LAPPD Figures for Papers and Talks

Img 0691


Populated analog card with tile.



The initial PSEC4 application: a high-channel density waveform digitization of a large-area MCP RF microstrip anode.

Strip map v3


The geometry
of the test setup: A signal is input on the near end of the central
strip (shown in red) and is detected at the far end. The power is
measured on the near and far ends of the neighboring strips.}

Comparison 30 30 3 40 cross talk v2


Comparison of total normalized power summed over all
strip-lines for three different anode geometries: a single 30-strip
tile (triangles), a single 40-strip tile (circles), and three
30-strip tiles in series.



{The mechanism of cross-talk for a positive signal with a
linear rising edge~\cite{Bogatin}. Two adjacent strip-lines are shown;
the common ground plane is not shown for clarity. The active line is
driven on the near end with a signal pulse of rise-time $t_r$. At the
far end of the active line the same pulse is seen a time $t_d$ later,
determined by the length and characteristic velocity of the line. The
neighboring line, the quiet line, is coupled to the active line
capacitively and inductively by the electric and magnetic fields,
respectively. At the near end of the quiet line a positive voltage
appears at the start of the signal and persists for 2$t_d$. For an
inductive coupling, at the far end a negative voltage appears starting
at $t_d$ with a width~$t_r$.

Bandwidth 3db all log v4


The bandwidth measured at 3db loss on the central strip
versus the log of the total anode length. The anodes consisted of 3 and 4
tiles in series (746.7 mm and 916 mm, respectively, including the
length of the fanout card strips), a single tile
(288.5 mm), and only the 2 fanout PC cards connected to each other
(`zero tiles'- 59.4 mm).

Comparison 30 40 0 vs freq v2


The normalized power (output power/input power) versus
log-frequency for a single 229.1 mm-tile plus fanout cards(288.5 mm)
with 30 strips (red, middle trace), 40 strips (blue, bottom trace),
and the fanout PC cards alone(`zero-tile', in green, top trace). See
Figure~\ref{fig:single_tile}. The (black) horizontal line
represents the 3db loss level (50\% loss in power).

Impedance plot v3


The measured real (top) and imaginary (bottom) impedance
versus frequency for 40-strip and 30-strip silk-screened anodes on a
single 229.1 mm-long glass tile base between two fanout cards.
The targeted design impedance (top) was 50\ohm.

All w reference v4


The anode responses in the time domain to a step-function
introduced into one end of a strip in a multi-strip anode. The
source of the reference pulse is the calibration output from a
Tektronix TDS6154C oscilloscope, which has a risetime of 200 psec
and an amplitude of 440 mV (peak-peak). The response curves in
the figure were measured with the same oscilloscope.



The geometry of the coupling between the coaxial cable
from the pulse generator to the anode strip after impedance matching with copper tape