194 



BIOLOGICAL EFFECTS OF RADIATION 



2000 4000 6000 8000 lOOOO 12000^ 



WAVE LENGTH 



Fig. 31. — Relative-sensitivity curves of commercial photocells (in each case the area in 



sq. in. and the name of the manufacturer are given within parentheses): 1. PJ-22 vacuum 



(0.9, Gen. Elec.); lA. PJ-23 gas-filled (0.9, Gen. Elec); 2. Visitron type AV, quartz envelope, 



vacuum (1.1, G. M.); 2A. Visitron type A, quartz envelope, gas-filled (1.1, G. M.); 



3. Western Electric, vacuum {Western El.); 3 A. Western Electric, gas-filled {Western El.); 



4. FJ-114 (0.9,Gen. .E/.),-5. FJ-76 (2.1, Gen. jEL); 6. Weston Photronic cell (1.7 TFesion M.). 



