Christian Buck, MPIK Heidelberg for the Double Chooz Collaboration LAUNCH March 23rd, 2007 The...

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Christian Buck, MPIK Heidelberg for the Double Chooz Collaboration LAUNCH March 23rd, 2007 The Double Chooz experiment

Transcript of Christian Buck, MPIK Heidelberg for the Double Chooz Collaboration LAUNCH March 23rd, 2007 The...

Christian Buck, MPIK Heidelberg for the Double Chooz Collaboration

LAUNCH

March 23rd, 2007

The Double Chooz experiment

Outline

Motivation

The Double Chooz Concept and Design

Scintillator development at MPIK

Summary

Why Double Chooz?

Improved knowledge of mixing matrix

Θ13 controls 3 flavor effects (e.g. CP violation only for Θ13 > 0)

Discovery potential: models often close to experimental bound

Complementarity to beam experiments

- Degeneracies + parameter correlations

- Optimize future experiments

Discrimination power for normal hierarchy in 0νββ depends on Θ13

Δmsol2 ~ 8∙10-5 eV2, sin2(2Θ12) ~ 0.86

Δmatm2 ~ 2.5∙10-3 eV2, sin2(2Θ23) ~ 1

ν2

Δmatm2

Δmsol2 ν1

ν3

sin2Θ13

sin2Θ23

sin2Θ12

νe

νμ

ντ

ν eν μν τ =U e1 U e2 U e3Uμ1 Uμ2 Uμ3U τ1 U τ2 U τ3

ν 1

ν 2

ν 3

Interest of International Atomic Energy Agency (IAEA) in νe detection

- Monitoring of single reactors

- Monitoring of countries

Intensity and shape of spectrum depend on isotopic composition Pu content!

Use Double Chooz near detector as prototype for reactor monitoring

Thermal power (1% ?)

Non-proliferation

Current proposals

December 2002: 1st European meeting, MPIK April 2003 – February 2005: 4 int. workshops in U.S., Germany, Japan and Brazil 1st Double Chooz Meeting: Nov 2003

Angra

Double-Chooz

KaskaDaya bay

RENO

Double Chooz collaboration

Spokesman: H. de Kerret (APC) France: CEA/Dapnia Saclay, APC, Subatech (Nantes) Germany: MPIK Heidelberg, TU München, EKU Tübingen, Universität

Hamburg, RWTH Aachen Italy: LNGS (Gran Sasso) Russia: RAS, Kurchatov Institute (Moscow) USA: Alabama, ANL, Chicago, Drexel, Kansas State, LLNL, LSU, Notre

Dame, Tennessee Spain: CIEMAT Japan: HIT, Kobe, MUE, Niigata, Tohoku, TGU, TIT, TMU England: University of Oxford

The Double Chooz concept

ν ν νν

ννν

ν 1051 m280 m

Site location: FranceDnear Dfar

The labs

Far detector (300 m w.e., 1.05 km) Near detector (75 m w.e., 280 m)

Δm2atm = 2.8·10-3 eV2

(MINOS best fit)

Constant flux ratios

Improving Chooz

0.3 %1.5 %Det.eff.

< 0.6%2.7 %Σ system.

0.4%2.8%Statistical

0.2 %0.8 %# protons

<0.1 %0.7 %Power

<0.1 %0.6 %E/fission

<0.1 %1.9 %Flux, σ

DCChoozerror

CHOOZ limit

sin2(2θ13) < 0.12 – 0.20R = 1.01 2.8%(stat)

2.7%(syst)

Reactor

Detector

ν e ν x

Δm

2 (eV

)2

sin2(2Θ)

10-2

10-3

Sensitivity

2008

Sensitivity 2008 – 2013 (near detector starts 16 months after far) for m2

atm = 2.8·10-3 eV2

Detector design

TARGET: (th = 2,3m)- Acrylic vessel (th = 8mm)

- 10,3 m3 LS (1 g/l Gd)

γ-catcher: (th = 0,55m) -Acrylic vessel (th = 12mm)

- 22,6 m3 LS

Buffer: (th = 1,05m) -Steel vessel (th = 3 mm)

-114 m3 mineral oil

Inner veto: (th = 0,5m) -Steel vessel th = 10 mm)

-~80 m3 LS

SHIELDING (th = 17 cm)- Steel

7m

7m

Neutrino signal

n

e

p511 keV

511 keVe+

~ 8 MeV

Gd

Target: Gd-loaded liquid scintillator

Eve

nts/

200

KeV

/3 y

ears

sin2(213)=0.04 sin2(213)=0.1 sin2(213)=0.2

Energy [MeV]

Neutrino rates: - far: ~70/day- near: ~1000/day

Correlated backgrounds

n

~ 8 MeV

n deposits energy

Gd

Fast neutrons

Chooz rate: ~1/day

Double Chooz simulation:

Far: Nb < 0.6/day (90% CL)

Near: Nb ~ 3.3/day (90% CL)

β-n-cascades (spallation products: 9Li, 11Li, 8He)

Expected rate:

Far: 1.4/day, Near: 9/day

Long-lived

Mockup

Goal:

- Find technical solutions

- Define interfaces

- Material compatiblity

- Test filling procedure

Volumes:

- 100 liter Target

- 200 liter Gamma Catcher

- 700 liter Buffer

Match scintillator properties:

- Densities (1 % in DC)

- Light yield

Filling system

Simultaneous filling

Air driven pumps

Tubing and valves PFA

Filling 2005

MPIK-HD

Mockup results

400 420 440 460 480 500 520 540 560 580 6000,000

0,005

0,010

0,015

0,020

0,025

0,030

0,035

0,040

0,045

0,050Target

5 m

Abs

orba

nce

wavelength [nm]

Dec 05 Jan 06 Feb 06 Mar 06 Apr 06

400 420 440 460 480 500 520 540 560 580 6000,000

0,005

0,010

0,015

0,020

0,025

0,030

0,035

0,040

0,045

0,050-catcher

Dec 05 Jan 06 Feb 06 Mar 06 Apr 06

5 m

Abs

orba

nce

wavelength [nm]

0 1 2 3 4 50,0

0,1

0,2

0,3

0,4

0,5

0,6

0,7

0,8

0,9

1,0Target

Gd-

conc

. [g/

l]

months

Gd-concentration unchanged

Optical properties stable

Metal loaded scintillators

Development at MPIK since 2000 (C.Buck, F.X.Hartmann, D.Motta, T.Lasserre, S.Schönert, U.Schwan)

Wide interest in different fields:- Solar neutrino physics (In, Yb,…)

- Reactors experiments (Gd)

- Geo-neutrinos (Gd)

- 0νββ-decay (150Nd)

400 425 450 475 500 525 550 575 600 625 6500

5

10

15

20

25

mo

l.ext

.[l/(

mo

l*cm

)]

wavelength [nm]

Nd(acac)3nH

2O

NdCl3

Scintillator development at MPIK

Metal-β-diketonates:R1

3+M

R2

O

OO

O

O

O

HC-

C-

H

C-H

R1 R1

R2

R2

How to dissolve metal in organic scintillator? Method 1: Organometallic compound

Requirements: solubility no light quenching optical transparency radiopurity low reactivity (stability!)

Method 2:

Carboxylate system stabilized by pH (since 2000)

Attenuation length / stability

380 400 420 440 460 480 500 5200

10

20

30

40

50

60

70

80

90

100

atte

nuat

ion

leng

th [m

]

wavelength [nm]

solvent Gd-solution final scintillator

Stability tests up to 3 years

Tests of concentrates

Temperature tests

Cross check in Saclay

Measured by UV/Vis

10 cm cells

Absorption + Scattering!

No fluors: > 10 m in ROI

ROI

Scintillator stability

Palo Verde:

A.G.Piepke, S.W.Moser, V.M.NovikovNIM A 342 (1999) 392-398

Chooz: Time variation fit of attenuation length:

L att t =L 0

1 v⋅t

Parameter v

Chooz: (4.2 ± 0.4)∙10-3 /d *

BDK-system: ≤ 7.5∙10-5 /d

* Chooz Coll., Eur. Phys. J. C27, (2003) 331-374

[v = (1.5 – 2.8)·10-3 /d)]

Scintillator system

Excitation by ionizing particle

PMT

Metal

Secondary wavel. shifterFluorsolvent

Gd complex

0 500 1000 1500 2000 2500

0,02

0,04

0,06

0,08

0,10

0,12

0,14

coun

ts/(

h*kg

*keV

)

Energy [keV]

Approach: Gd-β-diketone

Purification by sublimation

Full scale production started!

8·10-108.7·10-13< 2.4·10-13Conc.[g/g]

0.25 0.032 < 0.03A/det. [Bq]

0.00065

Th

0.005< 0.0006A/kg

[Bq]

K U

GeMPI at LNGS (M.Laubenstein)

Scintillator solvent

PXE/dodecane mixture (20/80 Vol):

Optimized ratio

- PXE improves light yield

- Dodecane improves material compatibility + number of H

Column purification

High flash point, low toxicity

Solvents used in KamLand (Dodecane), Borexino (PXE in CTF)

Backup Linear alkylbenzene

350 400 450 500 550 600-0,0020,0000,0020,0040,0060,0080,0100,0120,0140,016

abso

rban

ce

wavelength [nm]

unpurified b1 unpurified b2 purified

10 m

Fluor choice

Primary fluor properties:

Light yield

Emission spectrum

Energy transfer parameters

Transparency

Radiopurity 380 400 420 440 460 480 500 520 540 560 580 6000

100

200

300

400

500

600

700

light

inte

nsity

[a.u

.]wavelength [nm]

Scintillator emission spectrum

Energy transfer model

0 20 40 60 80 1000

10

20

30

40

50

60

70 2 % In 5 % In

Ligh

t yie

ld [%

BC

505]

Fluor concentration [g/l]

I c , q = I 0⋅1

1 k s⋅c⋅

11K⋅q /c

0 10 20 30 40 500

10

20

30

40

50

60

70

80

90

100

rel.

light

yie

ld

Indium [g/l]

M

D A*excitation

.

.. . ..M

.........

.M

M

O

CH

I n

OO

O

O

O

Me .

C.Buck, F.X.Hartmann, D.Motta, S.Schönert, Chem.Phys.Lett.435 (2007) 252 – 256

Developed for Indium system

Scintillator Summary

2000 – 2003: Development metal loaded scintillator (In, Yb, Nd, Gd)

2003: First tests Gd-loaded scintillators– Gd(acac)3 scintillator

– pH controlled carboxylate (TMHA) scintillator

2004: Optimization synthesis 2005: Double Chooz mockup 2006: Outsourcing of Gd-BDK production

– Successful sublimation at company– First radiopurity measurements

Summer 2006: New division

3 x 24m3 Iso-containers Large scale production Gd-material

Scintillator building

60 m³ liquids

Scintillator hall

Dec 06 Jan 07

Feb 07 Mar 07

Summary

Double Chooz searches for the neutrino mixing angle θ13

- Sensitivity: sin2(2Θ13) < 0.02 - 0.03 (90% CL) (Chooz bound sin2(2Θ13) < 0.2)

- Start data taking: 2008

Main hardware contribution of MPIK:

- Development + production target Gd-scintillator (10.3 m³)

- Tuning + production of γ-catcher scintillator (22 m³)

- Design and construction scintillator mixing system

Status

- Major components ordered

- Construction of scintillator hall