I'm trying to model the Laser Components SAP500-T8 SPAD in multisim by modifying the BYW54 model available in multisim. Unfortunately I really don't know how to go about it.
The circuit in question is taken from the article "S. Tisa∗, F. Zappa, A. Tosi, S. Cova. Electronics for single photon avalanche diode arrays//Elsevier._-2007-Sensors and Actuators A 140 - Sensors and Actuators A 140"

 

Multisim working and user settings to correct convergence error for Calmon/Macintyre 2021
Rload might be ok. The dead space is clear but using 1N829 R1= 2.33K and changing 1n to 100p
when the electric field is in range then those other artifacts in higher resolution show for tuning.



Francis Calmon An analytical solution for McIntyre's model of avalanche triggering probability for SPAD compact modeling and performance exploration