A few days ago,I made a very simple 5V-170V boost circuit just for lighting up my QS30-1 nixie tubes.And as you all can see in the picture,it worked really well.
By using this simple circuit you can get the max output up to 300V DC from a 5V supply.This circuit is still in testing,and will be improved in the next month.And I believe this circuit will definitely be helpful for my future nixie design.