| 摘要 |
A High Frequency light source (11) has a central body (12) of fused quartz, with a central void (14), filled with a fill (16) in the void of material excitable by High Frequency energy to form a light emitting plasma. An inner sleeve (17) of perforate metal shim extends along the length of the central body to within 2.5 mm of its void end to provide a launching gap (18). The sleeve has a transverse end portion (19) extending across the other, inner end of the central body. An outer cylinder of fused quartz (20) with an internal bore (21) such as to be a sliding fit with the inner sleeve, itself a sliding fit on the central body. An outer sleeve (22) of perforate metal, enclosing the outer cylinder and having an end portion (23) extending across the flush, void ends of the quartz body and cylinder (12,20). The outer sleeve has a skirt (25) extending past the flush other ends of the quartz elements over an aluminium carrier (26), where it is clamped, holding the quartz elements against the carrier. Thus the sleeve forms with, with its end (23) and the carrier (26), a Faraday cage around the quartz and the plasma void (14). An antenna (27) insulated from the carrier extends from it into a bore (28) in the quartz cylinder (20) for introducing HF radiation into the coaxial wave guide formed by the inner and outer sleeves (17,22). Their perforation is such as to make them opaque and enclosing to the HF radiation yet light transmissive, whereby light from the plasma can pass through them. The portion of the antenna in the carrier provides a connection to an non-shown source of HF energy. The inner sleeve (17), at its end portion (19), is earthed to the carrier, in the same way as the outer sleeve and its end portion (23). Thus the gap (18) between the end of the inner sleeve and the end portion of the Faraday cage forms a launching gap for the HF energy to radiate to the plasma void and establish and maintain the plasma there. Light from the plasma passes through the quartz and through the perforations in the sleeves and the end portion (19), thus out of the light source. |
