Update from the LARIS lab
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Transcript of Update from the LARIS lab
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
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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
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46Ti 47Ti50Ti49Ti
48Ti
Time of flight / s
Ion
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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
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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