Tübingen 2003 – wissenschaftliches Programm
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HK: Physik der Hadronen und Kerne
HK 18: Instrumentation und Anwendungen II
HK 18.14: Vortrag
Dienstag, 18. März 2003, 18:45–19:00, C
A High Brightness Source for Polarized and Unpolarized Negative Hydrogen Beams — •Ralf Hertenberger1, Yvonne Eisermann1, Hans-Friedrich Wirth1, Gerhard Graw1, Günther Dollinger2, and Patrick Reichart2 — 1Sektion Physik, LMU München — 2Physik Department E12, TU München
The polarized hydrogen ion source of the Munich tandem laboratory
consists of a Stern-Gerlach atomic beam source
followed by an electron cyclotron resonance ionizer
and a cesium jet target for charge exchange.
Accelerated H and D ion beams with intensities
of up to 3 µA and with polarization
above 70 % have been observed on target.
Of present interest is the use
as an injector of dense unpolarized H− ion beams,
as they are needed for the nuclear nanoprobe SNAKE.
A superconducting quadrupole doublet
with short focus length is used to focus
ion beams to sub-micrometer spotsize
for materials investigation or
for irradiation of biological samples.
In unpolarized mode the source provides
negative hydrogen beams of 50 µA DC within
the nominal acceptance of the tandem accelerator.
A system of beam formation slits in the object position of the
superconducting quadrupole doublet defines the
diameter and the divergence of the 17 MeV beam
to x*y=30*100 µm2 and
(0.13 mrad)2.
The beam intensity of 80 pA on target is
equivalent to a brilliance of
90 nA/mm2 mrad2 MeV.
Hydrogen analysis by pp-scattering
with submicrometer resolution
and ppm sensitivity becomes possible.
A clear hydrogen enrichment
on grain boundaries
in CVD-grown diamond has been observed.
Work supported by the DFG under C4-Gr894/2-3 and by the MLL.