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TDR Measurement of MCP Anode. Camden Ertley. Index. TDR Setup Method Results 16 pixels tied together 9 pixels tied together 4 pixels tied together 1 pixel Conclusion. TDR Setup.
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TDR Measurement of MCP Anode Camden Ertley
Index • TDR Setup • Method • Results • 16 pixels tied together • 9 pixels tied together • 4 pixels tied together • 1 pixel • Conclusion
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 Channel 1 Input Fast Edge -0.14 to +3V 1kHz MCP Output Fast Edge from Scope 100mV and 500ps per div
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.
16 Pixels Tied Together • TDR • Assuming infinitely fast rise time pulse used. • Fall time: 329.1 ps • C = 6.582 pF • Actual rise time of pulse used subtracted from measured. • Fall time: 141.1 ps • C = 2.822 pF • LCR meter. • Measured = 55.62 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
9 Pixels Tied Together • TDR • Assuming infinitely fast rise time pulse used. • Fall time: 304.1 ps • C = 6.082 pF • Actual rise time of pulse used subtracted from measured.. • Fall time: 116.1 ps • C = 2.322 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
4 Pixels Tied Together • TDR • Assuming infinitely fast rise time pulse used. • Fall time: 260.8 ps • C = 5.216 pF • Actual rise time of pulse used subtracted from measured. • Fall time: 72.8 ps • C = 1.456 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
1 Pixel • TDR • Assuming infinitely fast rise time pulse used. • Fall time: 249.2 ps • C = 4.984 pF • Actual rise time of pulse used subtracted from measured. • Fall time: 61.2 ps • C = 1.224 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
Conclusion • LCR meter • 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.