I really appreciate your detailed and insightful response, which taught me a lot about this (I am a PhD student major in optics, and know barely anything about circuits, so I am trying to catch up!). I totally agree with you that using a current source to drive the non-linear diodes can eliminate the variation of resistance due to the heating of these diodes over time.
I have some following questions with more details to really implement this circuit into my devices, as now we are more on common ground (I put on your diagram for reference here).
(1) More about R1 - the high impedance (~Gohm) R1 in this circuit is actually a capacitor with 0.1 nF before it is biased with 24V. When it is biased in a DC voltage circuit, there is a current of ~nA through this capacitor (there is some gas flowing through that forming such baseline current), and that is why I simplified it as a high-impedance resistor after it is biased in the circuit.
It seems to me that either R1 starts as a capacitor at the beginning, or a high-impedance resistor after biased, most of the current is going through the Zener diode D2, and therefore the purpose of maintaining the bias at 24V of R1 stands solid. Please confirm if I rationalize it correctly or not. I might be completely wrong here.
(2) Regarding D1, this is a home-made (inside a cleanroom) PN junction, I am attaching the I-V characteristics below
My purpose is to operate this diode beyond breakdown to achieve the avalanche process. Given the current driving circuit design, it seems to me that I can bias a constant current at 0.05 A (50 mA) such that D1 would operate near -60 V at reverse bias. Correspondingly, I should pick up a Zener diode D2, that has a test current with ~50 mA at 24V (P =1.2 W) for regulation with a power rating of 5W, see an example below -
Do you think this is a logical design? Please comment : )
(3) Final trivial question - what is the tool for drawing a diagram as you did? I know there are plenty of online tools, but I want to know what professionals use.
Looking forward to your responses!