Research perspectives
IAPP: COLDBEAMS 7th October, 2013, Paris
Andy McCulloch
European Research Council: ERC-StG- COLDNANO
Marie Curie Industry-Academia Partnerships and Pathways: FP7-PEOPLE-2009-IAPP
Orsay Physics
• Matthieu Viteau• Bernard Rasser• Pierre Sudraud
Laboratoire Aimé Cotton
• Yoann Bruneau• Guyve Khalili
• Andy McCulloch• Isam Manai
• Mehdi Hamamda• Hans Lignier• Pierre Pillet
• Daniel Comparat
• Justine Houplin• Roger Azria
• Lionel Amiaud• Anne Lafosse
Institut des sciences molécullaires d’Orsay
Controlled Chemistry:Nanofunctionalisation of surface molecules
• The ability to control and orientate chemical reactivity in the condensed phase
• Many applications, particularly in biotechnology and biosensing
• Electrons drive bond cleavage, creating highly reactive molecules
• Local interaction(s) lead to the synthesis of new molecules or bonding with the surface
Tuning E(e-) for successive Dissociative Electron Attachement
• Current source: 5 µA on (1 mm²) (1 A/m²) with 1 eV resolution
• New source: 10 pA on (10 µm)² (105 A/m²) with 1 meV resolution
Controlled Chemistry
Gold
Terminal group
spac
er
Aro
mat
icA
lkyl
1eV6eV Deposited molecular film
9eV
Controlled chemistry
• After surface modification, the surface is analysed using HREELS
• Low current source + serial detection = Long acquisition times (hours)
• Energy range: 0-2eV, few meV resolution
Can we help, not only with functionalisation, but additionallyHREELS?
6eV beam
0-2 eV beam with meV resolution
Functionalisation/HREELS
First steps
• Produce electrons!
• Measure beam properties: emittance, etc.
Energy spread
• Need to know the energy spread– Spectrometer
Can we perform other experiments simultaneously?
Deterministic single ion source
• Huge demand for sources of single ions– Large number of applications: Quantum
computation, ion implantation, etc.
• Rydberg atoms provide a simple solution for deterministic source.
The idea• Use fs laser to excite a small volume of
atoms (<10 um)• Blockade limits excited atom number
Feedback system
• Use the electron position to actively correct the ion trajectory (ultimate aberration correction)
• Only possible to correct ions
Position sensitivedetector (DLD)
Feedback controlsystem
Ultimate source characterisation
• Would like to what is the coldest possible electron/ion temperature
• Accurate electron temperature measurement is difficult, gives little insight into heating mechanism(s) c.f origin of 10 K
• Ideally, want high resolution images of both electron k and x
• Electron microscope
• Photoemission electron microscope
Measurement of x/k
The PEEM
• PEEM provides high resolution (real space) imaging and (transverse) momentum imaging.
• Combined with TOF spectroscopy– Access to the longitudinal components
Can directly measure k and x
TOF PEEM
• Using a (3D) MOT as the sample, photoionisation dynamics can be investigated
Simulations
• With existing setup, we should be able to obtain high resolution images• Upfield emission directly resolvable!
Experiment planned Early 2014
LAC outlook• Short term:
– Source diagnostics– Single ion source
• Mid-term– TOF PEEM: Electron source characterisation– Nanofunctionalisation
• Long-term– Electron/ion feedback– HREELS
Outlook: other elements?• Cold atom electron/ion sources show a
lot of promise
• Cooling molecules can provide additional elements: e.g. CN, BaF …
CN for implanting diamond
No sources of: B, C, N, O, F, Si, Ga, Ge, As
Questions? Comments?
Thoughts?
Laser cooling = collimation Rydberg = excitation + Field ionisation
Improvefocus limit (10µm)x(∆E/E)
Huge domain of applications and improvement for: Spectrometers, irradiation, induced chemistry Imaging Sputtering, deposition
- +
IONIZATION OF COLD ATOMS or MOLECULESTo create Bright Ion/Electron beams
Example: Implantation of N atoms from Cooling of CN molecules