After the Sun becomes a red giant, it will heat up its core to 100 million kelvins, which initiates the Triple-Alpha fusion process, which heats up the star's core even further and cause it to undergo a runaway thermal reaction, a helium flash.
However, I have not been able to find the final temperature of the core. Meaning that, although the star's core would heat up to 100 million kelvin, since the electron-degenerate core cannot expand, it just gets more hotter. I remember having read a paper where the Red giant's core would reach 1 billion kelvin, but I can no longer find that. What vague info I have in mind, is that the Red Giant's core would be between 100m-1b kelvins.
What would be the core temperature of the Red Giant Sun, after the Triple Alpha process causes it to heat up?