  We report on the design and characterization of an antiproton deceleration
beamline, based on a pulsed drift tube, for the PUMA experiment at the
Antimatter Factory at CERN. The design has been tailored to high-voltage (100
kV) and ultra-high vacuum (below $10^{-10}$ mbar) conditions. A first operation
achieved decelerating antiprotons from an initial energy of 100 keV down to
($3898\pm 3$) eV, marking the initial stage in trapping antiprotons for the
PUMA experiment. Employing a high-voltage ramping scheme, the pressure remains
below $2\cdot 10^{-10}$ mbar upstream of the pulsed drift tube for 75% of the
cycle time. The beamline reached a transmission of ($55 \pm 3$)% for
antiprotons decelerated to 4 keV. The beam is focused on a position sensitive
detector to a spot with horizontal and vertical standard deviations of
${\sigma}_\mathrm{horiz}$ = ($3.0 \pm 0.1$) mm and ${\sigma}_\mathrm{vert}$ =
($3.8 \pm 0.2$) mm, respectively. This spot size is within the acceptance of
the PUMA Penning trap.
