A Trial of Neutrino Detection from Joyo Fast Research · PDF file · 2007-11-14A...

07.11.14 suekane JAEA-IAEA 1

A Trial of Neutrino Detection from Joyo Fast Research Reactor

F.SuekaneResearch Center for Neutrino Science

Tohoku [email protected]

JAEA-IAEA Workshop on Advanced Safeguards Technology for the Future Nuclear Fuel Cycle

13-16 November 2007, Tokai-mura, Ibaraki, Japan


Collaborating Institutes and Gratitude

Tohoku Univ., Kobe Univ., Tokyo Inst. of Tech., KEK, Niigata Univ., Hiroshima Inst. of Tech.Tokyo Metropolitan Univ., Miyagi Univ. of EducationTohoku Gakuin Univ., and JAEA O-arai Reseach and Development Center.

This work has been supported by grants in aid for the scientific research,

by Japanese Ministry of Education, Culture, Sports, Science and Technology.


What is neutrino(ν)?

!"

#$%&

'$$()&

*+

,-./"

01

23

2!1020456

2!1038456

6!10554

6.6!101045s/cm2

2!1016456

2!1024456

789:;<=>?@ABCDBE

the sun

Super Nova

Nuclear Reactor

Cosmic-ray hitting Atmosphere

the earth

ν is an elementary particle which is produced in nuclear reactions.ν is the 2nd most abundant particle in the universe (next to the photon). We are living in ν sea.


Nuclear Reactor Produces a huge number of ν

~6ν's are produced per fission

~ 6 !1020" e/ s / reactor

n U235

U236*

n n

Zr94140

Cs

I140

Te140

Xe140

Rb94

Sr94

Y94

e-

e-

e-

e-

e-

e-

νe

νe

νe

νe

νe

νe

Reactor ν's are produced in β-decays of fission products.

An example of β-decay chain

Chooz data

ν energy spectrum

6% of fission energy is carried away by neutrinos.


ν for SafeguardsNuclear reactor produces a huge huge # of (~1021/s) ν's <= ν carries direct information of nuclear fuel.

The # of produced ν is proportional to the thermal power. <= ν may be used as a power monitor.

The energy spectrum and # of ν depends on fuel component. <= ν may be used as real time Pu monitor.

ν is impossible to stop. <= ν can not be hidden.

Nuclear explosion also produces a huge huge # of ν's instantaneously. <= ν may be used as nuclear testing monitor.


ν for SafeguardsNuclear reactor produces a huge huge # of (~1021/s) ν's <= ν carries direct information of nuclear fuel.

The # of produced ν is proportional to the thermal power. <= ν may be used as a power monitor.

The energy spectrum and # of ν depends on fuel component. <= ν may be used as real time Pu monitor.

ν is impossible to stop. <= ν can not be hidden.

Nuclear explosion also produces a huge huge # of ν's instantaneously. <= ν may be used as nuclear testing monitor.

However, it is extremely difficult to detect ν

and such application has not been realized yet.

ν detection technique has progressed much recently in the field of elementary particle physics.

<= Now it may be the time to seriously think about its possibility.


How to measure Pu/U ratio by ν

!

Pth = q nU + nPu( )

N" = anU +bnPu

# $ %

!

nPu

nU=1" ar

br "1; r =

Pth

qN#

0

5

10

15

20

0 1 2 3 4 5 6 7 8 9 10

E!(MeV)

#ev

ent/

MeV

/GW

th/1

030 p

roto

n/d

ay

@ 1

km

235U

239Pu

a

b

nU, nPu: Fission rate of U and Puq: Energy release per fission (~200MeV)Pth: Thermal powerNν: # of νa, b: # of ν generation per U, Pu fission (a/b~1.5)

(simplified discussion)


Activity of ν physicists.

1st: Feb. 5-7, 2004 @Univ. of Hawaii, USA2nd: Dec.14-16, 2005 @Univ. of Hawaii, USA3rd: Sept.24-26, 2006 @ Laurence Livermore National Lab., USA

And 4th: Dec. 23-24, 2007 @ Saclay, France

= Applied Antineutrino Physics Workshops =

Next Slide


ν detection from San-Onofre Nuclear Reactor

San-OnofreNuclear Reactor

Burn-up effect=> Change of U/Pu ratio

FromN.S.Bowden et al. N.I.Meth.A572:985-998,2007& Talk slide from AAP2006


!

P

L2"

observed ν rate

KamLAND experiment (JAPAN); ν detection from reactors180km away

ν target=1kton of liquid scintillator


How ν is detected

p

e+

nν

scintillation light

positron

!"

#$$$%&

'()*

Reaction probability=10−18%with 1ton of scintillator.

neutirno

Photomultiplier(photo sensor)

Chemical component of scintillator ~ CxHyOz

!

" + p# e+

+ n


KASKA Experimentν detectorν detectorν detector

Kashiwazaki-Kariwa Nuclear Power Station

ν detector

ΣP=24.3GWth(world's highest Power)

R&D 2003-2006

Purpose is to detect the last neutrino oscillationand measure mixing angle θ13


KASKA Prototype:for ν Detector R&D

in Tohoku Univ.


Prototype@Joyo(JAEA) research reactor

!"#$%&'

()*+, ()-.,

/0123

4567

89:;<=>?@A

BCDE*+'

F9:;<=>?@ABGHIJ1

!"#KL

!"#MNKL

!"#&'

#O

PQR4567

STU>?VW-'

>2JXYZU[U\

Fast Reactor (Pu rich)Pth=140MWFrequent ON/OFFL~25m~150 νp−>e+n reaction/day

KASKA Prototype

25m


Why Joyo?

* Practical Reason:Research Reactor is easier to access.

* Scientific Interest: ν from fast reactor has not been measured. * Technological Interest ν spectum from U and Pu can be measured separately by combining with the data from Light Water Reactor

However, the thermal power is small (1/20 of San-Onofre) and it is

challenging to detect ν at Joyo.

U

Pu#

of ν

# of

νU

LWR

Fast Reactor

Pu

Measured

Not measured

(Does not scale)


Prototype@Joyo research reactor

Not to scale

0.05% Gd Liquid Scintillator (900L)

Lead Shields

Cosmic-ray anti-counters

Light shield

Paraffin Blocks

N2

* 0.05% Gd LS(10%BC521+15%PC+75%isoParaffin oil)* Lead shield,* Cosmic-ray anti counter* Paraffin Blocks* n/γ pulse shape discrimination(PSD)


Acrylic sphere & Liquid Scintillator

Cosmic veto counter

Paraffin blocks

Electronics

In Joyo Building


Neutrino Detection

! e + p" e+

+ n

Then

e+ + e! " 2# 2 $ 0.511MeV( )

n +Gd! Gd' +" ' s E"# ~ 8MeV( )!

"#

#$

#%

&'()*++,#-.

&'()*++,#-.

/

01

&

&&

&

E!" ~ 8MeV

2(34

!567!894:;/<=

>#=<?#194:;/<=

!"#$

%&'(

)*!"#$

+

,-./0123456#4+7

=> use Gd


Energy Correlation of Prompt and Delayed Signals

1

10

104

105

1

10

102

103

104

Background (/day/0.4MeV/0.4MeV) AmBe + Background (/day/0.4MeV/0.4MeV)105

1

10

102

103

104

105

Del

ayed

Ede

p(M

eV)

0 2 4 6 8 10 12 14 16 18 20Prompt Edep(MeV)

0 2 4 6 8 10 12 14 16 18 20Prompt Edep(MeV)

20

18

16

14

12

10 8 6

4

2

0

20

18

16

14

12

10

8

6

4

2

0

Del

ayed

Ede

p(M

eV)

simulated ν signal(Am/Be source)

Back grounds: * γ-rays from U, Th, K, Rn * cosmic-rays


Energy Spectrum in ν windowOn:20days, Off:20days

13 ± 4

163 ± 3

150 ± 3

Total events

135 ± 315 ± 0.01Reactor OFF

7 ± 46 ± 0.01ON - OFF

142 ± 321 ± 0.01Reactor ON

Correlated eventsAccidental BG

- Reactor ON- Reactor Off- Accidental (Reactor ON)- Accidental (Reactor OFF)

Rate

(/day

/Mev

)

E(Mev)

Preliminary


ν candidate（Data vs MC）

・ Dataー　MCPreliminary

Expected

Nν=NON-NOFF

So far no significant positive result yet.


Possible Future improvements

More Statistics,Pusle Shape neutron-e+ separation,Better Fiducial cuts,Use Timing inforamtion, :


Summary

*In this talk, our effort to detect ν from Joyo research reactor was presented. * There are similar activities in worldwide and this kind of ν detector may be able to be used as a monitor of nuclear reactor operation in the future.

A Trial of Neutrino Detection from Joyo Fast Research · PDF file · 2007-11-14A...

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