UBC Theses and Dissertations
An 8mm solid state spectometer Lee, Ker Ping
A sensitive, wide or narrow band, solid state spectrometer operating at a wavelength of 0.85 cm has been built which is described in detail. The spectrometer is of the crystal detector reflection-cavity-in-magic-Tee-bridge type and can operate from room down to liquid helium temperatures. The cavity Is excited In the TE₁₁₁ mode and the magnetic field modulated at 140 cps. Both large and small field modulations are incorporated for scope presentation of line width varying from about 0.5 to 500 gauss. Signals from single crystals of copper sulphate pentahydrate and polycrystalline 1-1-diphenyl-2-picryl hydrazyl (DPPH) have been obtained. From the latter, a sensitivity limit of about 10⁻⁸ gram is obtained at room temperature for a bandwidth of 1 cps indicating a sensitivity of the order of 10⁻¹¹ gram at 4.2° K. Various methods of improvement were discussed in order to reach the ultimate sensitivity.
Item Citations and Data