1. Recent Physics and Future Developments
P.A. Hatherly
J.J. Thomson Physical Laboratory
University of Reading
Whiteknights
Reading RG6 6AF

2. Sources used by the Reading Group
I Like SR
Major International Facilities
SRS, Daresbury, UK
Beamline MPW6.1 PHOENIX
MAX II, Lund, Sweden
Beamline I411
In-house helium lamp
20 and 40 eV photons
Other energies available using Ne, Ar, Kr, Xe

3. Physics Programmes Inner shell ionisation and excitation of molecules
Carried out at DL and MAX
High Resolution Studies of OCS at S 2p and C 1s
Absolute Cross Section Measurements
Recent Final Year Undergraduate Project
Measurement of the absolute absorption cross-section of SF5CF3
Resolving a conflict in values in the literature
Future plans to measure cross sections to allow SR data to be placed on an absolute scale

4. OCS Threshold Electron Studies
At the SRS, Daresbury
S 2p and C 1s excitation of OCS
Threshold electron and ion yield spectra
Fragmentation studies
Coincidence studies between threshold electrons and ions

5. OCS – S 2p Excitations

6. OCS – S 2p Fragments
OCS2+ C+
CO+f
S+f
CO+b O+
S+b

7. OCS – C 1s Excitation

8. OCS – Post C 1s Excitation

9. OCS – C 1s Fragments C+
CO+f
S+f
OCS2+
CO+b
S+b O+

10. OCS Auger Studies At MAX II, Sweden S 2p excitation and Auger spectra
Fragmentation associated with given Auger channels
Coincidence studies between Auger electrons and ions

11. OCS – S 2p Auger Spectrum

12. OCS – S 2p Fragments
OCS2+
S I S+
S II
OCS2+

13. Absorption Cross Sections
Absorption Cross Section of SF5CF3 measured
Disagreement of a factor of 2 between recently reported values at 10.2 eV (H Lyman a)
Final Year Undergraduate Project
Andrew Flaxman
Measured at He I (21.2 eV) and Ne I (16.7 eV, doublet)

14. Cross Section of SF5CF3

15. Future Developments
Recent EPSRC grants to develop attosecond laser technology
Consortium including Reading (Leszek Frasinski), Oxford, Imperial College and Rutherford
Why talk about this at a SR meeting?

16. Attosecond Pulses
Aim of project to generate pulses of the order of 100 as long
Cannot be “optical” wavelengths (period ~ 2 fs)
Need VUV/SXR (eg, ~20 eV, period ~ 200 as)
Hence, need SR optics technology to handle the pulses

17. Attosecond Pulses How to measure the pulse length?
With fs pulses, can use frequency doubling and autocorrelation techniques
With as pulses, need new techniques

18. An Application of PES!
…each generate an identical photoelectron spectrum
Two delayed as x-ray pulse replicas incident on a gas target…
Electron Energy

19. An Application of PES!
…result – interference fringes in the PE spectrum…
…energy levels shifted with time…
…photoelectrons due to each as pulse shifted in energy…
Now add slower, fs, pulse…
Electron Energy
…Details of fringes gives as pulse spectrum and phase information – hence can reconstruct the pulse!
(Quéré et al, PRL 90, 7 (21st Feb 2003))

20. Attosecond Lasers Excellent examples of spin-off technology
VUV and SXR optics well understood in SR
Now being applied in a new area
PES developed as a tool for probing fundamental atomic and molecular properties
Now applied as a tool in it’s own right for a specific technological application
Note this under “Beneficiaries” etc. on your next EPSRC application!

21. Other Developments
Strong possibility of developing a fs laser laboratory at Reading
SRIF funding
High-harmonic generation systems for fs scale time resolved VUV work
Ongoing progress of 4GLS
Exciting possibilities of non-linear VUV phenomena

22. With Thanks: Dr Marek Stankiewicz and Dr Jaume Rius i Riu
SR experiments at Daresbury and MAXlab
Mr Andy Flaxman
Undergraduate Project Student – Cross section data
Dr Leszek Frasinski
Atto- and femtosecond laser development