<DOC>
<DOCNO>
1316
</DOCNO>
<TITLE>
temperature measurements of shock-waves by spectrum-line reversal, ii a
double beam method .
</TITLE>
<AUTHOR>
clouston, j.g., gaydon, a.g. and hurle, i.r
</AUTHOR>
<BIBLIO>
proc. roy. soc. a252, p143, september 1959 .
</BIBLIO>
<TEXT>
the sodium-line reversal method, as previously described, using a
photomultiplier and oscillograph, has been modified . two light beams
are now employed, and interference filters are used in front of the
photomultipliers instead of a spectrograph . in one beam the background
source is viewed directly, through the shock tube, and in the other beam
 the background source is viewed through the shock tube by a mirror
system with a neutral filter interposed to reduce its effective brightness
temperature . with a suitably chosen temperature for the background,
one oscillograph trace indicates absorption and the other indicates
emission of the sodium lines . it is thus possible, from the
records of a single shock, to determine the temperature history behind
the shock wave to about 20degreec . nitrogen and oxygen again show relaxation
effects near the front . temperatures in argon tend to come
low, owing to radiative disequilibrium,. excitation processes in argon
are discussed . with this system it is possible to determine temperatures
rather higher than that of the background source . some work has
also been done, with a single-beam method, using a carbon arc as
background and following reversal of the indium blue line . temperatures
 up to 3600degreek have been measured in shocks through nitrogen, but
the time resolution is not so good .
</TEXT>
</DOC>
