Benzothiazole-containing tetrazolium salts as radiochromic indicators in gel dosimetry

Benzothiazole-containing tetrazolium salts (Bt-TS) have been previously described but have never been tested for dosimetry applications. Considering that such salts may provide higher dose sensitivity than previously tested tetrazolium salts, we synthesized a library of Bt-TS, three of which are reported here. Dosimeters based on the salts BtPP, BtNP and BtNpP were prepared in gellan gum gels, and compared to a previously-described gel dosimeter, based on bisnitrotetrazolium chloride (BNC) in the same medium. All three Bt-TS showed a higher sensitivity at their respective wavelengths of maximum optical attenuation post-irradiation. Two of the new Bt-TS (BtNP and BtNpP) were identified for further studies in large-scale samples and other gel-forming materials.