[yt-users] How to make a projection plot of a desirable thickness?

Hi, I would like to make a projection of a field along 'z' axis centered at [0.5, 0.5, 0.5] with a thickness of 10Mpc (5 Mpc to +z dir and 5 Mpc to -z dir). How to select the above-mentioned region from the whole simulation volume? I am using YT Legacy 2.x. Thank you. -- Reju Sam John