Update from the LARIS lab

Marica Sjödin

19.2 19.4 19.6 19.8 20.0 20.2 20.4

46Ti

47Ti

50Ti49

Ti

48Ti

Time of flight / s

Ion

Sig

nal /

AU

Auto-ionizingstate

1

2

3

Isolde workshop, November 2008

Primary objectives:

Investigate new ionization schemes (free from ISOLDE scheduling) Improve upon current schemes that rely on non-resonant ionization

- search for auto-ionizing states Prepare for RILIS transition Solid State Laser system

- different wavelength range (532 nm and 355 nm pumped dye lasers)

Secondary objectives:

Investigate RILIS selectivity improvements- HFS measurements (isomer selectivity)- Hot cavity optimization / material testing

Tertiary objectives:

Questions related to fundamental atomic spectroscopy, e.g. accurate determination of atomic ionization potentials.

The The LARIS LARIS LaboratoryLaboratory - Introduction- Introduction

Funding: Knut and Alice Wallenberg Foundation

CERN/KTH collaboration

2-step: (1 resonance) (2 resonance)

3-step: 2 resonance) (3 resonance)

1 2H He

3 4 5 6 7 8 9 10

Li* Be B C N O F Ne11 12 13 14 15 16 17 18

Na* Mg Al Si P S Cl Ar19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36

K* Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54

Rb* Sr* Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe55 56 57 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86

Cs* Ba* La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn87 88 89 104 105 106 107 108 109 110 111 112

Fr* Ra Ac Rf Ha Sg Ns Hs Mt*Useful RILIS ionization would require SI suppression (new cavities or LIST)

58 59 60 61 62 63 64 65 66 67 68 69 70 71Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu

90 91 92 93 94 95 96 97 98 99 100 101 102 103Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr

Laser ionisation not feasible with RILIS lasersIonisation scheme in use at ISOLDEGood ionisation efficiencyCurrently using non resonant final step - want improved efficiencyRILIS feasible - Atomic data known but ionisation scheme not testedElement not released from ISOLDE target

LARIS is an offline development lab for RILIS ISOLDE

Separate laser system

Separate atomic scource

(only stable isotopes)

The The LARIS LARIS LaboratoryLaboratory

Measure relative efficiecies of ionization schemes

Systematic study of auto-ionising states

New ionisation schemes for currently unavailable elements

Replace schemes that require CVL pumping @ 511 nm

- Immediate tasks- Immediate tasks

or or...

The The LARIS LARIS LaboratoryLaboratory - overview- overview

Nd:YAG 3 Dye laser

Nd:YAG 2 OPO 2

Nd:YAG 1

WavelengthMeter

22generatorsgeneratorsWith tracking systemWith tracking system

OPO 1

Auto-ionizingstate

IP

3

2

1

Atomic beamOven / Laser ablation source

TOF MS

Detector

Lecroy Waverunner oscilloscope

Integrated ion signal

Pulse, Delay generator

PD

Continuum PowerLite 7010 + OPO Mirage + Continuum UVTTuning range: 720 - 920 nm (fund.), 360 - 460 nm (2)

532 nm, 10 Hz400 mJ

The The LARIS LARIS LaboratoryLaboratory - Lasers- Lasers

80 mJ @750nm 10 mJ @ 425nm

Spectra Physics Quanta-Ray PRO 230-10 + MOPO HF + FDO-970Tuning range: 450 - 690 nm (signal), 735 - 1680 nm (idler), 220 – 440 (2)

355 nm, 10 Hz400mJ

MOPO-HF

The The LARIS LARIS LaboratoryLaboratory - Lasers- Lasers

70 mJ @500nm 7.5 mJ @250nm

MOPO-HF

The The LARIS LARIS LaboratoryLaboratory - Lasers- Lasers

”Easily” tuneable over avery wide -region (with some gaps)

Handy when probing for autoionising states

Spectra Physics Quanta-Ray PRO 230-10 + MOPO HF + FDO-970Tuning range: 450 - 690 nm (signal), 735 - 1680 nm (idler), 220 – 345, 365 - 440 (2)

Complicated (and expensive!)to set up

Need good tables

The The LARIS LARIS LaboratoryLaboratory - Lasers- Lasers

Quantel YAG Pump laser

20 Hz

Pulse energy:

350 mJ (1064 nm) 160 mJ (532 nm) 60 mJ (355 nm) Pulse duration @1064 nm: 4.4 ns

Quantel Brilliant (“Banana laser”) Nd:YAG with 2 and 3 unitsLumonics HD-500 Dye laserDye tuning ranges: 390 - 850 nm (fund.), >200 nm(2)

The The LARIS LARIS LaboratoryLaboratory

Two complementary units:

Laser ablation sourceWith Time Of Flight MS

Thermal atomic beam unitTOF MS will be added

The The LARIS LARIS LaboratoryLaboratory - Time of flight mass spectrometer- Time of flight mass spectrometer

Ablationchamber

To acquire higher resolution laser spectra for specific isotopesTo acquire higher resolution laser spectra for specific isotopesMeasure isotope shifts for stable isotopesMeasure isotope shifts for stable isotopesMeasure HFS for different atomic transitions in various ionization schemesMeasure HFS for different atomic transitions in various ionization schemes(Feasibility study for (Feasibility study for isomer separationisomer separation))

Ablation chamber and gas transport of atoms into interaction region:Ablation chamber and gas transport of atoms into interaction region:

Ulf Sassenberg - Summer 2007

TOF tube

To TOF tube

5 cm, 6 mm

The The LARIS LARIS LaboratoryLaboratory - Time of flight mass spectrometer- Time of flight mass spectrometer

Ablation laser

Ablation unit

New wave POLARIS 350mJ @ 532 nm

Carrier gasAr

Pulsed nozzle

Sample rod

Ionisation lasers

19.2 19.4 19.6 19.8 20.0 20.2 20.4

46Ti 47Ti50Ti49Ti

48Ti

Time of flight / s

Ion

Sig

nal /

AU

The The LARIS LARIS LaboratoryLaboratory - Time of flight mass spectrometer- Time of flight mass spectrometer

R = ~ 200m

m

WavemeterLM 007

powermeter2641.5 2642.0 2642.5 2643.0 2643.5

Probe energy / cm-1

Inte

grat

ed Io

n S

igna

l / A

U

Photodiode

Signal from detector

Wavelength measurement to computer

If the wavelenght is ”good” thenGet parameters from oscillatorAnd from powermeter(s)

LABView interfaceSelect parameters to be recordedSet tolerance levels for Start program

The The LARIS LARIS LaboratoryLaboratory - Data Acquisition system- Data Acquisition system

Oscilloscope (Lecroy Waverunner 104Xi)Define parameters

P1

P2

P1 P2

The The LARIS LARIS LaboratoryLaboratory - First test of RILIS ISOLDE relevant element - Mn- First test of RILIS ISOLDE relevant element - Mn

Why Mn?

A new ionisation scheme was urgently needed

When the current Mn scheme was developed at RILIS the yield was found to be better when a weak transition was used in the second step – Suspect an accidental resonance

1 2H He

3 4 5 6 7 8 9 10

Li* Be B C N O F Ne11 12 13 14 15 16 17 18

Na* Mg Al Si P S Cl Ar19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36

K* Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54

Rb* Sr* Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe55 56 57 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86

Cs* Ba* La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn87 88 89 104 105 106 107 108 109 110 111 112

Fr* Ra Ac Rf Ha Sg Ns Hs Mt*Useful RILIS ionization would require SI suppression (new cavities or LIST)

58 59 60 61 62 63 64 65 66 67 68 69 70 71Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu

90 91 92 93 94 95 96 97 98 99 100 101 102 103Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr

CVL

? Autoionising state

3d54s2 6S5/2

3d54s4p 6PJ

7/25/23/2

3d7 4P5/2

One colour signal √Two or three colour signal

285.2 nm

3d54s5s 6S5/2

628.3 nm

510.6 nm

732.6 nm

Interesting – what is that accidental resonance?

What happens when we replace CVL with YAG?

Full test of our entire system

Ti CVL

? Autoionising state

3d54s2 6S5/2

3d54s4p 6PJ

7/25/23/2

3d7 4P5/2

2-step: (1 resonance)

√

Cu

2-step: (2 resonance) √One colour signal √

Two or three colour signal

285.2 nm

3d54s5s 6S5/2

628.3 nm732.6 nm

The The LARIS LARIS LaboratoryLaboratory

We can trust our method for overlapping the beams

But...

We recently found that we were not using optimal delays between gas pulse, ablation laser and ionisation lasers

And we found that our wavemeter can not be trusted in the UV region

So we will try again

The The LARIS LARIS LaboratoryLaboratory - Thermal atomic beam unit- Thermal atomic beam unit

Plan of the first thermal atomic beam unit in LARIS built by Fabian Österdahl

Ceramic oven Watercooled flangeChanneltron detector close to the interaction region

We are now in the process of making some modifications to begin using it for spectroscopy

Laser window

Oven port

The The LARIS LARIS LaboratoryLaboratory - Thermal atomic beam unit- Thermal atomic beam unit

Channeltron

Ceramic oven replaced with Tantalum oven

Same flange – Replace insulator and make full use of water cooling

20 cm extension to increase the distance to channeltron

The The LARIS LARIS LaboratoryLaboratory - Testing Reflectivity of Molybdenum mirror at higher temperatures- Testing Reflectivity of Molybdenum mirror at higher temperatures

Heated mirror up to 1000 °C

No change in reflectivity has been detected

• Working Lasers• Timing system• Working Laser ablation TOF MS• Laser Ions – Ti, Cu, Mn, Ca 1 and/or 2 coulour signals• Data Aquisition: , Oscilloscope can function as 8 Boxcar modules,

laser power measurement.

FUTURE plans• Reassemble oven unit • Measurements from thermal ABU to complement laser ablation

scource• TOF for oven ABU• Continue with Mn and other elements...

The The LARIS LARIS LaboratoryLaboratory - SUMMARY- SUMMARY

FEDOSSEEV, Valentine (CERN)LINDROOS, Mats (CERN)LOSITO, Roberto (CERN)MARSH, Bruce (CERN)

BERG, Lars-Erik (Royal Institute of Technology)LAUNILA, Olli (Royal Institute of Technology)PAUCHARD, Thomas (Royal Institute of Technology)RAFIEE, Mohammad (Royal Institute of Technology)SJÖDIN, Marica (Royal Institute of Technology)TRANSTRÖMER, Göran (Royal Institute of Technology)VANNESJÖ, Johanna (Royal Institute of Technology)ÖSTERDAHL, Fabian (Royal Institute of Technology)

Funding: Knut and Alice Wallenberg Foundation

SASSENBERG, Ulf (Stockholm University)

POHJALAINEN, Ilkka (Helsinki University)

The The LARIS LARIS LaboratoryLaboratory - PEOPLE- PEOPLE