ah 0v

Detector

Fion

z0

R. J. Peláez, C. Blondel, C. Delsart and C. DragLaboratoire Aimé-Cotton, Centre national de la recherche

scientifique, batiment 505,Univ. Paris-sud, F-91405 Orsay cedex, France

Photodetachment microscopy with a pulsed laser

Experiment set-up

qFa

0max 2 azR

23

032

aN

Interfrangesdistance

a

z

NR

i3

00max 3

Pulsed laser

7

6

5 4

3

2

1

8

9

10

11

12

13

 1 : Source and simple lens doublet (“Einzellens") 2,5,9,10 : Deflection plates3,6,8 : Simple lenses

4 : Wien filter7 : Deflection  11 : Focalisation quadrupole 12 : Deceleration plates13 : Interection zone

C

D

F

U

Pumped QCW20 Hz, 515 nm

Ti:SaQCW, 150 µs

Dual polarizationstabilized He-Ne

Sigmameter QCW

Lambdameter WSUuncertain. +/- 0.041 m-1

Frequency doubled Nd:YAG 25 mJ @ 532 nm

Pulsed Ti:Sa~ 10 mJ @ 810 nm

BBO

~ 1 mJ @ 405 nm 15 ns

L. Cabaret and C. Drag, Eur. Phys. J. Appl. Phys. 37, 65 (2006)

L. Cabaret, Appl. Phys. B 94, 71 (2009)

1S0

2P3/2

F1 = 5/2

F2 = 1F2 = 2F2 = 3

F2 = 4

I [F2]=2 F2 +1

14.097 m-1

6.5575 m-1

2.46 m-1

eA=2467287(3) m-1

Ele

ctro

n C

oun

t

Radius (mm)

2467275

2467280

2467285

2467290

2467295

0 100 200 300 400Laser pulse energy (microJ)

Ele

ctr

on

aff

init

y (

m-1

)Ele

ctro

n a

ffinit

y (

m-1)

Laser pulse energy (µJ)

Quantum parameters :

Number of rings

Classical parameters

Radial current density

Principle: Y.N. Demkov et al., JETP Lett. 34, 403 (1981)

Photodetachment microscopy: C. Blondel et al., Phys. Rev . Lett. 77, 3755 (1996)

Photoionization microscopy: C. Nicole et al., Phys. Rev . Lett. 88, 133001 (2002)

Molecular photodetachment microscopy : C. Delsart et al., Phys. Rev . Lett. 89, 183002 (2002)

Highest height

Maximum radius

32

0 2mqF

0 = 0.045 ma = 0.35 m

R

F = 427 Vm-1

= 0,926 ± 0,002 cm-1

Rmax

j

14

15

14 : Laser 15 : Column of constant F16 : MCP17 : Phosphor screen18 : CCD

negative

ion

neutral atom

h

eA

18

16

17

Accumulation Barycenter

Photodetachment microscopy

Results : electron affinity of 127I

2

'

2

1

21

U

F

C

DhA

Tunable single longitudinal mode.Long & short time stabilization

Nanosecond pulse

Uncertainty ≈0.8 m-1

Energy ≈ 400J

Main proprieties

1980 1990 2000 2010Year

Ele

ctro

n A

fin

ity

(eV

)

3.05899

3.05904

3.05909

3.05914

3.05919

Experiment

2467275

2467280

2467285

2467290

2467295

0 20 40 60 80 100

Photoelectron average energy (m-1)

Ele

ctro

n afi

nity

(m

-1)

2.7

2.8

2.9

3.0

3.1

3.2

1980 1990 2000 2010

Year

Ele

ctro

n A

fin

ity

Theory

Experiment

Ele

ctro

n A

ffinit

y (

eV

)

Ele

ctron A

ffinity

(eV

)

Ponderomotive effect : electron oscillations in electromagnetic waves.

2

22

P4 m

EqU

R. J. Peláez et al. J. Phys. B. 42, 125001 (2009)

eA(127I) = 24672.867 (28) cm-1

= 3.0590453 (36) eV

Ponderomotive effect has been negligible, for two reasons:i) Blue wavelength (405 nm

for I-)ii) Low energy ≈ 400µJ

XXVI International Conference on Photonic, Electronic, and Atomic Collisions.Kalamazoo, Michigan 22 - 28 July 2009

a

z

RRj

0

2

0

2

4

1)(

Ai