Wellhöfer
Waterproof Farmer-Type Ionization Chamber
The FC series are ionization chambers of a classic Farmer design, intended for absolute dosimetry, that meet or exceed performance standards of the original Farmer design. Similarities to the original Farmer include conformity to all external physical dimensions, a choice of thimble materials (graphite or robust), sensitive volumes of 0.65cm3 and 0.23cm3, and atmospheric communication. Additional features not shared with the original Farmer include guarding up to the measuring volume and waterproof construction.
The low-noise 3.3mm diameter triaxial cable is sheathed along the entire 1.5m length and terminated with a male triax BNC connector with dust cap & chain (TNC connector is optional). Each chamber includes a Delrin 60Co buildup cap, a padded storage case and QA checkout at CNMC.
Model FC65-G
Graphite thimble, aluminum electrode - The Model FC65-G is a direct replacement for the NE 2571A. It features a thin-walled graphite thimble, an aluminum center electrode and a sensitive volume of 0.65cm3.
Model FC65-P
Delrin thimble, aluminum electrode - The Model FC65-P most closely resembles the NE 2581A, in that it has a rugged thimble made of Delrin (POM, poly-oxy-methylate), an aluminum center electrode and a sensitive volume of 0.65cm3.
Model FC23-C
AE Thimble and electrode - The Model FC23-C offers improved spatial resolution for greater precision in the measurements of beam profiles and isodose contours. It most closely resembles the NE 2577C but features a conductive C552 air equivalent thimble, C552 center electrode and a volume of 0.23cm3.