פרופ' דניאל אשרי - הספד
It is just about a year since Danny passed away on June 27 2018. Life seems to go on. But even in the busy life of many of us, Danny’s absence is not overcome.
I asked myself, why do I have to stand and speak or write about Danny?
Today, everyone can get with a few key strokes a full evaluation of anyone. Companies are there to provide credit reference, and in the academic world one can easily get one’s full publication list, his citation record and “a scientific grade index” based on these metrics. But still, this cannot substitute for a real evaluation of a person by the people who know him first hand.
Danny was a major founding member of the nuclear physics department at TAU , a key figure in the School of physics in general and already early on in his career, a prominent experimentalist. As such he shaped the mode of nuclear physics research activity at the University, and brought forward the nuclear physics department to be recognized as one of high standing worldwide.
Danny graduated from the Weizmann Institute in 1966 under the guidance of Gabi Goldring. WI had a strong nuclear physics department and an operating accelerator, which was the only nuclear research facility in Israel. He went then as a post-doctoral fellow to Caltech and when he returned to Israel he decided join the then young physics department at Tel Aviv University, which was just starting up. Together with Avivi Yavin RIP and then blessed to long life, Jonas Alster and Murray Moinester experimental nuclear physics started at Tel Aviv. But it was with a new twist. Looking backwards, they made a major decision. They did not join the existing accelerator as partners, or attempted to build one at Tel Aviv. In a small and isolated country, that would be of a limited scale and one did not expect then scientific collaboration in the middle east. Worldwide, new accelerators which were built in the mid-seventies provided intermediate-energy beams of pions and electrons and opened up new directions of nuclear research. The group decided then to operate as a Users Group, embark on new directions and perform experiments at the leading facilities in the world.
Danny’s leadership, both as an outstanding physicist and personality were probably the key to this mode of work. It opened the way to a very successful career, not only personally but to put the Tel Aviv group as a major team in the international league.
Danny was a pioneer in the field of pion-nuclear interactions. The new field and his personality drew students as well as young faculty to join him and enjoy the collaborative work.
Danny did not look to join an experiment, be it as interesting as it may be. Rather, after facing an interesting idea, he would think of the best accelerator facility where the experiments can be performed. This would require a presentation to the accelerator Advisory Committee, getting approved, build and set up the detectors and perform the experiments. Then, bring the data to Tel Aviv, where they would be analyzed. This, required good computers, compatible with those available and used in the accelerator laboratories.
The first experiments were carried out at Saclay and then at SIN (PSI), Los Alamos and TRIUMF. With his suggestions of new experiments he was welcome at each laboratory with the Tel Aviv group, and we who followed him enjoyed a warm hospitality and the support of the laboratories. He was recognized for his work on pion nuclear interaction and was elected as a Fellow of the American physical society. But at the same time he encouraged new ideas by his fellows, was ready to join their experiments and took care and made sure that credit was given also to his juniors. That made him a true leader of the group and a scientist we all enjoyed to work with.
Some of Danny’s research was conducted also with large collaborations. Here again, he did not just join the experiment, but brought new ideas to be investigated, with added value to the experiment and with a Tel Aviv name-tag. This was at Fermi Lab and throughout the later years at TRIUMF.
But as I mentioned, this mode operation required adequate computation facilities locally. While today, a CPU in a cell-phone is probably stronger than a major computer in 1975 it was not a trivial task in those days. Danny saw the importance of setting up a first rate Data Analysis laboratory, and saw that it would be equipped with the state of the art computers. This way, the analysis could be carried on at Tel Aviv, and keep this activity at home. I’ll never forget the first VAX which Danny managed to get to our department. I don’t even know how he did it, but there it was, available just like we saw at MIT or PSI. Obviously, on a smaller scale, but more than sufficient for the group.
Danny did not seek power. His good-nature attitude to his colleagues, in particular his juniors, made him a natural leader also in the everyday life in the School of Physics. He did not ask for it, but was asked to Chair the School which he agreed to do on the condition that he’ll do it only for a couple of years. Being a very good lecturer either in graduate courses or in popular lectures which he gave on the Broadcasted University he used his term to advance student laboratories and new programs. The senior-student lab took a major face lift with new experiments – making sure that the students will be exposed to the experimental side of physics.
Thinking about it in retrospective, he was a person – or a leader we simply liked to follow. Even after he was formally retired, he never stopped ‘doing’ physics which was his first love, I assume even before sailing. But moreover, we always turned to him when major decisions had to be taken, like the future of nuclear physics in Israel, new directions to be developed in the school and so on. Always ready to listen, to give advice and suggest, to those who were interested, a relaxing sail during the weekend.
So, we all miss you. As I said in my parting words, we physicists learned how to detect signals from far away stars and galaxies. Even though we do not see you sitting at your desk when passing your room, we keep our sensors tuned so that we can still hear what you would say about this or that, and keep your legend with us.
May 26th, 2019