Implementation of titanium:sapphire lasers at ISOLDE RILIS

Implementation of titanium:sapphire lasers

at ISOLDE RILIS

ISOLDE Workshop 2011

S. Rothe, V.N. Fedosseev, D. Fink, B.A. Marsh, R.E. Rossel, M. Seliverstov and K. Wendt

ISOLDE Workshop 2011 2Implementation of titanium:sapphire lasers at ISOLDE RILIS

Outline

• The RILIS principle

• The new solid-state laser system

• RILIS operation 2011

• In-source laser spectroscopy of Astatine

ISOLDE Workshop 2011 3Implementation of titanium:sapphire lasers at ISOLDE RILISMagnet set to A = 205

The Resonance Ionization Laser Ion Source (RILIS)

• Simple setup at target site: same as surface ion source

• RILIS lasers excite and ionize atomsZ selectiveGround State

Excited States

Rydberg State

Auto-ionizing State

Ionization potential

Laser ionization scheme

At

Laser tuned to Z = 85

205AtIsotope of interest

Laser Ion Sourceline targetlaser beams

ISOLDE Workshop 2011 4Implementation of titanium:sapphire lasers at ISOLDE RILIS

Pump laser: Nd:YAG (532 nm)Repetition rate: 10 kHz, Pulse duration: 9 nsPower: 100 W

The RILIS dye lasers

dye lasers:2 x broadband (6 GHz)1 x narrow band (1 GHz)

Rh6GRh110Pyridin 1Rhod BEozinPyrromethene 567Pyrromethene 597Fluorescein 27Phenoxazone 9 +H2OPhenoxazone 9Styryl 9Styryl 8DCM

550 600 650 700 750 800 85005

101520253035

efficie

ncy (

%)

wavelength (nm) > 10 different dyes used Laser table Jan. 2011

After CVL removal 2010

ISOLDE Workshop 2011 5Implementation of titanium:sapphire lasers at ISOLDE RILIS

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009

2010

0

500

1000

1500

2000

2500

Year

Ope

ratio

n pe

r yea

r (h)

Realistic curve for one laser system

demand

RILIS operation 1994 to 2010

ISOLDE Workshop 2011 6Implementation of titanium:sapphire lasers at ISOLDE RILIS

LISOLLouvain-la-Neuvegas cellrep. rate <200Hzdye laser

ISOLDE, Genevahot cavityrep. rate 10 kHzdye laser

RILISFURIOSJyväskylägas cellrep. rate ~10 kHzti:sa & dye laser

ORNLOak Ridge (off-line)

hot cavity rep. rate ~10 kHzti:sa laser

TRILISVancouverhot cavity rep. rate ~10 kHzti:sa laser

TIARATakasakihot cavityrep. rate 300Hzdye laser

? gas catcher ?

RIKEN

? hot cavity ?

ALTO Selection only. updated from C. Geppert (2007) V.Fedosseev (2010)

? hot cavity ?

SPES

GISELE Caen (off-line)

rep. rate ~10 kHzti:sa laser

Gatchinahot cavityrep. rate ~10 kHzdye laser

PNPI

RISIKO Mainz (off-line)

rep. rate ~10 kHzti:sa laser

Laser ion sources World-Wide

ISOLDE Workshop 2011 7Implementation of titanium:sapphire lasers at ISOLDE RILIS

Dye Ti:SaActive Medium > 10 different dyes =1 Ti:sapphire crystalcondition of aggregation liquid (org. solvents) solid-stateTuning range 540 – 850 nm 680 – 980 nmPower < 12 W < 5 WPulse duration ~8 ns ~50 nsSynchronization optical delay lines q-switch, pump power# of schemes developed 47 37Maintenance renew dye solutions ~ none

Comparison dye vs. Ti:Sa system

200 300 400 500 600 700 800 900

0.10.20.51.02.05.0

10.0

wavelength nm

Ti:Sa

Dye

2x Ti:Sa2x Dye

3x Ti:Sa

4x Ti:Sa3x Dye

550 600 650 700 750 800 850 900 950

0

5

10

15

20

25

30

35

effic

ienc

y(%

)

wavelength (nm)

Dye

Ti:Sa

Ti:Sa system is complementary

ISOLDE Workshop 2011 8Implementation of titanium:sapphire lasers at ISOLDE RILIS

The Ti:Sa laserend mirror etalon birefringent tuner

laser crystal

output couplerpump beam

3d model• Mainz-Type• Design optimized for

on-line operations

Prototype• Machined at Mainz

University workshop

Serial production

Lasing medium: • solid-state Ti doped

sapphire (Ti:Al2O3)• Hardness 9

Serial production• 3 Ti:Sa modules available

ISOLDE Workshop 2011 9Implementation of titanium:sapphire lasers at ISOLDE RILIS

The RILIS Ti:Sa lasers

Wavelength tuning range:• Fundamental (w) 690 - 940 nm (5 W) • 2nd harmonic (2w) 345 - 470 nm (1 W)• 3rd harmonic (3w) 230 - 310 nm (150 mW)• 4th harmonic (2w) 205-235 nm (50 mW)

Change of mirror sets in resonatorNo amplifier yet availableNo ageing

700 750 800 850 900 9505

10

15

20

25

30

lass

ing

effic

ienc

y(%

)

wavelength (nm)

SP4440SP4444SP0000SP1000SP1111SP1110

100 mm

Pump laser: Nd:YAG (532 nm)Repetition rate: 10 kHzPulse length: 180 nsPower: 60 W

Ti:Sa lasers:Line width: 5 GHzPulse length: 30-50 ns

6 resonator mirrorsets cover the Ti:Sa range

ISOLDE Workshop 2011 10Implementation of titanium:sapphire lasers at ISOLDE RILIS

RILIS Dye Laser System GPS/HRS

Target & Ion Source

l – meterDye 2 SHG

Narrowband Dye

THGDye 1

Nd:YAG

10 kHz Master clock

Dye RILIS

ISOLDE Workshop 2011 11Implementation of titanium:sapphire lasers at ISOLDE RILIS

RILIS Dye Laser System GPS/HRS

Target & Ion Source

RILIS Ti:Sa Laser System

pA – meter

Faraday cup…

SHG/THG/FHG

l – meter

Ti:Sa 2

l – meterDye 2 SHG

Narrowband Dye

THGDye 1

Ti:Sa 1

Ti:Sa 3

Nd:YAG

Nd:YAG

10 kHz Master clock

Delay generator

LabVIEW based DAQ

Ti:Sa & Dye RILIS

ISOLDE Workshop 2011 12Implementation of titanium:sapphire lasers at ISOLDE RILIS

RILIS in operation

ISOLDE Workshop 2011 13Implementation of titanium:sapphire lasers at ISOLDE RILIS

RILIS in operation

ISOLDE Workshop 2011 14Implementation of titanium:sapphire lasers at ISOLDE RILIS

Sm Ga Mg At Pb Dy Nd Pr Ag Tl Cd Mn Ni Dy Yb Zn

89 101146

269221

35

110

4

92

231 241

390348

6013

407real plan

RILI

S op

erati

on 2

011

(h)

RILIS operation 2011

Ion beams of 16 elements were produced since beginning of the running period: • 2573 h for on-line experiments • Ti:Sa system used already with 9 elements• Some additional tests only feasible because of the ‘spare’ laser system

Ti:Sa involvement

ISOLDE Workshop 2011 15Implementation of titanium:sapphire lasers at ISOLDE RILIS

Ti:Sa only mode100 W Nd:YAG laser available for non-resonant ionization

Mixed modeCombination of dye and Ti:Sa

Backup modedye and Ti:Sa are

exchangeable

Highest efficiencies New RILIS elements Reduction in down time

New modes of operation – The Dual RILISCondition for dual operation: Temporal synchronization of the two laser systems

ISOLDE Workshop 2011 16Implementation of titanium:sapphire lasers at ISOLDE RILIS

a) Photoionization threshold : 75129(95) cm-1

b) Scan for 2nd step transitions (at TRIUMF)

c) Verification of levels, yield measurements

d) Scan of ionizing laser: converging Rydberg levels allow precise determination of the IP

532

nm

224

nm

216

nm31

2 - 3

35 n

m

609-

645

nm

a) b) c)

795

nm

532

nm

44550 cm-1

0 cm-1

46234 cm-1

57157 cm-1

57269 cm-1

57277 cm-1

58805 cm-1

75151 cm-1

710-

915

nm

d)

E𝑛=E IP−RM

(𝑛−𝐴+ 𝐵(𝑛−𝐴 )2 )

2

Rydberg-Ritz formula

EIP(At) =75151(1) cm-1

preliminary

16150 16200 16250 16300 16350

0

10

20

30

ion

curr

ent

(pA

)

wavenumber (cm -1)

10 36

preliminary

0 5 10 15 20 25 30 35

15800

16000

16200

wav

enum

ber

(cm

-1)

n'

0 10 20 30

-0.50.0

0.5

resi

dual

s(c

m-1)

n'

Phys. Rev. Letter in preparation

At in-source spectroscopy

ISOLDE Workshop 2011 17Implementation of titanium:sapphire lasers at ISOLDE RILIS

Summary• A complementary second laser system of Ti:Sa lasers was installed at RILIS• RILIS operated smoothly >2500 h in 2011• Dual RILIS (Combined dye and Ti:sapphire laser system) is in regular

operation• In-source laser spectroscopy of Astatine led to development of an

efficient ionization scheme and first and precise determination of the ionization potential

Outlook / Comments• RILIS scheme development could become partly opportunistic (e.g. astatine)• Machine protection, monitoring and remote control progressing• For Ti:Sa-only schemes RILIS could operate in on-call mode very soon• RILIS scheme database (cern.ch/riliselements) in beta phase

ISOLDE Workshop 2011 18Implementation of titanium:sapphire lasers at ISOLDE RILIS

Acknowledgements

KTH – Royal Institute of Technology &Knuth and Alice Wallenberg FoundationStockholm, Sweden

CERN, EN-STI

University of Mainz, Working group LARISSAMainz, Germany

The Wolfgang-Gentner-Programme of the Bundesministerium für Bildung und Forschung (BMBF)

RILIS - Team