Bill Zajc's memories of Ken Crowe
Ken Crowe was an enabler, in the very best sense of the word. He enabled each of his students to pursue a direction of his (I do not know if Ken had any female students) choosing. Once the direction was set, Ken provided support, resources and his own unique form of encouragement. I know this was true in my own case, and my entire subsequent career is directly attributable to his guidance during my time as a graduate student.
I approached Ken in 1977 at the end of the summer following my second year in graduate school. I had done nothing that summer other than read a little physics between workouts and parties. I had somehow developed an interest in soft-pion theorems and current algebras, and asked if I could do a thesis that combined experimental work with some phenomenology. Ken agreed immediately, and was instrumental in getting me paid quickly when he inferred I was dead broke. I honestly don't know if he thought it was possible to do what I proposed, but his willingness to make an on-the-spot decision encouraged me enormously.
At the time I joined Ken's group, he had a major program in muon spin resonance at TRIUMF, and was gearing up for a radiative pion capture experiment at LAMPF (Los Alamos) that would be Jeff Martoff's thesis experiment. I was building power supplies, impressing Jim Bistirlich with my ability to produce cold solder joints and trying to determine if radiative capture on tritium could help understand the 3-neutron final-state interaction (this went nowhere). At some point early in 1978, I attended a seminar in the Nuclear Science Division by a Miklos Gyulassy, then a post-doc at LBNL (now a valued colleague at Columbia). Miklos spoke about using two-pion interferometry to search for coherent pion emission in heavy ion collisions, in rough analogy to two-photon interferometry (the Hanbury-Brown-Twiss effect) in astronomy. I had learned just enough from Gordon Baym's QM text about HBT to be dangerous, and these ideas really intrigued me. I tried to explain them to Ken, perhaps the same afternoon. I am sure my attempts to explain coherence were incoherent, but in the end he asked me, "Why don't you think about how to do an experiment to measure this stuff?"
From that point on, I was obsessed with the topic. I knew nothing about experimental design, but with huge amounts of help from members of the group (and Miklos) managed to cobble together a design that resulted in a proposal to Bevalac Review Committee in April, 1978. We received some lukewarm encouragement, but by November, 1978 had full approval; this after spending the summer with the group's attention focused on the experiment at LAMPF. At the time, I was frustrated with the time spent away from "my" experiment. In hindsight, I realize what an extraordinary gift Ken gave to me -- a flaky graduate student interested in a flaky experimental technique in a flaky (in Ken's view) field is given the go ahead to pursue an entirely new effort in a small group that was undoubtedly cash and resource strapped. Extraordinary indeed, and a tribute to Ken's ability to see and to seize a physics opportunity.
Of course, much of this work took place in response to Ken's "own unique sense of encouragement". He was literally hopping mad the morning of the presentation to the Bevalac Review Committee when I informed him I had just discovered a factor of 6 error in the rate calculation (of course in the wrong direction; I was so ignorant I had not realized the Bevalac was a pulsed machine). He could not hop while he was driving me and a (greatly embarrassed) Japanese collaborator back to the mesa in Los Alamos, but he made it clear how stupid my design was for a counter mount. These were painful, but well-deserved, moments in my education as a graduate student. Ken was decades in front of the "tough love" movement, but he was a master at it. It helped tremendously to know that through it all, he supported his people. I have a vivid memory of a telephone conversation coming through his closed office door at very high volume as he dressed down the head of the lab's Real Time Systems Group -- one of the RTSG techs had manage to wipe out my entire collection of good events I had spent weeks culling from tapes processed by our PDP-11. Ken got the tech assigned to go through the same multi-week exercise, freeing me to work on other parts of my data analysis.
Upon graduating, I went off in a somewhat different direction from Ken's main interests, and never had the opportunity again to collaborate with him. I take some small solace in knowing that the last two times we met, at a symposium celebrating Miklos Gyulassy's 60th birthday -- see http://www-nsdth.lbl.gov/mg60/program.htm -- in 2008 and at Berkeley Physics Colloquium last fall, I had a chance to publicly acknowledge my indebtedness to him. I only wish that I could have one more chance to do so, for he was a most extraordinary mentor.
