future sk program for n e physics n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Future SK Program for n e Physics PowerPoint Presentation
Download Presentation
Future SK Program for n e Physics

Loading in 2 Seconds...

play fullscreen
1 / 43

Future SK Program for n e Physics - PowerPoint PPT Presentation


  • 99 Views
  • Uploaded on

Future SK Program for n e Physics. Atsuko Kibayashi For the Super- Kamiokande Collaboration Okayama University June 14, 2013. Motivations. Neutron Capture by Gadolinium. 100% 80% 60% 40% 20% 0%. Captures on Gd. L arge cross section of Gd for neutron capture

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Future SK Program for n e Physics' - benny


Download Now An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
future sk program for n e physics

Future SK Program for ne Physics

Atsuko Kibayashi

For the Super-Kamiokande Collaboration

Okayama University

June 14, 2013

RENO50

motivations
Motivations

RENO50

neutron capture by gadolinium
Neutron Capture by Gadolinium

100%

80%

60%

40%

20%

0%

Captures on Gd

  • Large cross section of Gd for neutron capture
    • ~49,000 barns (0.3 barns on free proton)
  • Coincident signal detection to suppress background
  • Beacom and Vagins, Phys. Rev. Lett., 93:171101, 2004]

ne

n

p

Gd

+

e

γ

8 MeV

ΔT~20μs

Vertices within 50cm

  • 0.1% Gd gives 90% neutron capture eff.
  • ~100ton of Gd2(SO4)3 in SK

0.0001% 0.001% 0.01% 0.1% 1%

RENO50

Gd in Water

slide4
Physics of neby GADZOOKS!Gadolinium Antineutrino Detector Zealously Outperforming Old Kamiokande, Super!
  • Observation of Supernova Relic Neutrino (SRN)
    • SRN has not yet been observed
  • Supernova Burst Neutrinos
    • Better direction determination by enhancement of electron scattering events
  • Reactor Neutrinos
    • Precise measurements of oscillation parameters by high statistics

RENO50

srn spectrum
SRN Spectrum

SRN flux calculations

Horiuchist al. PRD, 79, 083013 (2009)

Expected no. of SRN events

1.3-6.7 events/year/22.5kton (10-30MeV)

Expected SRN Spectrum

(ne fluxes)

  • Need:
  • Large target mass
  • Background removability

RENO50

expected srn signal and background
Expected SRN Signal and Background

Assume :

  • 90 % neutron capture efficiency,
  • 74% Gd gamma detection efficiency,
  • invisible muon B.G. is 35% of the SK-IV invisible muon B.G.

Expect:

  • 10-45 SRN events in 10-years data taking (Evis = 10-30 MeV)

RENO50

slide7

Supernova Burst Direction

ne+p

ne+p

ne+p

ne+p

w/o Neutron Tagging

n+e

n+e

n+e

n+e

SN at 10kpc

Neutrino flux and spectrum from Livermore simulation

RENO50

slide8

Supernova Burst Direction

ne+p

ne+p

ne+p

ne+p

w/ Neutron Tagging

Removing tagged events

n+e

n+e

n+e

n+e

SN at 10kpc

Neutrino flux and spectrum from Livermore simulation

RENO50

slide9

SN Direction Determination Precision

H. Ishino

Direction Determination Precision (1000MC events)

Direction Determination Precision

tag eff. = 1.0

振動なし

No Osc.

振動あり(正階層性)

Oscillated (normal hierarchy)

tag eff. = 0.8

振動あり(逆階層性)

Oscillated(inverted hierarchy)

Number of supernovae

tag eff. = 0.0

2x better precision with neutron tagging.

RENO50

questions
Questions

Gd in SK?

  • Water transparency?
  • How to purify Gd water?
  • How to introduce/remove Gd?
  • Effect on SK material?
  • Effect on solar neutrino analysis?
  • In a water Cherenkov detector?

EGADS

RENO50

egads
R&DEGADS

RENO50

slide12

Super-Kamiokande

EGADS

Evaluating Gadolinium’s Action on Detector Systems

EGADS hall

SK water purification system

To Atotsu entrance

50m

Parking place

Underground site map

RENO50

slide13

EGADS Lab. in Kamioka Mine

Transparency measuring device

Gd Removing Resin

200m3SUStank

Feb.16, 2011

15 m3plastic tank

(for dissolving Gd)

Gdpurification

(resin to remove U keeping Gd)

Gd-water filtration

RENO50

slide14

M. Vagins

Membrane filter technology

Water Monovalent Multivalent Viruses Bacteria Suspended

Ions Ions Solids

Microfiltration

1,000 – 100,000 angstroms

membrane pore size

Ultrafiltration

100 – 1,000 angstroms

membrane pore size

Nanofiltration

10 – 100 angstroms

membrane pore size

Reverse

Osmosis

5 – 15 angstroms

membrane pore size

Water Monovalent Multivalent Viruses Bacteria Suspended

Ions Ions Solids

Water Monovalent Multivalent Viruses Bacteria Suspended

Ions Ions Solids

Water Monovalent Multivalent Viruses Bacteria Suspended

Ions Ions Solids

small

large

size

Gd2(SO4)3

slide15

EGADS Selective Filtration System

M. Vagins

To Drain

UF#1 Reject Line

Ultrafilter #1

Ultrafilter #1

Chiller

200 ton EGADS

Main Tank

UV

#1

0.2 m

2nd Stage Filter

Repressurization

Pump

(>0.6 MPa, >4 ton/hr)

5 m

1st Stage

Filter

Intake

Pump

(>4 ton/hr)

Membrane

Degas

UF#2

Reject

Nanofilter #1

Nanofilter #1

0.5 ton Collection Buffer Tank

Concentrated Gd NF Reject Lines

Nanofilter #1

Nanofilter #1

Conveying

Pump

(~0.35 MPa,

>4 ton/hr)

Ultrafilter #2

Ultrafilter #2

Recycles RO Reject Lines

UV

#2

0.5 ton Buffer Tank

Repressurization

Pump

(>0.6 MPa, >3 ton/hr)

RO Permeate Lines

Nanofilter #2

Nanofilter #2

Nanofilter #2

TOC

Repressur-ization

Pump

(>0.9 MPa, >2 ton/hr)

DI

#2

Repressurization

Pump

(>0.9 MPa, >1.5 ton/hr)

DI

#1

RO #2

5 m

Filter

5 m

Filter

RO #1

RENO50

egads step 1
EGADS (Step 1)

200 m3tank

15m3tank

Gd-water filtration system

w/o PMT

  • Circulation of pure water in200 m3 tank, to evaluate basic performance of the filtration system
  • March – June, 2011
egads step 2
EGADS (Step 2)

200 m3tank

15m3tank

Gd-water filtration system

w/o PMT

  • Circulation of 0.2% Gd2(SO4)3 dissolved waterin15m3 tank through the filtration system
  • Measurement of Gd-dissolved water transparency
  • August, 2011 – December, 2012
egads step 3
EGADS (Step 3)

200 m3tank

15m3tank

Gd-water filtration system

w/o PMT

  • Circulation of 0.2% Gd2(SO4)3 dissolved waterin 200m3 tank through the filtration system.
  • Study of effects on SUS tank (accelerated studies have shown no problems)
  • December, 2012 – June, 2013
slide20

Light Remaining at 15 m in 200 ton tank

M. Vagins

SK-III and SK-IV Ultrapure Water = 74.7% - 82.1% @ 15 m

70 %

=> 85% of pure water

60 kg of Gd2(SO4)3*8H2O 52% n capture on Gd

89.4 kg of Gd2(SO4)3*8H2O 62% on Gd

149.4 kg of Gd2(SO4)3*8H2O 73% on Gd

274 kg of Gd2(SO4)3*8H2O 83% on Gd

400 kg of Gd2(SO4)3*8H2O 88% on Gd

30 kg of Gd2(SO4)3*8H2O 35% n capture on Gd

RENO50

egads step 4
EGADS (Step 4)

200 m3tank

15m3tank

Gd-water filtration system

  • 240 PMT mounting
  • July - August, 2013
egads last step
EGADS (last Step)

200 m3tank

15m3tank

Mini-SK

(w/ same SK material)

Gd-water filtration system

  • Circulation of pure water, then 0.2% Gd2(SO4)3 dissolved water
  • Integrated test
  • Starting September, 2013
gadzooks
forGADZOOKS!

RENO50

effect on solar neutrino analysis

M. Smy

Effect on Solar Neutrino Analysis?
  • To achieve 3.5 MeV(Kin.) solar neutrino analysis in 0.2% Gd+H2O SK, the following radioactivity levels would be needed.

< 2.8 x 10-11 g(238U)/g(Gd)

< 8.6 x 10-11 g(232Th)/g(Gd)

< 9.6 x 10-18 g(226Ra)/g(Gd)

=>Corresponds to < 0.35 mBq/kg(Gd)

RENO50

radioactivity of gd 2 so 4 3

L. Labarga

Radioactivity of Gd2(SO4)3

Radioactivity in Gd2(SO4)3batches measured in Canfranc[mBq/Kg, limits are @ 95% c.l.]

Still too high

preliminary

=> To reduce Radium, one solution is to use commercial selective resins available.

RENO50

answers
Answers

Gd in SK?

  • Water transparency?
  • How to purify Gd water?
  • How to introduce/remove Gd?
  • Effect on SK material?
  • Effect on solar neutrino analysis?
  • In a water Cherenkov detector?

85% of pure water

Method being established

Mass removal still under study,

commercial resin available

Gd2(SO4)3 proven to be safe

Radioactivity still too high (esp. Ra). Commercial resin will be tested.

Demonstration of Cherenkov detection of Gd(n, gamma) Gd

(H.Watanabe et al. Astropart. Phys., 31, 320-328 (2009)

RENO50

conclu sion
Conclusion
  • For SRN detection
    • A large target volume is needed => SK is the only one w/ that kind of volume
    • Addition of Gd unable us to detect SRN
  • For SN detection
    • Direction accuracycan be improved by tagging ne events

Gd in water Cherenkov detector R&D project (EGADS) is in progress.

Gd in SK looks more and more promising.

As soon as EGADS successfully demonstrates the feasibility for GADZOOKS!,

schedule for GADZOOKS! will be discussed among the SK collaboration.

We hope to start GADZOOKS! in a few years.

RENO50

backups
Backups

RENO50

egads members
EGADS Members
  • ICRR, University of Tokyo
    • Y. Kishimoto , M. Nakahata, H. Sekiya
  • Kavli, IPMU
    • L. Marti, M. Vagins
  • Kobe University
    • Y. Takeuchi
  • Okayama University
    • H. Ishino, A. Kibayashi, Y. Koshio, T. Mori, M. Sakuda, Y. Yamada, T. Yano,
  • University Autonoma Madrid
    • L. Labarga, P. Fernadez
  • University of California, Irvine
    • G. Carminati, J. Griskevich, B. Kropp, A. Renshaw, M. Smy, P. Weather

RENO50

slide31

Concept of the water circulation system

Gd2(SO4)3

(NF reject)

Gd2(SO4)3and

UF passed water

(UF pass)

Water with

Gd2(SO4)3from the tank

Ultrafilter

Nanofilter

Small size contaminants

(NFpass)

Reject large size contaminants

(UF reject)

RO

pure water

(RO pass)

and Gd2(SO4)3

Return to tank

RO reject

(processed in another loop)

reactor neutrino at gadzsooks
Reactor Neutrino at GADZSOOKS!

Number of events at SK per year(~3000/year)

Sensitivity of parameter measurement

(10 years)

w/o oscillation

95%CL

very preliminary

w/ oscillation

Δm2 (10-4eV)

10 years’ sensitivity

With / without oscillation

sin2(2θ)

Current solar+KamLANDerror size

MeV

slide33

M. Vagins

100%

80%

60%

40%

20%

0%

Thermal

neutron

capture

cross

section

(barns)

Gd =49700

S =0.53

H =0.33

O =0.0002

Captures on Gd

400 kg  88%

274 kg  83%

149.4 kg  73%

89.4 kg  62%

60 kg  52%

30 kg of Gd2(SO4)3 8H2Oin 200 tons 35% captureon gadolinium

Gd in

Water

0.0001% 0.001% 0.01% 0.1% 1%

RENO50

slide34

[Yano-san]

RENO50

slide35

[Yano-san]

RENO50

slide36

[Yano-san]

RENO50

slide38

M.Smy, “Low Energy Requirements for the GADZOOKS! Project”,

SK meeting, Dec.3, 2006

RENO50

Y. Takeuchi, ICRR

epoxy test paint on welded part of the sus tank
Epoxy Testpaint on welded part of the SUS tank

M20 bolts in a flange apply epoxy w/o welding.

BIO-SEAL 197

BIO-DUR 560

Epoxy paints on the base of bolt.

RENO50

epoxy test
Epoxy Test

Pressure vessel

Pressure test (0  5kg/cm2) was done on Oct.19, 2011.

No leak and no pressure drop.

Pressure cycle (0  5kg/cm2) test was done on Oct.20-27.

No leak and no pressure drop.

Long term stability test is running from Oct.28 for 3 months and no problem was found.

The test flanges are put on both sides and give pressure to the vessel.

Successful

RENO50

possibility of acrylic vessel additional layer of protection
Possibility of Acrylic Vesseladditional layer of protection

Outer detector

Inner detector

Acrylic vessel

Gd-loaded water

Basic idea: extend the frame above the PMTs and put thin acrylic plates.

RENO50

slide42

Test Cherenkov emission of Gd(n,g)Gd

GdCl3 test vessel

This apparatus deployed in the SK tank.

BGO

0.2 % GdCl3

Solution

18 cm

5 cm

BGO

Am/Be

13 cm

18 cm

BGO signal (prompt signal (large and long time pulse))

Look for Cherenkov signal (delayed signal)

α+ 9Be→12C*+n

12C*→12C+ g(4.4 MeV)

n+ p → …… →n +Gd→Gd+g (totally 8 MeV)

cherenkov signal of gd gamma rays
Cherenkov signal of Gd gamma rays

Time from prompt

Energy spectrum

0

100ms

Vertex position

92% within 2m

Measured time, vertex and energy distributions are as expected from the MC simulation.

Astropart. Phys. 31, 320-328 (2009)

arXiv:0811.0735

dR [cm]