TY  - JOUR
AB  - This beam was developed as a target for a crossed-beam electron-atom scattering experiment on the interaction of a polarized spin-1/2 electron with a polarized spin-1 atom. In the future this beam will be used in "Spin-Polarized Metastable Atom Deexcitation Spectroscopy" (SPMDS) for studying ferromagnetic surfaces without and with adsorbate layers. We use a discharge source for producing a beam of metastable helium atoms, a permanent sextupole magnet with a central stop at its exit for selecting He(2^3 S) atoms in the Zeeman substate ms=+1, a zero-field spin flipper for reversing the atomic beam polarization with respect to a magnetic guiding field, and a Stern-Gerlach magnet for analyzing the atomic polarization. At a distance of 90 cm beyond the exit of the sextupole, in the "interaction region" of an experiment, the polarized beam has a circular cross section of about 6 mm FWHM and a particle density of 1·10^7 atoms/cm^3. The reversible spin polarization was determined asP=0.90±0.02. A possible contamination of the beam with metastable singlet atoms is included within this value; the ground-state He atoms are not considered to be part of the polarized beam. An observed contamination with long-lived Rydberg atoms can easily be destroyed by applying a high electric field.
DA  - 1988
DO  - 10.1007/BF01384851
LA  - eng
IS  - 2-3
M2  - 171
PY  - 1988
SN  - 0178-7683
SP  - 171-178
T2  - Z.Phys. D
TI  - Production of a spin-polarized, metastable He(23 S) beam for studies in atomic and surface physics
UR  - https://nbn-resolving.org/urn:nbn:de:0070-pub-17768238
Y2  - 2024-11-22T12:54:07
ER  -