física de neutrinos de reatores - cbpfrenafae/workshops/2012/dia-1/report-dchooz_nov20… · •...

Física de Neutrinos de Reatores:

Experimento Double ChoozEstudos de Propriedades Fundamentais dos Neutrinos

Experimento Neutrinos AngraAplicações e novas tecnologias

J. C. Anjos Workshop RENAFAE – 2012

CBPF, 29 Nov. 2012

Current Status of the Neutrinos Angra Experiment:

Monitoring nuclear reactors with antineutrino detectors

29/11/12 3

New challenge: neutrino detection above ground

Angra Neutrino laboratory: 40’ container

J.C.Anjos-RENAFAE 2012

29/11/12 4

CBPFJ.C. Anjos, G.L. Azzi, H. Lima Jr, M. Vaz,

Collaborators: Aridio Schiapazza

Rogério M. da Silva

Graduate Students: Marcelo Nascimento Souza (PhD) Thamys Abrahão (MSc)

Marcio Nunes (PhD) Rafael Gama (PhD)

Undergraduate Students: Upiratan Machado (UERJ) Beatriz Santos (UERJ)

Igor Oliveira (IME)

Brazilian Institutions:

ANGRA Collaboration:


29/11/12 5

5

ANGRA Collaboration:

PUC-RJHiroshi Nunokawa

UNICAMPE. Kemp, T. Bezerra, L. F. González,

L. M Santos

UFBAIuri M. PepePaulo Farias

UEFSGermano P.

Guedes

UFABC Marcelo Leigui, P. Chimenti

UFJF Luciano M. Andrade, Rafael A. Nóbrega,

Augusto S. Cerqueira

UnifalGustavo

Valdiviesso


29/11/12 6

Motivations for ANGRA

• Very interesting for the Brazilian science:

– Possibility to start an experimental neutrino physics program in Brazil taking advantage of existing antineutrino sources (Angra-I and II nuclear reactors).

– Possibility to do neutrino applied physics: . nuclear safeguards applications. . new detector technologies.

– Develop know how in experimental neutrino physics to be used in future projects.


29/11/12 7

Nuclear Safeguards Applications

ANGRA PROJECT:


29/11/12 8

Why IAEA may have interest in antineutrino detectors?

• Antineutrinos can not be shielded and are produced in very large amounts in nuclear reactors (~ 1020 antineutrinos/s)

• Antineutrinos coming from different isotopes have different energy spectrum: antineutrino measurement may reveal, in principle, fissile composition of nuclear fuel.

• Non-intrusive, Real Time, Remote reactor monitoring: thermal power & fissile material

• Search for new methods on safeguards verification


29/11/12 9

International Cooperation CNEN/DOE2012 Agreement


29/11/12 10

International Cooperation CNEN/DOE2012 Agreement


29/11/12 11

Angra detector facts: Water Cherenkov

Prompt signal:Positron1 ~ 12MeV

Delayed signal:γ’s from neutron captureon Gd: 8MeV

Time interval:Δt ~ 30μsec

Reactor power: 4 GWthTarget mass: 1 tonDetector distance to core: ~25 metersInverse beta decay interactions per day: ~5,000


29/11/12 1212

New Detector Design

Detector design (2011)

(detector + muon veto)

Central detector: water tank with 32 PMTs to detect Cherenkov radiation

external water shieldTs


29/11/12 13

The neutron detector: 260 l prototype for neutron detection in Gd loaded water ( 1 PMT)

•252Californium Source arrived at CBPF in June 2012

•Instalation of a small laboratory in the old CBPF linear accelerator tunnel;

•Authorization to use the neutron source given by CNEN in 2011;

•Instalation of water purification station concluded;•Experimental measurements started with pure

water:•Calibration with Cosmic muons finished;•Next step: add Gadolinium in the water


29/11/12 14

ELECTRONICS STATUS


29/11/12 15

Front-end electronics

VME bus

PMT

ADC125 MHz

trigger logic

control and status registers

data builder

TDC81 ps

28 bitsstop

start*

time encoding

FPGAs

* trigger pulse from previous event

leading-edgediscriminator

control dataaddr

signal conditioning

10 bits

FIFO

DC level-1trigger

Eletronics Design - (conceptual diagram 2007)

DAQ diagram


29/11/12 16

VME 6U Board: DAQ: waveform digitizer+ time stamp

• Lay-out of VME board developed in collaboration

with Brazilian industry CADSERVICE

• Components mounted by CADSERVICE

(Campinas, SP)

Eletronics Design - (present status 2012)


Data Acquisition

Data readout (software)

ü Readout software code developped in C and ADA

ü 3 fully working systems, each one with one ROPs + NDAQs (2 at CBPF e 1 at Unicamp)

ü Last firmware and DAQ software version is very stable, working without problems for few days continusly in lab tests.

ü All software is SVN version controled.

ü Last implemented code has a check of the serial number and firmware version at the startup in the DAQ-level.

Front-end Electronics - UFJF

ü 4 stages operational amplifier

ü 8 channels circuit using NIM standard module.

ü 5 boards (PCB) built in July/2012 and are now been mounted.

29/11/12 19

Luciano M. de A. Filho (UFJF)

Augusto Santiago (UFJF)A. F. Barbosa (CBPF)

Optimized Digital Detection for the Trigger System.


29/11/12 20

Proposal

20

DigitalFilter

TriggerDecisio

n

Central FPGA of NDAQ

ADC

•Digital Filter to maximize signal/background ratio before the trigger.

•Implementation → Filter FIR.

•Two methods tested

1. Matched Filter.

2. Optimized Filter for amplitude estimate.

•Similar results for both filters.

•Optimized filter has advantage of output in Volts.

Increase signal/backgroun

dratio


29/11/12 21

Results

21

Peak/Valley = 2.5

Peak/Valley = 5.0

Variance of the measurement:

Error in the measurement:

ANTES DEPOIS


29/11/12 22

Detector Simulation Studies


29/11/12 23

Data Analysis: simulation of expected signal and

background Signal and background Simulation:

• Positrons (from neutrino interaction)• Neutrons (from neutrino interaction)• Cosmic ray induced background


24

Signal and cosmic background frequency

Table 1: Particles from antineutrino signal

Table 2: Particles from cosmic background

Particles Frequency (HZ)

Muons 210±6

Neutrons 20±1

Protons 2.0±0.2

Pions 0.40±0.01

Photons (8 ± 1)×103

Positrons 257±61

Electrons 242±140

Particles Frequency (HZ)

Positrons 0.060±0.001

Neutrons 0.060±0.001

29/11/12 J.C.Anjos-RENAFAE 2012

Muons, neutrons, protons, pions, photons, positrons and electrons

29/11/12 25J.C.Anjos-RENAFAE 2012

Particle frequency density from antineutrino signal


27

Signal and cosmic background frequency

(10-200 P.E)

Table 1: Particle from antineurino signal

Table 2: Particles from cosmic background

Particles Frequency (HZ) 10-200 P.E

Positrons 0.050±0.001

Neutrons 0.050±0.001

29/11/12

Particles Frequency (HZ) 10-200 P.E

Muons 12±1

Neutrons 13±1

Protons 0.44±0.09

Pions 0.048±0.004

Photons (5.7 ± 1.1)×103

Positrons 158±48

Electrons <186 (90% C.L)


2829/11/12

Study of Gadolinium concentration

Delayed coincidence for 0.1, 0.5 and 1.0% Gd

Stopping muons and spallation neutrons for 0.1, 0.5 and 1.0% Gd


29

Study of shieldingTable 1: Cosmic neutron events

Table 2: Cosmic muons events: 10,000 generated

Shielding Neutrons simulated

Polyethylene 10.000

Water 10.000

29/11/12

Neutrons detected

Neutrons with signal delayed

299 153

282 98

Shielding Muons signal delayed

Polyethylene 56

Water 59

Spallation neutrons

Muons with multi-neutrons

28 5

17 1

Shielding Fake signals

Polyethylene 8

Water 6

Frequency (Hz)

1.3±0.5

1.0±0.4

Table 3: Muons events


29/11/12 30

Data acquisition simulation

Simulated data for one day of data taking and data reduction by each selection criteria

Generated events per day:

Muons ~ 30,000,000Cosmic neutrons ~ 340,000 Positrons from inv. Beta decay ~ 5,250Neutrons from inv. Beta decay ~ 5,250

EXPECTED RATES AT THE DETECTOR

Neutrino interactions: ~ 5,250/day ( ~ 0.06 Hz)Muon rate at target: ~ 350 HzCosmic ray induced neutron rate: ~ 70 Hz (no shielding)Cosmic neutron background: ~ 4 Hz (30cm polyethylene)

background rate must be reduced by factor ~104


29/11/12 31

Data acquisition simulation

• Clique para editar os estilos do texto mestre– Segundo nível– Terceiro nível

• Quarto nível– Quinto nível

Fit functions: Background: linear fit in time interval 150 – 300 µs

Signal: exponential (0 - 100 µs ) + linear (background)


29/11/12 32

DETECTOR STATUS


29/11/12 33

DETECTOR STATUS

Arrival of water shielding vessels at CBPF

July 2012


DETECTOR STATUS

29/11/12 34

Checking detector vessels

Starting tests at CBPF


DETECTOR STATUS

29/11/12 35

Mounting Active shielding

Covering internal walls with Tyvekand installing PMTs


ANGRA Notes

29/11/12 J.C.Anjos-RENAFAE 2012 36

Teses Defendidas

• Thamys Abrahão (CBPF) – Dez. 2012• Marcio Nunes (CBPF) – Dez. 2011• Aridio Shiappacassa (M.Sc. - CBPF) – Nov.

2011• Rafael G. Gama (CBPF) – Nov. 2011• Fernando M. B. de Sousa (CBPF) – Set.2012


Talks em Conferências

• ANDES Workshop (Valparaíso – Chile)– J. C. dos Anjos

• ENFPC 2012 (Passa Quatro – MG)– J.C. dos Anjos

• Antineutrino Applied Physics 2012 (Honolulu – EUA)– J. C. dos Anjos


Publicações


Status of the Neutrinos ANGRA project- New 40’ High Cube container: deployed in Angra

- Geant4 simulation of detector response to signal and background events: working

- Neutrino signal extraction – simulated

- New detector design: active water shield

- Water shielding and target vessels: built

- Front-end electronics: been tested

- Electronics for DAQ: ready

- Data acquisition software: ready

- Detector test at CBPF: July 2012

- Deployment in Angra: begining 2013

29/11/12 42

New Detector Technologies

ANGRA PROJECT


43

New proposal: Neutrino coherent scattering

detection at Angra


4429/11/12 44

Coherent neutrino-nucleous interaction

is a fundamental interaction predicted by

the standard model whose X-section, for Eν < 50 MeV,

is expressed by

N2 σ tot Very High

It has never been observed !!

H. da Motta 2

Coherent neutrino-nucleous interaction

is a fundamental interaction predicted by the standard model whose X-section,

for Eν < 50 MeV, is expressed by

J . C. AnjosJ . C. Anjos

XXXII - ENFPC XXXII - ENFPCFoz do Iguaçu, 07/06/2011Foz do Iguaçu, 07/06/2011

( )[ ] 22222

s i n414

NθZπEG

=σ WνF

t o t −−

N+νN+ν →

σtot very highN2

It has never been observed !!

1

Complete nuclear reactor antineutrino spectrum andthe expected events rate in Ge and Si detectors

CCD group

Abstract— This manuscritp details the antineutrino flux pro-duced by a nuclear reactor, and theexpected events in Germa-nium and Silicon detectors. It analyzes the contribution of thefour mayor isotopes(235U 238U 239Pu241Pu),andthecontributionof the 238U neutron captureprocess. Theevents rateand recoilenergy spectrum are calculated and compared to the resultsproposed by H. T. Wongref. [1].

I. INTRODUCTION

Neutrino-nucleus neutral current interaction has never beenobserved. In this process, a neutrino of any flavor scattersoff a nucleus transfering some momentum. For low energyneutrinos(Ev < 50MeV) the nuleus cross section becomesrelatively high compared to other neutrino interactions in thatenergy range. The standard model cross section for this processis given by:

dσdE r ec

=GF

2

8π[Z(4sin2θw −1)+N ]2M (2−

E r ecM

Ev2 )|f (q)|2

whete M, N and Z are the mass, neutron number and atomicnumber of the nucleus, respectively, Ev is the neutrino energyand E r ec is the mesurable recoil energy of the nucleus, f (q)is the nucleus form factor at momentum transfer q. This formfactor can be used in good aproximation as |f (q)| ∼ 1 (thecorrections are a few percent only). This formula is applicableat Ev <50 MeV where the momentum transfer (Q2) is smallsuch that Q2R2 < 1, where R is the nuclear size. At lowmomentum transfer, the nucleon wave function amplitudes arein phase and add coherently, so the cross section is enhancedby ∼ N 2.In spite of its large cross section, coherent elastic neutrinonucleus scattering has been difficult to observe due to the verysmall resulting nuclear recoil energies: the maximum recoilenergy is ∼ 2E 2

v/M , which is in the sub-Mev range.However, new ultra-low threshold detectors such as new Geand Silicon detectors (CCDs) have appeared in recent years.One common characteristic of very low threshold detectorsis their relatively small size compared to typical neutrinodetectors and therefore their small detection mass. This pushesthe use of higher intensity neutrino source so nuclear reactorseems to be a suitable solution for coherent neutrino-nucleuselastic scattering experiments.The total cross section for a monoenergetic neutrino source atenergy Ev is given by

σT ot =GF

2

4π[Z(4sin2θw − 1) + N ]2

∼ 4.22× 10−45N 2(Ev

1M eV)2cm2

0 1 2 3 4 5 6 7 8 9 10 11 1210

−46

10−45

10−44

10−43

10−42

10−41

10−40

10−39

tota

l cro

ss s

ectio

n [c

m2 ]

neutrino energy, Ev [MeV]

74Ge28Si

Fig. 1. Total cross section for 74Ge and 28Si in cm2

and is plotted for 74Ge (N=42) and 28 Si(N=14) for the reactorantineutrino energy range in fig. 1.

II. NUCLEAR REACTOR ANTINEUTRINO FLUX

Nuclear reactors emit large numbers of antineutrinos, about0.3×1020 v̄e/seg per GW of thermal power, broadly distributedover energies up to 12 MeV with a peak at 0.5-1 MeV. Theneutrinos come out isotropicaly so the expected flux at adistance L is related to the core yeild by the factor 1/ (4πL 2).The modeling of the v̄e spectrum above 3 MeV is consistentwith measurements at the < 5% level, while the low energyportion is subjected to much bigger unscertainties [2]. AboutN v̄e ∼ 7.3 v̄e are produced per reactor fission at steady stateoperation [3]. Quantity N v̄e receives contribution from manysources, but two of them have the mayor contribution:

N v̄e =F N +U N

here F N ∼ 6.1 v̄e/fission represents summed contributionfrom beta decays of fission fragments of four fissile isotopes235U 238U 239Pu 241Pu, and U N ∼1.2 v̄e/fission comes fromneutron capture by the 238U.

A. Antineutrino flux by fissile isotopes

The v̄e’s emmited in power reactors are predominantlyproduced through β-decays of the fission products, followingthe fission of the four dominant fissile isotopes: 235U 238U


COherent Neutrino-Nucleous Interaction Experiment ( CONNIE)

The use of CCD detectors (as in the DAMIC experiment) and the facilities of the Angra-neutrino project allows an opportunity to search for coherent neutrino -

nucleous scattering.

The CONNIE collaboration was initiated in 2011and brings together researcher from several institutions

H. da MottaG. AlvesJ. Anjos

M. Makler

E. Kemp C. Bonifazi

CBPF UNICAMP UFRJ

BRAZIL

J. Molina

UNA

PARAGUAY

J. EstradaH. Cease

G. Cancelo

FERMILAB

USA

We have the support of the Angra-Neutrino that allows to use the project infrastructure and the laboratory in Angra. CBPF provides

local support in Rio

27


46

CCD detectors present low electronic noise and can register nuclear recoil!

Hard to observe process

Detector should:1) be able to distinguish nuclear recoil2)present extremely low electronic noise

CCD (Charged Coupled Device)are silicon detectors that convert photons in electrons generating a current that can be quantified by an ADC


47

DAMIC CCD:- CCD are readout serially(2 output for 8 million pixels)- Very low noise level ~7.2 eV- 1 g per CCD- 18 cm2- 250 µm thick

29/11/12 47

CCD detectors have been used in dark energy and dark matter experiments like DES (Dark Energy Survey) and DAMIC (Dark Matter in CCD).

CCD detectors are potential candidatesfor experiments aimed at observing coherent neutrino-nucleous interactions.


48

MUONS ELECTRONSDIFFUSION LIMITED HITS

Nuclear recoils produce diffusion limited hits

How radiation shows in CCDs


49

Lab-A (Fermilab)

MINOS cave (100 m underground)

MINOS + lead shield


CONNIE FACTS

Number of CCD detectors: 10

Total mass: 10 g

Reactor thermal power: 4 GW

Detector distance from reactor core: 30 m

Anti-neutrino flux at the detector: ~7 x 1012 cm-2 s -1

Event rate : ~1 event every 4 days

Shielding and noise reduction are the critical factors.

Development of noise reduction techniques in the core of the project.


CCD – Angra detector

Box with 2 CCD for theCONNIE experiment

29/11/12 51

Vessel design with shield


52

Final remarks• Most of the CONNIE detector ready at FERMILAB.

• R&D needed to reduce noise. Two possible techniques under consideration to be used in the project ( G. Cancelo):

– Digital signal processing techniques for noise reduction– New CCD architecture (Skipper CCD)

• Angra-CCD neutrino detector will first be assemble at CBPF, tested and only then reassembled in Angra.

• CBPF-Angra link (for remote data acquisition) working.

• Ge detector + associated equipment and lead shield available at CBPF for all background studies needed.

• Good opportunity to develop new detector technology and advance CCD detectors technology.


29/11/12 53

Developing Know How for Future Experiments

ANGRA PROJECT


NEUTRINO OSCILLATIONS:Experiment Double CHOOZ


Neutrino Mixing MatrixExperimental situation by 2010:

• The parameters 23 and m223 determined using atmospheric neutrino data from Super-Kamiokande, K2K and Minos. (10% level)

• Data from SNO, KamLAND and Super-Kamiokande used to determine 12 and m212 with 10 – 20% precision.

• Only a limit for 13 by the reactor experiment CHOOZ (2003).

sin 2 (2 13 ) < 0.2

Atmospheric SolarReactor and LBL


1 0 00 cosθ

23sinθ

23

0 −sinθ23

cosθ23

cosθ13

0 e−iδ sinθ13

0 1 0

−eiδ sinθ13

0 cosθ13

cosθ12

sinθ12

0

−sinθ12

cosθ12

0

0 0 1

Neutrino Oscillations: open questions 2010

– Size of θ13– CP violaton effects – Mass hierarchy– Absolute mass scale

arxiv:0812.3161


Muon Electronics for the Central Detector:

João C. Anjos, Ademarlaudo F. Barbosa, Ernesto Kemp*, Herman P. Lima Jr., Iuri Pepe, Pietro Chimenti

Centro Brasileiro de Pesquisas Físicas- CBPF•Universidade Estadual de Campinas – UNICAMP

•Universidade Federal do ABC

Double Chooz Collaboration MeetingMadrid 7-10, March 2007

The Brazilian contribution:

Brazilian MuonE Team• João dos Anjos (physics/coordinator) - CBPF• Ernesto Kemp (physics) - UNICAMP• Laudo Barbosa (physics) - CBPF• Herman Lima Jr (electronics) – CBPF• Iuri Pepe (hardware-CIEMAT) – CBPF/UFBA• Pietro Chimenti (simulation software) – UFABC• Gustavo Valdiviesso (simulation software) – CBPF/UNIFAL

• TOTAL = 7 Researchers

• Students & Post-docs• Luis Fernando Gomez Gonzalez (readout software/data analysis) – UNICAMP /

APC-IN2P3 (FR)• Rafael Gama (electronic firmware and tests) – CBPF • Anderson Schilitz (data analysis) – CBPF • TOTAL = 2 PhD + 1 Post-doc

Muon electronics

- conceptual diagram

Front-end electronics

VME bus

PMT

ADC125 MHz

trigger logic

control and status registers

data builder

TDC81 ps

28 bitsstop

start*

time encoding

FPGAs

* trigger pulse from previous event

leading-edgediscriminator

control dataaddr

signal conditioning

10 bits

FIFO

DC level-1trigger

29/11/12 68

VME 6U Board waveform digitizer+ time stamp

•30 units produced and tested.

• Data acquisition with several

modules being tested

Eletronics Design - (present status 2012)


DC Internal Note:

Study of the water shield efficiency and top steel shield optimization, considering surrounding rock gamma background

G. ValdiviessoCentro Brasileiro de Pesquisas Físicas –

CBPF/UNIFAL

Neutrino Oscillations: open questions 2012

– Size of θ13– CP violaton effects – Mass hierarchy– Absolute mass scale

arxiv:0812.3161


Talks and internal notes

• The Dark Side of Universe 2012– L.F. Gonzalez

• ENFPC 2012– L.F. Gonzalez

• DC Internal Meeting 2012 (Sendai-JP)– E. Kemp (DOC-DB#3681)

• DC Internal Notes– E. Kemp, J. Felde, B. Svoboda (DOC-DB#4327)



Papers Published in 2012


Papers Published in 2012accepted in PRD


Papers Published in 2012submitted to PRD

THANK YOU


física de neutrinos de reatores - cbpfrenafae/workshops/2012/dia-1/report-dchooz_nov20… · •...

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