MLZ is a cooperation between:

Technische Universität München> Technische Universität MünchenHelmholtz-Zentrum Hereon> Helmholtz-Zentrum Hereon
Forschungszentrum Jülich> Forschungszentrum Jülich

MLZ is a member of:

LENS> LENSERF-AISBL> ERF-AISBL

MLZ on social media:

Logo

MLZ (eng)

Lichtenbergstr.1
85748 Garching

Physics with Positrons TUM Research Group

  • The 2D-ACAR spectrometer built at MLL/TUM for the “Determination of Electronic Structure Using Positrons”, funded by TRR80/DFG.
    © W. Schürmann / TUM

  • The longer the positronium survives, the larger the pores are. Using this trick, the scientists could measure the pore sizes on a nm length scale.
    © Reiner Müller / FRM II, TUM

  • To avoid influences of the color, the scientists only examined red gummy bears using positrons.
    © W. Schürmann / TUM

  • User experiments at the CDB spectrometer at the positron source NEPOMUC.
    © W. Schürmann / TUM

  • Focusing unit of the positron beam inside the surface spectrometer at NEPOMUC.
    © Jakob Mayer / TUM

Our research encompasses the development of forefront instrumentation using positrons and the application of positron beams in a wide variety of fields ranging from fundamental physics via solid state and surface physics to applied materials science. By exploiting neutron capture gamma rays and subsequent pair production we generate the worlds most intense monoenergetic positron beam at NEPOMUC at the FRM II. The positron beam facility at NEPOMUC hosts various instruments (CDBS, TRHEPD, PAES, PLEPS, SPM, OP) open to external scientific users.

We apply (coincident) Doppler broadening spectroscopy of the annihilation photons to investigate open-volume lattice defects and precipitates. Our positron µ-beam at the CDB spectrometer allows 3D-imaging of defect distributions in all kind of materials. By using 22Na-based setups in the lab we apply positron annihilation lifetime spectroscopy (PALS) in order to study type and concentration of defects in crystalline solids as well as the free volume of polymers. The depth dependent positron lifetime is measured with PLEPS at NEPOMUC. Surface analysis with topmost layer sensitivity is performed via high-energy positron diffraction (structure) or by the detection of positron annihilation induced Auger electrons (element distribution). The bulk electronic structure is studied by the measurement of the angular correlation of the gamma radiation emitted from annihilation of electrons with (spin-polarized) positrons.

In collaboration with external groups we carry out fundamental experiments; examples are: determination of the decay rate of the Ps (Ps negative ion), velocity measurement of cold Ps, development of efficient e+-Ps converters for antihydrogen production, and setting up a magnetic trap for simultaneous storing of positrons end electrons aiming to produce the first pair-plasma.

Head of Research Group

Prof. Dr. Christoph Hugenschmidt
Phone: +49 (0)89 289-14609
E-Mail: christoph.hugenschmidt@frm2.tum.de


Physics with Positrons

> Home
> Team
> Research
> Publications & Presentations
> Teaching
> Photo Gallery
> Funding

MLZ is a cooperation between:

Technische Universität München> Technische Universität MünchenHelmholtz-Zentrum Hereon> Helmholtz-Zentrum Hereon
Forschungszentrum Jülich> Forschungszentrum Jülich

MLZ is a member of:

LENS> LENSERF-AISBL> ERF-AISBL

MLZ on social media: