Photo: National Institute of Standards and Technology
In 1940, the U.S. National Bureau of Standards (NBS) built this 1,400,000-volt X-ray generator, the most powerful of its kind at the time. The machine was designed to deliver X-rays at an extremely stable voltage, a necessary attribute for the development of standard radiation dosage measurements as well as for research and testing of equipment to protect against X-ray radiation.
While X-rays were known to be dangerous much earlier than 1940, there wasn’t a good understanding of exactly how much exposure was bad for humans, or what kinds of materials offered effective amounts of protection. At the time, for example, concrete was commonly used to absorb and scatter X-rays, but nobody knew exactly how well it worked. Testing at NBS revealed that concrete responded differently depending on if the radiation was narrow beam or broad beam, and the results helped establish guidelines on radiation-resistant construction. The agency also established the first U.S. standards for X-ray exposure; the chalkboard in the 1959 photo above shows calculated tissue doses for safe radiation exposure.
The man at the chalkboard is Lauriston S. Taylor, chief of the NBS X-ray section. Taylor, who was born in 1902, became interested in X-rays as a boy, after Thomas Edison gave him a cold-cathode X-ray tube during a school trip to Edison’s lab. After dropping out of college because he couldn’t afford tuition, Taylor spent a year at Bell Telephone Laboratories and later finished his doctorate at Cornell, where he studied electronics and radiology. A one-year position studying the effects of X-rays at the National Bureau of Standards turned into 28 years working on radiation dosimetry and radiation protection. By 1951, Taylor was chief of the atomic and radiation physics division at NBS, which became the National Institute of Standards and Technology in 1988.
Because Taylor was one of only a few radiological physicists working on defining what amounts of radiation were harmful to humans, the lab he worked in at NBS wasn’t always the safest, especially early on. In a 1995 interview, Taylor recalled one such episode:
“The only single documented whole body exposure that I know that I’ve had was in 1929, and it was measured to be 150 [Roentgen]…. I sat in an X-ray beam for 20 minutes or half an hour or something…. I was just sitting right smack in the beam…. [With that much radiation] you’re supposed to get nauseated, but we didn’t know that in 1929, so I wasn’t.”
For the record, 150 Roentgen is equivalent to 1.4 sievert, which according to this chart starts to put you in the realm of “severe radiation poisoning, in some cases fatal.” But since the chart wasn’t around in 1929, Taylor was just fine. Indeed, he told the interviewer in 1995, “I also used to treat [my] athlete’s foot.... I don’t remember what the dose was, but it was probably four or five hundred R [3.7 to 4.7 Sv].”
“That exposure in addition to medical radiation treatment for bursitis and other benign conditions and from radiation experiments resulted in an estimated whole-body dose-equivalent in excess of a thousand rem [10 Sv],” Taylor’s obituary for the Health Physics Society stated. “He experienced no discernible adverse effect.”
Taylor continued working until the age of 97, and having published over 160 scientific papers and writing or contributing to 24 books, he died in 2004 at the age of 102.
A shorter version of this article appeared in the May 2017 print magazine as “Dr. Taylor’s X-ray Machine.”
Part of a continuing series looking at old photographs that embrace the boundless potential of technology, with unintentionally hilarious effect.