1. M.D. Seliverstov 20-22 February 2013 CERN 1st LA³NET Topical Workshop on Laser Based Particle Sources maxim.seliverstov@cern.ch

2. Contents: Resonant photoionization in-source spectroscopy: advantages and limitations General problems of data analysis (isotopes with I = 0) Correction to the laser power Laser lineshape asymmetry Isotopes with I > 0: hyperfine splitting Relative intensities of hfs lines Saturation hfs levels population redistribution Conclusions and outlook 1st LA³NET Topical Workshop on Laser Based Particle Sources, 20-22 February 2013, CERN

3. Resonant photoionization in-source spectroscopy 3 Isotope shift  A,A’  A,A ’ = F A,A ’ + MS Rms charge radius  A,A’ =   r 2  A,A ’ + C 2   r 4  A,A ’ + … = 0.93   r 2  A,A ’ Relative line position  hyperfine constants A & B  m I, Q S For 208 Pb at T LIS = 2000K:  D = 2.4 GHz (FWHM)  A,A+1 = 1 GHz For Pb isotope chain: Doppler limitation: 1st LA³NET Topical Workshop on Laser Based Particle Sources, 20-22 February 2013, CERN Laser linewidth about 1 GHz

4. 4 Spectra of even-A isotopes of Pb and Po 1st LA³NET Topical Workshop on Laser Based Particle Sources, 20-22 February 2013, CERN Resonant photoionization in-source spectroscopy

5. Fitting function 5 1st LA³NET Topical Workshop on Laser Based Particle Sources, 20-22 February 2013, CERN The simplest case: General form: (Voigt profile) Saturation is possible Laser lineshape can be an asymmetrical function

6. Asymmetry of the fitting function 6 1st LA³NET Topical Workshop on Laser Based Particle Sources, 20-22 February 2013, CERN “standard” Lorentzian: “deformed” Lorentzian:

7. Additional correction to asymmetry of the lineshape 7 1st LA³NET Topical Workshop on Laser Based Particle Sources, 20-22 February 2013, CERN

8. Correction to the laser power 8 Working area 1st LA³NET Topical Workshop on Laser Based Particle Sources, 20-22 February 2013, CERN Optical transition saturation

9. Saturation broadening 9 1st LA³NET Topical Workshop on Laser Based Particle Sources, 20-22 February 2013, CERN

10. Saturation + desynchronization of the laser pulses 10 1st LA³NET Topical Workshop on Laser Based Particle Sources, 20-22 February 2013, CERN Dye lasers with CVL pumping Dye lasers with Nd:YAG pumping: No timing problems Ti:Sa – timing problems again

11. Corrections for desynchronization 1st LA³NET Topical Workshop on Laser Based Particle Sources, 20-22 February 2013, CERN

12. Corrections for desynchronization 1st LA³NET Topical Workshop on Laser Based Particle Sources, 20-22 February 2013, CERN

13. Hyperfine splitting (hfs) 13 Photoionization scheme for Pb 1st LA³NET Topical Workshop on Laser Based Particle Sources, 20-22 February 2013, CERN

14. Hyperfine splitting (hfs) 1st LA³NET Topical Workshop on Laser Based Particle Sources, 20-22 February 2013, CERN

15. Hyperfine splitting (hfs) 1st LA³NET Topical Workshop on Laser Based Particle Sources, 20-22 February 2013, CERN Photoionization scheme for Po

16. Hyperfine splitting (hfs) Position of the hfs lines: Relative intensities (simplified form): 1st LA³NET Topical Workshop on Laser Based Particle Sources, 20-22 February 2013, CERN

17. Hyperfine splitting (hfs) 1st LA³NET Topical Workshop on Laser Based Particle Sources, 20-22 February 2013, CERN

18. Rate equations To take into account the saturation of transitions, pumping processes between hyperfine structure (hfs) components and a population redistribution of the hfs levels the number of photoions N ion for each frequency step was calculated by solving the rate equations for the given photoionization scheme: At t = 0: 1st LA³NET Topical Workshop on Laser Based Particle Sources, 20-22 February 2013, CERN

19. Rate equations ionization N ion F1F1 F2F2 F0F0 F’1F’1 F’2F’2 F’0F’0 F’’ 1 F’’ 2 F’’ 0 NFNF N’F’N’F’ N’’ F’’ W F’F’’ W F’’ F’ W ion W FF’ W F’F 1st LA³NET Topical Workshop on Laser Based Particle Sources, 20-22 February 2013, CERN

20. King plot for Po isotopes King plot for Po atomic transitions 843 nm (our data) and 255 nm. 200–210 Po 1st LA³NET Topical Workshop on Laser Based Particle Sources, 20-22 February 2013, CERN

21. Charge radii of Po isotopes 1st LA³NET Topical Workshop on Laser Based Particle Sources, 20-22 February 2013, CERN

22. Rate equations for the polarized light M F’ -3/2 -1/2 1/2 3/2 F = 1/2  F’ = 3/2 M F -1/2 1/2 1st LA³NET Topical Workshop on Laser Based Particle Sources, 20-22 February 2013, CERN Q = M F – M’ F

23. Rate equations for the polarized light M F’ -3/2 -1/2 1/2 3/2 F = 1/2  F’ = 3/2 M F -1/2 1/2 1st LA³NET Topical Workshop on Laser Based Particle Sources, 20-22 February 2013, CERN Q = M F – M’ F Linear polarization

24. Universal fitting program 1st LA³NET Topical Workshop on Laser Based Particle Sources, 20-22 February 2013, CERN

25. Conclusions The laser ion source is not only a very effective in its normal use as an element- selective tool for producing intense ion beams, but it can be used as a very powerful atomic-spectroscopy tool due to the resonance character of the photoionization (In-Source Laser Resonant Photoionization Spectroscopy). In contrast to other laser spectroscopic techniques, in that case the laser frequency scanning procedure is applied directly within the mass-separator ion source. The main advantage of this technique is its very high sensitivity, nevertheless its spectral resolution is Doppler-limited, therefore the accurate data analysis is of great importance.

26. Thanks for your attention! 1st LA³NET Topical Workshop on Laser Based Particle Sources, 20-22 February 2013, CERN