These curious items, about 4” (10 cms) long, and described as x-ray tubes, were acquired at eBay.   The  only information  given  by the seller reads: “I  came  across  these x-ray(?) tubes at a local flea market…..The gentleman I bought them from said they were needed for his work, and when no supplier could be located, the tubes were custom made with the assistance of a local glass blower and  a silversmith”.

In fact, I wonder whether these are x-ray tubes, although their structure is very similar to that of cold cathode x-ray tubes. A small molding on one end of the tubes reads “EGL”. So I searched the Internet, and found these initials belong to a company manufacturing neon lighting equipment, to whom I submitted the pictures. They  recognized the electrodes as being of their make, but, about X-Rays, they added the words: “NOT A NORMAL USE FOR THIS PRODUCT”.

The cylindrical electrodes are described as “nickel plated with a special internal emission coating” and the ceramic collar surrounding the cathode tip of the upper tube is “intended to eliminate side ignition, sputtering and blackening”.

I have no idea of the material of the anti-cathode targets, of the degree of vacuum or of the nature of the gas inside the glass tubing. In my opinion, if these tubes were really intended for some experimental x-ray work, they could not be used “in the air” with any sufficiently high kV to produce any usable radiation, and with any current exceeding a fraction of a mA. Anyway, the glass wall of the tubes doesn’t show the discoloration usually noted on tubes that have been in use.