Multiwavelength Astronomy

Photo of Stirling Colgate

Gamma Ray History, Stirling Colgate

Experimental Physics at Cornell

When I returned to Cornell after the war ended I shifted my major from Electrical Engineering to Physics. One of the most difficult Physics courses was the X-ray lab. The experiments demanded that you really understood the physics of X-ray formation and scattering and all the properties of X-rays that are so much a part of atomic physics.

By sheer good luck I teamed up with a guy who loved theoretical problems, and with me being a nuts and bolts experimentalist with a lot of imagination, we were, quite frankly an awesome team. Time and again our professor would comment, “How did you modify that experiment so that it now works?” To us it was a no brainer. It was what we really loved and we rebuilt quite a few experiments. With that reputation, many of the professors would ask me what kind of an experiment could be developed to measure, for example, high-energy helium nuclei. And so I built several of these experiments, always with all kinds of encouragement from the professors and major help from the department machine shop.

I went on to get my Ph.D. at Cornell. That fall, the professor took me aside and said “Look, this lab is going to be yours while I’m away. I have funds from the National Bureau of Standards for us to do a sequence of gamma-ray measurements. Everyone in the physics department knows you can be original, Stirling, but quite frankly, no one knows if you can do an experiment reliably, accurately, and with great care. When I come back, I expect you to have this done.” He went on to say that it was probably impossible.

The measurements needed were coefficients of gamma rays, which would be used to accurately calculate nuclear bomb debris. As an undergraduate I had spent a lot of time taking gamma-ray absorption measurements. Now this became a defining part of designing an experiment to find out what goes on in a hydrogen bomb (H-bomb) explosion. While my professor was away I got the whole thing done, and some of those measurements are still fundamental to the Bureau’s database.

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This material is based upon work supported by NASA under Grant Nos. NNX09AD33G and NNX10AE80G issued through the SMD ROSES 2009 Program.

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