XCON/XCIO: Absorbers and Converters description
XCON and XCIO are motorised supports that allow to move
absorbers and converters into or out of the beam line.
| XCON: |
Have a step motor that
allows precise positioning over
a 200 mm range. The frame
mounted on this support may
contain e.g. lead sheets of
varying thickness. This provides
the user with a choice of
various absorber or converter
thicknesses. |
| XCIO: |
Have only an In/Out
movement. These devices allow to
move a converter or absorber
into or out of the beam. See the
picture below. |
An absorber is a piece of material (normally a few mm
Lead) that is brought on the beam passage to stop remaining
electrons in the beam. As the electrons loose energy in the
material due to Bremsstrahlung, they will not be transported all
the way down to the experiment and they are thus lost from the
beam.
A converter is a piece of material (normally a few mm
Lead) that is situated after a production target and a sweeping
magnet. The magnet removes all charged particles from the beam
line and the photons remaining convert in the converter into e+e-
pairs. The electrons (positrons) are picked up by the beam
transport and are delivered to the experiment as if they were
produced directly in the production target. This technique may
lead to very clean electron beams.
The converter shown on the picture above is a 1 mm thick
Copper sheet that converts photons into electrons for a tagged
photon beam.
more information about
XCON converter and
XCIO in-out converter |
