Guys, X-Ray film is placed in contact with a screen the fluoresces when struck by X-Rays. Nuclear emulsions, sensitive to radiation, contain a substance to enhance their sensitivity to specific radiation. See Mees or Mees and James for this.
Chlorophyll is used by Mark Osterman at GEH. He uses Ivy, and extracts the dye getting a greenish solution. It does not keep its properties long.
Chris' list should serve us well, as should his suggestion.
I have not been able to get any information from my contacts, but some of the chemicals Chris suggests are available commercially.
There, that should answer most questions.