  Beam diagnostics are crucial for smooth accelerator operations. Many
techniques rely on instrumentation in which the beam properties are
significantly affected by the measurement. Novel approaches aim to use
Cherenkov Diffraction Radiation (ChDR) for non-invasive diagnostics. Unlike
regular Cherenkov Radiation, the charged particles do not have to move inside
of the medium, but it is sufficient for them to move in its vicinity as long as
they are faster than the speed of light in the medium. Changes to the beam
properties due to ChDR measurements are consequently negligible. To examine
ChDR emission under different conditions, we placed a fused silica radiator in
the DESY II Test Beam. We observed a linear increase in ChDR intensity for
electron and positron momenta between 1 GeV/c and 5 GeV/c. Additionally, we
found that electrons produce significantly more ChDR than positrons for
increasing particle momenta. The results suggest a need for further research
into the ChDR generation by electrons and positrons and may find application in
the design of future beam diagnostic devices.
