Single Wall Carbon Nanotube Response to Proton Radiation

In the interest of developing a highly sensitive, low power radiation dosimeter, a series of tests were performed on single-wall carbon nanotube (SWCNT)-based nanomaterials to monitor their response to 10 and 30 MeV proton radiation. The SWCNT materials were deposited on an interdigitated electrode (IDE) that was developed at NASA Ames for chemical sensing. In order to investigate the effects of nanotube functionalization on the sensor properties, the SWCNTs were covalently or noncovalently functionalized prior to their incorporation into the devices. The functionalized nanotubes which were assayed included fluorinated SWCNT (F-SWCNT), alkylated F-SWCNT (F-SWCNT-C(11)H(23)) refluorinated alkylated F-SWCNT (F-SWCNT-C(11)F(23)), palladium doped SWCNTs (Pd-SWCNTs), and nanotubes noncovalently associated with cellulose (Cel-SWCNTs). These five functionalized nanotube types and pristine carbon nanotubes were investigated for their responses to proton radiation. The device response to irradiation, measured as a change in resistance, was found to vary with the type of functional group attached to the SWCNT. The samples were also characterized by Raman spectroscopy in order to observe changes in the disorder band (at 1350 cm(-1)) of the nanotube materials. Depending on nanotube functionalization, the devices showed a real-time response to radiation at the energy levels tested. The nature of the response indicates that these nanomaterials may potentially be used to produce a dosimeter that is memory-free, reusable, and reversible.