Blewett Had Help With GE Synchrotron

Ernest Courant’s obituary of John Paul Blewett (Physics Today, February 2001, page 76 ) erroneously credits Blewett with initiating the project at the General Electric Research Laboratory to construct a 70-MeV synchrotron. As I recall after over a half-century, Blewett’s work while he was at GE was mainly with radar equipment, although he was an interested observer of the accelerator work and did help with the synchrotron orbit calculations. The project was initiated and directed by Herbert C. Pollock, who, with that accelerator, first actually observed “white” synchrotron radiation and measured its spectrum. ^1,2 The choice of 70 MeV was based on the availability of a suitable magnet, one that had been developed by Willem Westendorp for a 50-MeV biased betatron.

As an active witness of those events, I provided the data interpreted by Blewett as evidence that the 100-MeV betatron orbit was contracting due to radiation loss ³ (there was another plausible interpretation) and, on the occasion of Pollock’s visual observation, suggested that the light from the synchrotron beam might be polarized. Confirmation of the suggestion proved that Blewett’s interpretation of the betatron’s orbit contraction was correct (see “The Discovery of Synchrotron Radiation,” Physics Today, January 1975, page 9 ). That took place after Blewett had left the company.

It is unfortunate that both Blewett and Pollock (also recently deceased) were never appropriately honored for their discovery of synchrotron radiation, which has made so much basic and applied science possible.

I appreciate the helpful comments Courant offered on my letter.