| 摘要 |
<p>A photoionization detector for a gaschromatographic apparatus comprises an ionization chamber (4) provided with a polarizing electrode (5, 5') and a collector electrode (6, 6'), mounted on and heated by a base portion of the detector, and a lamp (2) with a window (3) spaced from the chamber (4) and mounted on the base portion through supporting means (12) having low thermal conductivity; a gas curtain of a gas that is transparent to the said lamp radiation being provided at least between the window and the ionization chamber (4) and comprising a first portion (A) of substantially still gas acting as thermal insulant and a second portion (B) of flowing gas also acting as sweep gas for the lamp window (3).</p> |
