A very important performance parameter
for electron multipliers is the temporal or time response of
the detector. The detection time is essentially proportional
to the aspect ratio - the thickness - of the Microchannel Plate
(MCP). Since these devices have very short path lengths, they
tend to have very short response times. And the high internal
electric field within the channel guarantees that the electron
multiplication process happens very quickly.
Typical results from this type
of a design are that the transit time of the pulse within a
channel is very short, typically one nanosecond. Pulse spreading
is minimized, resulting in narrow pulse widths of less than
one nanosecond.
Microchannel plates are used in
a number of very time-dependent applications. Figure 1 shows
some typical results of a small pore microchannel plate and
the resultant temporal response after having stimulated the
detector with a single ion event. The amount of propagation
time (amplification time) can then be measured and recorded
using a high speed digital oscilloscope. In Figure 1, a 0.51
nanosecond pulse width and 0.34 nanosecond rise time were achieved
with a 25mm format matched set of 5µm pore microchannel plates.
Matched Anode