Tuesday, December 13, 2011

Precision spectroscopy in helium (Amsterdam, The Netherlands)

In the physics of light and matter group of the VU university in Amsterdam chair prof. dr. W.M.G. Ubachs) we have two openings for PhD research.

Position 1: Ultracold Helium atoms.
Goal is to accurately measure transition frequencies in helium atoms, laser cooled and trapped in a long-lived metastable state, at a temperature of 1 microKelvin in an optical dipole trap, see our paper in Science, 196 (2011) for a first result. This work aims to improve experimental tests of QED theory of atomic structure, to deduce the nuclear charge radius of the alpha-particle and the helion (the helium-3 nucleus) and to measure the fine structure constant. PI: dr. Wim Vassen

Position 2: Frequency comb spectroscopy.
This project also aims to test QED in helium atoms and ions. In this case excitation is from the ground state of helium and from the ground state of the helium-ion. This requires a frequency comb in the extreme ultraviolet part of the spectrum, which is generated by pulsed amplification and frequency upconversion of a femtosecond frequency comb laser, see PRL 063001 (2010). Excitation of helium atoms will be in a collimated beam, while the helium ion will be excited in an ion trap. PI: prof. dr. Kjeld Eikema Both projects rely on ultrastable lasers to excite atomic transitions and frequency metrology using a femtosecond frequency comb laser, locked to an atomic clock. Both PhD students will also work to build frequency stabilized lasers at the Hz-level.

We are looking for highly motivated students with interest in experimental atomic, molecular and optical physics, preferably with experience in either laser cooling and trapping, cold molecules,atomic and molecular spectroscopy, or related topics. A Diplom (MSc) degree in Physics, Applied Physics or another relevant field is a prerequisite. The positions are standard Dutch 4-year PhD positions, with full salary (up to a maximum of 2,610 euro gross per month).

Applicants should send their CV along with a motivation letter. The positions are immediately available, but the latest starting date is April 2012. Therefore students who will complete their Diplom (MSc) in the coming months are also welcome to apply.

* Wim Vassen
* LaserLaB VU university
* De Boelelaan 1081
* 1081 HV Amsterdam
* E-Mail: w.vassen@vu.nl
* Telephone: +31 20 5987949
* Website: http://www.nat.vu.nl/en/research/physics-light/fundamental-physics-at-the-atomic-scale/

Post-Doc and PhD positions in TEM

The Institute for Experimental Physics at the University of Ulm invites applications for

2 Post-Doctoral (100 %) and 2 PhD student positions (50 %)

starting at the earliest possible date. The PhD positions will be for 3 years and the PostDoc positions for initially 2 years. Salary is according to German standards E13 TV-L.

The positions are available in the area of theoretical and experimental transmission electron microscopy. Possible topics include: a) 3D Strain mapping in semiconductor devices with sub-nanometer spatial resolution, b) Quantitative inline holography, c) Quantitative 3D electron diffraction and crystallography, d) Development of numerical tools to solve the dynamic inversion problem in electron diffraction from LARBED data, and e) Development of new electron optical devices.

The successful applicant will join the group of Prof. Christoph Koch (a recently established Carl Zeiss Professorship) at Ulm University. The experimental work will be carried out in a well-equipped TEM laboratory featuring, among others, a unique 200 kV Zeiss EM922 TEM featuring a high-transmissivity corrected Omega-type in-column filter, an imaging aberration-corrected FEI Titan 80-300, and, in the near future, the Cs-Cc-corrected Zeiss SALVE microscope optimized for atomic resolution at accelerating voltages between 20 and 80 kV. A modern specimen preparation lab including also a triple-beam FIB is available as well.

Applicants should have either a masters (for the PhD positions) or a doctorate (for the post-doc positions) degree in physics, mathematics or materials science and should be skilled in at least one computer programming language (preferably C/C++, Matlab, or Python). Knowledge of (electron) optics, diffraction, and (dynamical) electron scattering theory, as well as hands-on (experimental) TEM experience would be an advantage.

Informal inquiries can be made to christoph.koch@uni-ulm.de.

The university of Ulm is committed to increase the share of women in research and teaching positions and therefore explicitly encourages female candidates to apply.

The deadline for application is 22 December 2011 (or until positions filled). Applications should be sent to Prof. Christoph Koch, Institut für Experimentelle Physik, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany and should include CV, list of publications, research interests, and names of two referees. Please indicate on the envelope the index number 132.

Job sharing is always possible for full time positions. Physically disabled applicants receive favourable consideration when equally qualified. The appointment is made by the central university administration.