positron probe microanalyzer (ppma) and other accelerator ...maximum slow positron yield 500 550 109...

Positron Probe Microanalyzer (PPMA) and other accelerator based slow positronand other accelerator based slow positron

facilities at AISTB. E. O’Rourke, N. Oshima, A. Kinomura, T. Ohdaira and R. Suzuki

National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, Japan

10th International Workshop on Positron and Positronium Chemistry

Smolenice Castle, Slovakia, 7th Sept 2011

PPC10 Slovakia, 7th Sept 2011

AIST Electron Accelerator Facility

300 MeV e- LINAC(1979- )

New e+ beamline

SCA

(PPMA, PALS)

Slow e+ beamline

Existing e+ facilities(PALS, PPMA, PAES)


Slow e beamline(1988- )

AIST LINAC-based Slow Positron Beam

PALSPPMAPALS

TOF-PAES

e-Ta converter

70 MeV, 100mA peak, 1 s, 100 pps

Linear Storage S ti

ppSection

W moderatorBremsstrahlung

+


slow e+

+Pair Production

AIST LINAC-based Slow Positron Beam

PALSPPMAPALS

TOF-PAES

e-70 MeV, 100mA peak,

1 s 100 pps

Linear Storage S ti

Positron / Ion combined Beamlinee

Ta converter1 s, 100 pps Section

positron

Bremsstrahlung

ion

sample

p

PPC10 Slovakia, 7th Sept 2011slow e+

W moderator Bremsstrahlung+

Pair Production

sample

RI-based PALS22Na 1 GBqCounting rate ~4,000 cpsTime resolution < 200 psTime resolution < 200 ps

Time resolution ~250 ps

3 m

10-1

100

Kapton 通常セットアップ

　　　BaF2 50x50mm 時間分解能 250ps テスト用セットアップ

　　　BaF2 40x10mm 時間分解能 155ps

3 mBest resolution：

155 ps

-3

10-2

=385psNorm

aliz

ed

counts

1.5 mCommercially available

PPC10 Slovakia, 7th Sept 2011-1 0 1 2 3 4

10-4

10-3

Time (ns)

Commercially availablefrom FUJI IMVAC Inc.

PAES

e+ Pulsing Apparatus

PAES

g pp


PPMA

6

Positron Probe Microanalyzer (PPMA)


http://www.aist.go.jp/aist_j/press_release/pr2008/pr20080828_2/pr20080828_2.html 7

Positron Probe Microanalyzer (PPMA)N. Oshima et al., Radiat. Phys. Chem. 78, 1096 (2009)

Buncher Focusing lens

PPC10 Slovakia, 7th Sept 2011 8

Focusing lens

PALS System for Positron Microbeam

PAL spectra with micro beam

10-1

100 SiO2 un-irradiatedSiO2 H

+ 50 keVKapton

d C

ount

s

10-3

10-2

Nor

mal

ized

Resolution < 200 ps

0 5 1010

Time(ns)

Resolution 200 psDiameter： <30 m

Counting rate:g1-3k cps for 30 um


Positron Probe Microanalyzer (PPMA)

R d

Objective Lens

Remoderatorx-y stage

Lens


http://www.aist.go.jp/aist_j/press_release/pr2008/pr20080828_2/pr20080828_2.html10

Brightness Enhancement SystemB i ht h t

Reemission of positrons

～ keV

ter

10mm

Brightness enhancement

Moderator

~ eV

Bea

m d

iam

et

10μm

100μm

1mm

Energy(eV)

1 10 100 1k 10k 1μm

Magnetic guide(~20m) Focusing Lens

Ni RemoderatorExtraction Coil

accelerationN. Oshima, J. Appl. Phys. 103 094916 (2008)

RF


Pulsing system

Beam Diameter / Time Width of Bunch

Beam

0.3 ns 0.1 nsPulse Width: 5 -10 ns

2 3 kcpsBeam 2-3 kcpsfor

PALS

Beam Size: ~10 mm (FWHM) ~1 mm (FWHM)

at remoderator~25m(FWHM)

at samplein solenoid at remoderator at sample

SiO2

Ta2


J. Appl. Phys. 103, 094916 (2008)

3-D Mapping of Defects

unimplanteda-SiO2

Resolution ~200 psDiameter： <30 m

Counting rate:

Appl. Phys. Lett. 94,

a-SiO2

implanted

Counting rate:1-3k cps for 30 m

194104（2009）

Defects created by Ar+

Mean impl. Depth (Energy）

p

created by Ar and H+ 200 nm

（4.7 keV） Focused e+ beam

H+ ion beam Ar+ ion beam 350 nm （6.4 keV） Scan

(50 keV、1016cm-2) (150 keV 、1015cm-2)

30 mesh

500 nm （7.8 keV）

Sample

１pixel ： 50 μm x 50 μm

Defects created by H+

Rotate 45o


（ ~1 s/pixel）total：３５００pixels

long short lifetime a-SiO2 Depth 600 nm

Depth 200 nm

PPMA – Ductile Fractured Iron Samplenominal strainnominal strain = 0 % 0.5 % 0.5 % 2.9 % 14.7 %

uck

V4 V5V7-V10e

chu

V4-V51 mm

gaug

ech

uck

it lif ti

(PPMA parameters)Beam energy : 25 keV

average positron lifetimeBeam diameter ： 50 mScanning step ： 50 m2 (gauge area)

100 m2 (chuck area)

PPC10 Slovakia, 7th Sept 2011 14

130 ps-ray counts : 5000 / pixelMeasurement points : 10,000 / image

180 ps

Extraction of Slow Positrons to Air

50

60

SiO2(100nm)/Siin vacuum

50

60

SiO2(100nm)/Siin vacuum

20

30

40 in vacuum in air with SiN(30nm)

I 3 (%

)

20

30

40 in vacuum in air with SiN(30nm)

I 3 (%

)

0 5 10 15 20 250

10

positron beam energy (keV)0 5 10 15 20 250

10

positron beam energy (keV)positron beam energy (keV)positron beam energy (keV)


N. Oshima et al., Appl. Phys. Express 4, 066701 (2011)

Nanotechnology shared infrastructure

Nano Characterization

Nano Processing Facility (NPF)

Manufacturing CenterResearch SupportTechnical TrainingTechnical Training

HR-NMR

Electron Microscope


MEMS FoundaryElectron Microscope


300 MeV e- LINAC(1979- )

New e+ beamline

SCA

(PPMA, PALS)

Slow e+ beamline




New Positron Beamline

Goal:

To increase the speed and efficiency and volume of our yPALS and PPMA measurements

Current Situation:PPMA

Under construction. Should be ready for tests with electrons

PALS

ready for tests with electrons soon and first positrons within this fiscal year (March 2012)



240

Positron Converter & Moderator

PPMAPALS

3

Linear Storage Section

1240

Con

cret

e Sh

ield

43255540 2166

Accelerator Concrete WallPositron Experimental Room


Roomp


Positron Converter &

PPMAφ10 Linear Storage Section Converter &

Moderator

Concrete Wall

RF Buncher(125MHz)

Section

Concrete WallRe-

moderatror

RF Buncher (125 MH )


(125 MHz)


300 MeV e- LINAC(1979- )

New e+ beamline

SCA

(PPMA, PALS)

Slow e+ beamline




Superconducting Accelerator (SCA)CW or high duty operation

24 h operation

Energy gain 7.5 MeV

High power (> 10 kW) 40K/80K refrigeratorRecondensor

High power ( 10 kW)

80K heat shield

40K heat shield

He port

RF Coupler

Nb cavity

2905

y

200

HOM coupler 12


3240

Current Situation at AIST

Current LINAC

SCA Module 1 (Present Position)

Positron


10 mPositronExperimentalRoom

10 m


Initial Set-up Plan

Current LINAC

Positron Convertord M d

New Beamline


Positron

and Moderator SCA Module 1 (Present Position)

Positron Beamline

10 mPositronExperimentalRoom

10 m


Monte Carlo Simulation

Step 1: Calculate energy and angular emission distributions of fast e+

Step 2: Calculate the depth distribution


profile of e+ absorbed in W

Slow Positron Production

100100

%4.0MeV)70(

MeV) 5(

s

s

10

e+ /108 e- )

Current Simulation x 25.6% N = 0.28(Ee - 3)1.35 - 0.4

)(s

1

N ( N e

LLNL LLNL Fit = 1.4(Ee - 15)AIST

%3MeV)70(

MeV) 10(s

AIST Argonne Mitsubishi

MeV)70(s

0 20 40 60 80 100 1200.1

Electron Energy, Ee (MeV)


B. E. O’Rourke et al., Rev. Sci. Instrum. 82 (2011) 063302

Maximum Slow Positron Yield

500

550

109Y (e+/s)

T > 3270 K

350

400

450

7.500

8.000

8.500

9.00010

107(A

) 108

T > 3270 K3000 K

250

300

350

1066.000

6.500

7.000107

urre

nt, I

e (

2500 K

2000 K

150

200

2505.000

5.500105

ectro

n C

u 2000 K109

108

50

100Ele

1500 K1000 K

500 K

10

107

0 20 40 60 80 1000


500 K

0 20 40 60 80 100



Beam Heating of the Converter

ConductionTw

)/ln(502)(

rrlTTP wb

w

T0

Radiationr1

r2)/ln(5.0 12 rr

e- Tb 2

40

4 d2))(((2r

r rrTrTeP 0

rwed PPIE Cylindrical top-hat


beam

Maximum Slow Positron Yield

500

550

109Y (e+/s)

T > 3270 K

350

400

450

7.500

8.000

8.500

9.00010

107(A

) 108

T > 3270 K3000 K

250

300

350

1066.000

6.500

7.000107

urre

nt, I

e (

2500 K

2000 K

150

200

2505.000

5.500105

ectro

n C

u 2000 K109

108

50

100Ele

1500 K1000 K

500 K

10

107

0 20 40 60 80 1000


500 K

0 20 40 60 80 10070 MeV LINACSCA: 5 – 15 MeV



SummaryPPMA• PPMA:

– PALS measurements possible with a microbeam (30m)

– 2-D and 3-D defect imaging (Beam Energy 0 – 30 kV)

– Extraction of positron microbeam to airExtraction of positron microbeam to air

• New Positron Beamline:

– Currently under construction (scheduled completion this fiscal year Mar 2012)

– Vertical beamlines for PALS and PPMA

– Initially operated using existing LINAC (70 MeV), in future will be synchronous with SCA

• Superconducting Accelerator (SCA)

– High pulse repetition rate, no e+ pulse stretching and chopping


– Low energy but high current, beam heating in the converter/moderator will be a challenge

THANK YOU

and thanks to our collaborators;

P it P b Mi l• Positron Probe MicroanalyzerM. Fujinami (Chiba Uni.)A Uedono (Tuskuba Uni )A. Uedono (Tuskuba Uni.)

• New Positron BeamlineVacuum Products Inc.

S d ti A l t• Superconducting AcceleratorN. Hayashizaki (Tokyo Inst. Tech)E Minehara (Wakasa-Wan Energy Res Centre)


E. Minehara (Wakasa Wan Energy Res. Centre)TIME Inc.

positron probe microanalyzer (ppma) and other accelerator ...maximum slow positron yield 500 550 109...

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