Demonstration of MOTRIMS Probing Capability

Hai Nguyen, Richard Brédy, Howard Camp, Takaaki Awata, Kyle Wilson,

Brett DePaola.

OUTLINE

Motivation

Experimental Setup

Review of earlier results

New Results

MOTIVATION

Collisions with excited target

Cross-section measurements provide rigorous test for TC-AOCC.

Optimizing MOTRIMS capabilities.

EXPERIMENTAL SETUP

PREVIOUS RESULTS7 keV Na+ + Rb (5s, 5p)

-5

-4

-3

-2

-1

0

4d 2D5/2

, 4d2D3/2

4f 2F7/2

, 4f2F5/2

5s 2S1/2

4p 2P1/2

, 4p 2P3/2

23Na

4s 2S1/2

3d 2D5/2

, 3d2D3/2

3p 2P1/2

, 3p 2P3/2

3s 2S1/2

12f

4d 2D3/2,5/2

5p 2P3/2

5s 2S1/2

87Rb

Pote

ntia

l Ene

rgy

(eV)

-3 -2 -1 0 1 2 30

2000

4000

6000

8000

10000

12000

14000

16000

4p*

3d*

4d*

5s*

3d

4s*

3p

3p*

3s

Coun

ts

Q value (eV)

PREVIOUS RESULTS7 keV Na+ + Rb (5s, 5p)

-3 -2 -1 0 1 2 30

1000

2000

3000

4000

5000-3 -2 -1 0 1 2 3

0

5000

10000

15000

5s-3p

5s-3sCo

un

ts

Q value (eV)

Off

y0 786 ±0xc1 0.96112 ±0.00163w1 0.21422 ±0.00328A1 1137.9999 ±15.01743xc2 0.4429 ±0.00137w2 0.21877 ±0.00278A2 1390.17651 ±15.17554

5p-3p5s-3s

5s-3p

5p-3d5p-4p

5p-4s

Co

un

ts

Tot

-3 -2 -1 0 1 2 30

5

10

15

20

Q Value (eV)

TAC

Tim

e (

s)

5.000

6.776

9.183

12.44

16.86

22.85

30.97

41.97

56.88

77.09

104.5

141.6

191.9

260.0

PREVIOUS RESULTS7 keV Na+ + Rb (5s, 5p)

offonp

onss

offs TnnA )(

ons

onp

onp

ons

s

p

A

A

n

n

ononss

ons TnA

off islaser when Time T

on islaser when Time T

off islaser when s from capture of Amplitude A

on islaser when s from capture of Amplitude A

on islaser when state iin atoms ofnumber n

off

on

offs

ons

th

i

on

off

offs

ons

ons

onp

onp

T

T

A

A

nn

nf 1

ononpp

onp TnA

PREVIOUS RESULTS7 keV Na+ + Rb (5s, 5p)

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.400

1

2

3

4

5

P /

S

Excited State Fraction

P /

S

Average P /

S

-3 -2 -1 0 1 2 30

2000

4000

6000

8000

10000

12000

14000

16000

4p*

3d*

4d*

5s*

3d

4s*

3p

3p*

3s

Coun

ts

Q value (eV)

PREVIOUS RESULTSCompared to calculation

1 2 3 4 5 6 7 81

10

100

Collision Energy (keV)

1 2 3 4 5 6 7 81

10

100

Collision Energy (keV)

ss

ps

35

35

sp

pp

45

35

PREVIOUS RESULTS7 keV Na+ + Rb (5s, 5p)

-3.0 -2.5 -2.0 -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 2.0 2.5 3.00.0000

0.0005

0.0010

0.0015

0.0020 Matrix1

5s-3d

7 keV Na++Rb(5s),Rb(5p) Na*+Rb+

5s-3p

5p-4d

5p-4s

5p-3p

5s-3s

2.000

3.431

5.886

10.10

17.32

29.72

50.99

87.48

150.1

257.5

441.7

757.8

1300

Q value (eV)

Sca

tterin

g A

ngle

(ra

d)

PREVIOUS RESULTSCompared to calculation

0.0 0.5 1.0 1.5 2.00

2

4

6

8

10

12

14

sin x

DC

S (1

0-1

1cm

2 )

0.0 0.5 1.0 1.5 2.00

2

4

6

85P - 3P

E = 2 keVE = 5 keVE = 7 keV

E (mrad)

Expt

. DC

S (1

0-1

1cm

2 )

0 1 2 3 4 50

2

4

6

8

10

12

sin x

DC

S (1

0-1

3cm

2 )

E (mrad)

0 1 2 3 4 50

2

4

6

8

10

E = 5 keV

E = 2 keV

E = 7 keV

5S - 3P

Expt

. DC

S (1

0-1

3cm

2 )

(keV mrad) (keV mrad)

5p-3p 5s-3p

Other Collision Systems: Difficulty

-6

-5

-4

-3

-2

-1

012f

4d 2D3/2,5/2

5p 2P3/2

5s 2S1/2

3p 2P1/2

, 3p 2P3/2

3d 2D5/2

, 3d2D3/2

3s 2S1/2

2p 2P1/2

, 2p 2P3/2

2s 2S1/2

7Li87Rb

Poten

tial E

nerg

y (e

V)

-5

-4

-3

-2

-1

012f

4d 2D3/2,5/2

5p 2P3/2

5s 2S1/2

12f

87Rb

4d 2D3/2,5/2

5p 2P3/2

5s 2S1/2

Pote

ntia

l Ene

rgy

(eV)

CURRENT RESULTS7 keV Li+ + Rb (5s, 5p)

-3 -2 -1 0 1 2 30

5

10

15

20

Q Value (eV)

Tim

e (s

)

1.000

1.886

3.557

6.707

12.65

23.85

44.99

84.84

160.0

-3 -2 -1 0 1 2 30

3000

6000

9000

5s-3s

5p-3p

5s-2p 5p-3s

5p-2p

5s-2s

Coun

ts

Q Value (eV)

total

7 keV Li+ + Rb

Multi-Projectile Source

0 1000 2000 3000 4000 5000 6000 7000

100

1000

10000

7Li+ + Rb

6Li+ + Rb

23Na+ + Rb

Cou

nts

TOF (channels)

Total TOF Spectrum

Probe (Na contaminant)

From Previous Results Na+From Na+ Contaminant

MOT excited state fraction

p

son

off

offs

onp

offs

onp

ons

onp

onp

T

T

A

A

n

n

nn

nf

7 keV Na+ Contaminant

p

son

off

offs

onp

offs

onp

sp

p

T

T

A

A

n

n

nn

nf

04.019.0 f

-3 -2 -1 0 1 2 30

50

100

150

200

250

300

5s-3p

5p-4s

5p-3p

5s-3s

Coun

ts

Q Value (eV)

Total

Na+ Contaminant in Li+ source

p

son

off

offs

onp

offs

onp

ons

onp

onp

T

T

A

A

n

n

nn

nf

From measurements of Li+ Unknown Li+

Cross Sections 7 keV Li+ + Rb

35.048.3 s

p

023.0828.025

s

ps

091.0125.035

p

pp

Waiting for TC-AOCC results

076.0172.025

s

ss

022.0658.035

p

sp

045.0217.025

p

pp

7 keV Li+ + Rb Scattering Angle Information

0 200 400 600 800 10000

1000

2000

3000

4000

5000

6000

7000

8000

Coun

ts

Scattering Angle (rad)

5p-3p, 5s-2p, 5p-3s

-3 -2 -1 0 1 2 30

500

1000

1500

2000

5s-2s

5p-2p

5p-3s5s-2p5p-3p

Q Value (eV)

Scatt

erin

g An

gle (

rad)

1.000

2.400

5.759

13.82

33.17

79.59

191.0

458.4

1100

7 keV Li+ + Rb Scattering Angle Information

0 200 400 600 800 10000

500

1000

1500

2000

2500

Coun

ts

Scattering Angle (rad)

5p-2p, 5s-2s

Grouped scattering angle information are hard to extrapolate (Rb + Rb).

Theoretical Comparison not trustworthy.

Using a weighted method to deduce individual channel scattering angle information.

Weighted Method (Rb+ + Rb)

Consider an even more extreme case: Rb+ + Rb collision system, where s-s & p-p are completely overlapped.

Because lasers are turned

on/off, we know exactly when capture from 5p not possible.

Weighted by excited state fraction we deduce [Qvs]ss & [Qvs]pp separately.

1.59-1.59 0

TA

C ti

me s

Q Value (eV)5s-5p

5p-5s

5s-5s5p-5p

0

20

5s

Weighted Method (Rb+ + Rb)

onpp

onss

ontotal NNN

onpp

onss

ontotal NNN

)1( fNT

TN off

ssoff

ononss

1.59-1.59 0

TA

C ti

me s

Q Value (eV)5s-5p

5p-5s

5s-5s5p-5p

0

20

5s

)1(

1fN

T

TN

fN off

ssoff

onontotal

onpp

)1( fNT

TN off

ssoff

ononss

7 keV Li+ + Rb Scattering Angle Information

-3 -2 -1 0 1 2 30

500

1000

1500

2000

5p-3p 5s-2s5p-2p

5p-3s5s-2p

Q Value (eV)

Scatt

erin

g An

gle(

rad)

1.000

2.306

5.318

12.26

28.28

65.23

150.4

346.9

800.0

-3 -2 -1 0 1 2 30

500

1000

1500

2000

5s-2s

5s-2p

Q Value (eV)

Scatt

erin

g An

gle(

rad)

1.000

2.080

4.325

8.996

18.71

38.91

80.92

168.3

350.0

Laser on Laser off

7 keV Li+ + Rb Scattering Angle Information

0 200 400 600 800 10000

200

400

600

800

1000

Co

unts

Scattering Angle (rad)

NssON

0 200 400 600 800 10000

500

1000

1500

2000

2500

3000

Coun

ts

Scattering Angle (rad)

NppON

DEVELOPMENTS

Double (multiple) species pellets development technique.

Diode lasers control and implementation.

Technique of analysis.

SUMMARY

Multiple species pellets along with extremely high resolution in Q-value allow us to make ‘in situ’ measurements of excited state fraction and relative cross sections.

Kinematically complete collisions study for energetically degenerate channels.

MOTRIMS is a powerful tool for ion-atom collisions.

SIMPLE OPTICS LAYOUT

TRAP

REPUMP

Sat abs

Sat abs

F=40cmAOM 80MHz Com

TRAPPING OPTICS

Blocker

F=40cm

O I/2

O I

/2

DAVLL

DAVLL

SIMPLE OPTICS LAYOUT

PBS

PBS

/2

/2

/4

/4

/4

/4

/4

/4

MirrorM

irror

Mirror

Mirror

Mir

ror

Mirror

From AOM

Projected TOF

0 20 40 60 80 100 120 1404.5x10-5

5.0x10-5

5.5x10-5

6.0x10-5

6.5x10-5

7.0x10-5

7.5x10-5

8.0x10-5

8.5x10-5

9.0x10-5

Cs133

Rb85

K39

Na23

Li6

TO

F s

Mass a.u.

2 KeV 5 KeV 7 KeV

6 8.268E-5 8.548E-5 8.623E-523 7.538E-5 8.086E-5 8.232E-539 7.087E-5 7.801E-5 7.991E-585 6.162E-5 7.216E-5 7.497E-5133 5.442E-5 6.761E-5 7.112E-5

--

Mass a.u. 2 keV s 5 keV s 7 keV s

STIRAP Application

STIRAP Application

MOTRIMS will allow us to monitor relative population.

Gain insights into non-destructive STIRAP physics.

STIRAP Sample Results

-2.0 -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 2.0

0

1000

2000

3000

7 keV Na+ + Rb(5s),Rb(5p),Rb(4d)

Na(

4d)

Na(

4p)

Na(

3d)

Na(

3p)

Na(

4s)

Na(

4p)

Na(

3d)

Na(

4s)

Na(

3p)

Na(

3s)

Capture on Rb(5s)Capture on Rb(5p)Capture on Rb(4d)

Cou

nts

Q Value (eV)

0 2 4 6 8 100.0

500.0

1000.0

1500.0

2000.0

2500.0

3000.0Laser ONLaser ON Laser OFFLaser OFF

Rb5s Rb5p Rb4d

Coun

t

Time (ms)