EMISSION SPECTRUM OF TRITIATED ACETYLENE

Abstract

The spectrum of visible emission from tritiated acetylene gas in closed cell with no external excitation has been recorded. Two forms of gas were used: (1) $C_{2}HT$, synthesized by a modified Wilzbach process and mixed with $C_{2}H_{2}$: (2) mixtures of $C_{2}H_{2}$ and $T_{2}$. The gases were held in stainless steel cells of about $20 cm^{3}$ volume with sapphire windows. Pressures were 100-300 Torr. Emitted photons were analyzed with a 1/2-m monochromator, an RCA 31034A-12 photomultiplier, and standard counting electronics. The spectra exhibit the well-known Swan bands of $C_{2}$ and a broad band which may be $C_{2}H$. The CH 431.5 nm band was not prominent. The emission results entirely from the radioactivity of the gas. The energy of the fast beta produced in the tritium decay $T_{+}^{3}He^{+} + \beta^{-} +\upsilon^{-}$ is collisionally degraded in a variety of secondary processes. The observed spectrum can be understood only by examination of the complete degradation energy spectrum.