At Goddard we worked down the hall from our colleagues in the X-ray group. We were testing a lot of stuff for the COBE in advance of launching the instruments -- checking the susceptibility of our detectors to cosmic rays, and so on. We were detecting gamma rays using our instruments to see how they would respond so that we would know how they’d behave in space. We were also looking at various semi-conducting materials, like indium, for use in the detectors. The X-ray group down the hall was doing something similar, but using silicon diodes to detect X-rays.

One day the X-ray guys came down the hall -- they knew that we were looking at other semi-conductors rather than silicon -- and they asked me if I thought our indium detectors we were going to use for COBE would be a good alternative to the silicon detectors for detecting X-rays. “Well, let me think,” I said. “I don’t think these indium detectors will work, but I have here in my drawer a calculation that shows that a thermal detector, where you measure the temperature change, will work very well for you.” They couldn’t believe it. So I said, “Let me see if I can find it, and then tomorrow I will come down and talk to you about it.”