The Physician's Cap is an upgrade for the Cap of the Besieger, an item that can be purchased at the Trader Shop. It is a leveling item that goes from QL 15 to 75 and provides nice AC for its requirements. Best of all, it boosts Treatment, a bonus that is difficult to find for armor suitable for TL2 and TL3.
The Cap of the Besieger can be purchased from the Trader Shop. The Nano Programming Interface and Inactive OT Metamorphing Liquid Nanobots can be found in general shops. You can find the Notum Chip or Notum Fragment from mission mobs or regular Rubi-Ka mobs (any mob that drops gems). Try the Floaters and Bloaters in Foreman's for some easy Notum Chip harvesting above level 50.