Chemistry Reference
In-Depth Information
to a fast long-range diffusion of Fe in Pb (Fig.
6.20
c), but the effect was appeared
to be too small to discuss into more details.
At the Hahn-Meitner Institute, in addition to the experiment on Fe in Si [
26
], as
mentioned in the
Sect. 6.2
, Fe in alkaline metals was also studied using the same
technique [
33
,
34
].
6.4 On-line
57
Mn/
57
Fe Implantation Mössbauer Spectroscopy
at ISOLDE, CERN
The ISOLDE facility is a world-leading laboratory for the production and study of
shortlived radioactive nuclei. ISOLDE belongs to CERN's accelerator complex
situated on the border between Switzerland and France. The ISOLDE facility has
been in operation since its start in 1967.
The radioactive nuclei are produced in reactions of high-energy protons from
the PS-Booster accelerator in thick targets. The typical proton energies are
between 1 and 1.4 GeV. More than 25 different target materials are used. The
target material is kept at an elevated temperature so that the produced radio-
active atoms diffuse out of the target into different dedicated ion sources. Ion-
isation can take place in a hot plasma, on a hot surface or by laser excitation. By
judicious combinations of target-ions sources a chemical selectivity may be
obtained and has resulted in selective production of more than 70 of the
chemical elements. The ions are swept out of the ion-source by an applied
voltage, accelerated to 30-60 kV and directed into an electro-magnet where they
are separated according to their mass. In this way ISOLDE has been able to
deliver more than 700 isotopically pure beams with intensities ranging from 1 to
more than 10
10
ions/s.
The main lines of research at ISOLDE are: nuclear structure physics, nuclear
astrophysics, atomic physics, solid state physics, life sciences and fundamental
interactions. A laboratory portrait been published as a special volume of Hyperfine
Interactions [
35
]. In this volume a complete chapter is devoted to ''Mössbauer
Spectroscopy at ISOLDE'' [
36
]. A schematic view of the set-up is shown in
Fig.
6.22
.
6.4.1 Site Selective Doping of III-V Semiconductors
The
119
Sn Mössbauer isotope can be studied in off-line emission Mössbauer
experiments starting from the longlived
119m
Sn isomeric parent. The ISOLDE
facility offers the interesting possibility to access the Mössbauer transition from
the shortlived radioactive
119
In (T
1/2
= 2,3 min) and
119
Sb (T
1/2
= 38 h) precur-
sor parents.
