1. TDR Measurement of MCP Anode
Camden Ertley

2. Index TDR Setup Method Results Conclusion 16 pixels tied together

3. Fast Edge from Scope 100mV and 500ps per div
TDR Setup
The fast edge, ~280ps rise time, produced by the scope was used. The signal was split with a SMA T. One T output was connected to the Ch 1 input the other went to the MCP. The cables used were 2.5ns rg58 coax with SMA ends.
Scope
Fast Edge
-0.14 to +3V 1kHz
Channel 1
Input
MCP Output
Fast Edge from Scope 100mV and 500ps per div

4. Method TDR: Connected in manner shown on setup slide
Measured pulse height and fall time for each number of pixels
Calculated C using 67% of fall time (one time constant). Assumed to be single pole.

5. 16 Pixels Tied Together TDR MCP Pulse 50mV and 500ps per div
Assuming infinitely fast rise time pulse used.
Fall time: ps
C = pF
Actual rise time of pulse used subtracted from measured.
Fall time: ps
C = pF
LCR meter.
Measured = pF
Cable = 50.3 pF
C = 5.32 pF
MCP Pulse
Rise Time
480 ps
Amplitude
144.8 mV
50mV and 500ps per div
20mV and 500ps per div

6. 9 Pixels Tied Together TDR MCP Pulse 50mV and 500ps per div
Assuming infinitely fast rise time pulse used.
Fall time: ps
C = pF
Actual rise time of pulse used subtracted from measured..
Fall time: ps
C = pF
LCR meter.
Measured = 53.8 pF
Cable = 50.3 pF
C = 3.5 pF
MCP Pulse
Rise Time
478.0 ps
Amplitude
117.8 mV
50mV and 500ps per div
20mV and 500ps per div

7. 4 Pixels Tied Together TDR MCP Pulse 50mV and 500ps per div
Assuming infinitely fast rise time pulse used.
Fall time: ps
C = pF
Actual rise time of pulse used subtracted from measured.
Fall time: 72.8 ps
C = pF
LCR meter.
Measured = 51.8 pF
Cable = 50.3 pF
C = 1.5 pF
MCP Pulse
Rise Time
477.4 ps
Amplitude
79.88 mV
50mV and 500ps per div
20mV and 500ps per div

8. 1 Pixel TDR MCP Pulse 50mV and 500ps per div 20mV and 500ps per div
Assuming infinitely fast rise time pulse used.
Fall time: ps
C = pF
Actual rise time of pulse used subtracted from measured.
Fall time: 61.2 ps
C = pF
LCR meter.
Measured = 53 pF
Cable = 50.3 pF
C = 2.7 pF
MCP Pulse
Rise Time
420.4 ps
Amplitude
59.46 mV
50mV and 500ps per div
20mV and 500ps per div

9. Conclusion LCR meter TDR
Different cables were used on each measurement (we didn’t want to remove and reattach them)
TDR
Seems to show a contribution of ~0.1 pF for each pixel added.