The 6097B is a cold cathode photomultiplier. The data-sheet shows that it was used by the UK Atomic Energy Authority. The base is the special EMI 15 pin type.
The multiplier has a photocathode inside the end window and 11 stages of secondary emission amplification before the anode. The peak sensitivity is in the blue end of the visible spectrum. The sensitivity is rated at 200 Amps per Lumen.
The photocathode on the inside of the end window and behind are the plates of the first dynode for secondary emission of electrons.
The special EMI 15 pin base.
The dynode stack, each held at a greater positive potential than the one before.
The dynodes seem to be made of a mesh within an outer frame.
The end window envelope is 51 mm in diameter, and excluding the base pins is 110 mm tall.