I am a little bit puzzled with regards to your jackpot. I was puzzled about the formula, f is the minimum bet amount which is a little bit understandable.
But what I want to know is whether the Jackpot is available to anyone? or it has a certain rules to be able to participate in it like the minimum bet that
are present in the formula.
AFAIK there is no minimum bet requirement for the jackpot, means that you can win it with any bet amount.
You'll always get a percentage from the jackpot based on your bet amount.
The smaller your bet amount, the smaller percentage you'll get from the jackpot and vice versa.
Just take a look at the jackpot winner history, there are some examples of jackpot hit with small bet in ETH and BTC.