Ba Tagging activities in EXO

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6/11/11 TIPP 2011 1 Ba Tagging activities in EXO Karl Twelker Stanford University Enriched Xenon Observatory TIPP Conference June 11, 2011

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Ba Tagging activities in EXO. Karl Twelker Stanford University Enriched Xenon Observatory TIPP Conference June 11, 2011. EXO neutrino mass sensitivity. Assumptions: 80% enrichment in 136 Intrinsic low background + Ba tagging eliminate all radioactive background - PowerPoint PPT Presentation

Transcript of Ba Tagging activities in EXO

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Ba Tagging activities in EXO

Karl TwelkerStanford University

Enriched Xenon ObservatoryTIPP Conference

June 11, 2011

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EXO neutrino mass sensitivityAssumptions: 1) 80% enrichment in 1362) Intrinsic low background + Ba tagging eliminate all radioactive background3) Energy res only used to separate the 0ν from 2ν modes: Select 0ν events in a ±2σ interval centered around the 2.481MeV endpoint4) Use for 2νββ T1/2>1·1022yr (Bernabei et al. measurement)

* s(E)/E = 1.4% obtained in EXO R&D, Conti et al Phys Rev B 68 (2003) 054201† s(E)/E = 1.0% considered as an aggressive but realistic guess with large light collection area‡ F.Simkovic et al., Phys. Rev. C79, 055501 (2009)# Menendez et al., Nucl. Phys. A818, 139 (2009)

Case Mass(ton)

Eff.(%)

Run Time(yr)

σE/E @ 2.5MeV

(%)

2νββBackground

(events)

T1/20ν

(yr, 90%CL)Majorana mass

(meV)QRPA‡ NSM#

Conservative 1 70 5 1.6* 0.5 (use 1) 2*1027 19 24

Aggressive 10 70 10 1† 0.7 (use 1) 4.1*1028 4.3 5.3

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TPC locates decay

• Either a gas or liquid TPC will allow precise location of the decay and the daughter nucleus.

Cathode

Y wires

X wiresLight collection

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Background control

Backgrounds must be controlled at an extreme level.

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We’re going to tag the daughter nucleus.

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G.Gratta, EXO R&D 5

Lots of tagging operations

NSF S4 review, Arlington Jul 14, 2010

Sub task Where Status (Jul 2010)

1 Ion trap with Laser tagging Stanford Done

2 Cold probe TUM Being assembled

3 RIS probe Stanford Sensitivity >10-3, installing new setup

4 Hot probe SLAC/ Stanford Work in progress

5 Low E Ba+,Ba++ implant in SXe

CSU Pulsed Ba+, Ba++ beam almost ready

6 Direct detect. in LXe CSU Conflicting evidence for Ba+ vs. BaO

7 Detection on fiber tip CSU Sensitivity ~104 Ba atoms with window. 1 dye molecule with fiber

8 LXe dipper Stanford Hardware in hand9 Cs-137 source UMD Working in vacuum

10 Gd-BaF2source Stanford Working, in use

11 Triggered source in vac. Stanford Under development

12GXe to vac pumping demo Stanford All major components in hand. Assembly

started.

13 Nozzles Carleton/Stanford

Nozzle test chamber being assembled

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G.Gratta, EXO R&D 6

Lots of tagging operations

NSF S4 review, Arlington Jul 14, 2010

Sub task Where Status

1 Ion trap with Laser tagging Stanford Done

2 Cold probe TUM Being assembled

3 RIS probe Stanford Sensitivity >10-3, installing new setup

4 Hot probe SLAC/ Stanford Under development

5 Low E Ba+,Ba++ implant in SXe

CSU Pulsed Ba+, Ba++ beam almost ready

6 Direct detect. in LXe CSU Conflicting evidence for Ba+ vs. BaO

7 Detection on fiber tip CSU Sensitivity ~104 Ba atoms with window. 1 dye molecule with fiber

8 LXe dipper Stanford Hardware in hand9 Cs-137 source UMD Working in vacuum

10 Gd-BaF2source Stanford Working, in use

11 Triggered source in vac. Stanford Under development

12GXe to vac pumping demo Stanford All major components in hand. Assembly

started.

13 Nozzles Carleton/Stanford

Nozzle test chamber being assembled

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Gas tagging test system

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To test Ba+ extraction from high pressure Xe

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The same idea used in exotic nuclei production

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The system before assembly

High capacity Xe cryopump

Low pressurechamber(“Chamber B”)

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Gas tagging transport test

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Possible barium identification

Single Ba+ ions can be detected from a photon rate of 107/s (Neuhauser, Hohenstatt, Toshek, Dehmelt 1980)6/11/11

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Vcos(Ωt) + U

UDC

pot

entia

l [V]

0 Volts

-5 Volts

BaBuffer gas

CCD

Spectroscopy lasers

Scope

Our RF Paul Trap

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Stanford Linear Paul Trap

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Single ion detection

M.Green et al. Phys Rev A 76 (2007) 023404B.Flatt et al. NIM A 578 (2007) 409

~9σ discrimination in 25s integration

Trap can detect single ions in high pressure gas (He, Ar)

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Initial tests on a window

The detection limit is as low as 104 ions deposited, but many fewer are in the laser spot.

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Detecting Ba while still in LXeIons could be trapped in solid xenon frozen on the end of an optical fiber.

The fiber could be used to both illuminate the ion and capture fluorescence from the ion.

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EXO has already achieved single dye molecule detection with fiber

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Resonance Ionization Spectroscopy as a release technique

6s2 1S0

553.5nm

389.7nm

Ba+ 6s

Ba+ 5d

6s6p 1P1

5d8d 1P1

Reso

nant

ioni

zatio

n sc

hem

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Schematic of the test system

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Optical Spectroscopy Identification:Detuning the lasers

Autoionization state

Ionization to continuum

553.5 nm Laser Detuning 389.7 nm Laser Detuning

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RIS from gas phase

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Mass Spectroscopy Identification: time of flight

A typical channeltron pre-amp readout. Ba atoms are desorbed at t=0.

Ba+ from desorption laser

Desorbed and resonantly ionizedBa+

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Desorption LaserFires

RIS LasersFire

-2kV

Ground

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Single Ion Source

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Surfacebarrierdetector

Electroplated148Gdsource~10 layers

EvaporatedBaF2 15nm

Ba+

α tag

Use recoils from a very thin α emitter to dislodge Ba atoms from a carefully designed layer of BaF2

A fraction of the Ba emitted is Ba+

H+

C+

Na+

Si+

C2H5O+

C3H8O+

Ba2+

Ba+

BaF+

Rev. Sci. Inst. 81, 113301 (2010)

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Efficiency >10-3 (deposit 105, get >100 out)

Gaining efficiency

Ion Source

CEM

SiliconSubstrate

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Ions deposit

RIS

test

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Something to build on…

• Gas tagging R&D is progressing, transport test ready soon.

• Barium ion spectroscopy in solid xenon is approaching single-ion level.

• Resonance Ionization Spectroscopy efficiencies are > 10-3 and growing, the new system will allow for single ion operation.

• More tagging operations are in progress.

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D.Auty, M.Hughes, R.MacLellan, A.Piepke, K.Pushkin, M.Volk, Dept of Physics & Astronomy, U. of Alabama, Tuscaloosa ALM.Auger, D.Franco, G.Giroux, R.Gornea, M.Weber, J-L.Vuilleumier,High Energy Physics Lab,Bern,SwitzerlandP.Vogel Physics Dept Caltech, Pasadena CAA.Coppens, M.Dunford, K.Graham, P.Gravelle, C.Hägemann, C.Hargrove,F.Leonard, K.McFarlane, C.Oullet, E.Rollin, D.Sinclair, V.Strickland,Carleton University, Ottawa, CanadaC.Benitez-Medina, S.Cook, W.Fairbank Jr., K.Hall, N.Kaufhold, B.Mong,T.Walton, Colorado State U., Fort Collins COL.Kaufman, Indiana UniversityM.Moe, Physics Dept UC Irvine, Irvine CAD.Akimov, I.Alexandrov, V.Belov, A.Burenkov, M.Danilov, A.Dolgolenko, A.Karelin, A.Kovalenko, A.Kuchenkov, V.Stekhanov, O.Zeldovich, ITEP Moscow, RussiaE.Beauchamp, D.Chauhan, B.Cleveland, J.Farine, D.Hallman, J.Johnson, U.Wichoski, M.Wilson, Laurentian U., CanadaC.Davis, A.Dobi, C.Hall, S. Slutsky, Y-R. Yen, U. of Maryland, College Park MDJ. Cook, T.Daniels, K.Kumar, A.Pocar, K.Schmoll, C.Sterpka, D.Wright P. Morgan, UMass, AmherstD.Leonard, University of Seoul, Republic of KoreaM.Breidenbach, R.Conley, W.Craddock, S.Herrin, J.Hodgson, J.Ku, D.Mackay, A.Odian, C.Prescott, P.Rowson, K.Skarpaas, M.Swift, J.Wodin, L.Yang, S.Zalog, N. Ackermann SLAC, Menlo Park CAP.Barbeau, L.Bartoszek, J.Davis, R.DeVoe, M.Dolinski, G.Gratta, F.LePort, M.Montero Diez, A.Müller, R.Neilson, A.Rivas, A. Saburov, K.O’Sullivan, D.Tosi, K.Twelker, Physics Dept Stanford U., Stanford CAW.Feldmeier, P.Fierlinger, M.Marino, TUM, Garching, Germany

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Backup Slides

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Background and neutrino mass sensitivity

NtTm /1/1 02/1

mν ∝ 1/ T1/ 20νββ ∝ 1/ Nt( )1/ 4

Without background:

With background:

Backgrounds must be controlled at an extreme level.

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Can be Identified with optical spectroscopy

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Hot ionizer design

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Hot ionizer scheme

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The RIS test apparatus

Chan

neltr

onSi Substrate

Single Ion Source

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