 8 days with both reactors off. Did I mention we get two Reactor Off Data?

SLIDE 49 prompt Energy (MeV) 2 4 6 8 10 12 Entries 0.5 1 1.5 2 2.5 3 DC2ndPub Background Reactor Off-Off data Total Background (Li9-reduced + OV) DC2ndPub Background Reactor Off-Off data Double Chooz Preliminary 2.2 ± Expected events: 12.8 Observed events: 8

After analyis cuts in 6.84 days of live time

bserved 8 events.

Nice agreement with 12.8±2.2 predicted for this period.

SLIDE 50

Test Result Stability in Time.... And look for Lorentz Violation. Lorentz violation in the neutrino sector implies the universe has a preferred direction. You can look for its effect by examining the

scillation probability as a

function of sidereal time. Strong limits for νe➙ νμ and νμ➙ ντ; however, there is an

pportunity to observe νe➙ ντ in reactor experiments.

See Kostelecký and Mewes PRD70(2004)076002

SLIDE 51

Test Energy Response and Background Levels.... ...and look for Double Beta Decay.

160Gd is a double beta decay candidate with an endpoint of 1.72

MeV. Double Chooz has the potential to improve the current limit if

background levels, especially those from U/Th are not too high.

Energy (MeV) 1 10

3

10

2

10

1

10 1 10 2 10 3 10 4 10 Data Sum Backgrounds K Target 40 U PMTs 238 Th PMTs 232 Rn Target 222 U to 238 Rn Chain Target 222 Pb Chain Target 210 Pb Target 210 Rn to 220 Rn Target 220 Th to 232 B 12 C 10 C 11

U n d e r C

n

s t r u c t i

n

!

SLIDE 52

Near Detector Under Construction:

Completed by the end of 2013.

SLIDE 53

0.5 -0.4 -0.3 -0.2 -0.1

0.1 0.2 0.3 Measurements 13 ! 2 2 sin

0.5 -0.4 -0.3 -0.2 -0.1

0.1 0.2 0.3 Double Chooz Jun. 2012 Double Chooz Nov. 2011 Daya Bay Mar. 2012 RENO April 2012 T2K (2011) Normal hierarchy T2K (2011) Inverted hierarchy MINOS (2011) Normal hierarchy MINOS (2011) Inverted hierarchy

Conclusions:

Double Chooz updates its

rate and shape analysis with improved statistics and systematics.

Double Chooz excludes

null oscillation hypothesis at 99.9% (3.1σ).

Double Chooz’s simple

reactor configuration allows for unique analyses.

SLIDE 54

The Chooz Goes On!

SLIDE 55