3. Luie

      I had originally gone to the University of California at Berkeley, in 1964, to become a nuclear physicist. I finished most of my course work within a year, but I knew I still had a lot to learn. The real problems to solve are not the ones at the end of each chapter in the textbook. The real problems come in dealing with the unexpected. The questions are vague and fuzzy. How do you pick a research topic? How long do you study a subject before you publish? What do you do when things don't look like you expected them to look, when your results surprise you? How do you recognize when to quit a not-completely-hopeless endeavor? Coping with these problems is the art of physics, and it is very similar to the art of business, or the art of art. You can learn it only from another physicist. So once you have finished your graduate courses, you are expected to apprentice yourself to one, your "thesis adviser."

      The cutting edge of nuclear physics was a subfield called "elementary particle physics," the study of the "elementary" bundles of energy from which everything else in the Universe is constructed. In this field Berkeley was the center of the world. Almost every day some great scientist passed through Berkeley, pausing at the Lawrence Berkeley Laboratory to hear about the latest discovery. More rarely the scientist would tell about some new discovery made elsewhere. The vocabulary of the particle physicist was already colorful, with "strange particles" and the "eightfold way" being common lunchroom topics. It seemed as if a giant jigsaw puzzle had been laid out, and everyone was trying to fit the pieces together. But, as opposed to working a real jigsaw puzzle, in this case nobody knew what the picture would look like at the end, or what the boundaries of the puzzle were. Different groups specialized in different parts of the puzzle. It was a research area in which many people could work together, be they great scientists or only mediocre. Some people would fit more pieces together than others, and some were particularly good at finding that hard piece, the one that everyone else had given up on. But everybody was able to find some little way to help. Even though it was a fast-moving business, it looked to an outsider as if there was still a lot to do. There was bound to be a corner where even a graduate student could contribute. Maybe I could even be lucky and make a discovery.

      One afternoon as I walked into an office shared by graduate-student teaching assistants (TAs), my friend Calvin Farwell was telling the other TAs about a new project just being started by Professor Luis Alvarez. Alvarez wanted to use cosmic rays, the intense radiation that comes from space, to study the properties of elementary particles. It was an extremely difficult and complex undertaking, for most of the radiation never reaches the surface of the Earth but is stopped by the blanket of the Earth's atmosphere. So, he explained, Alvarez was going to fly a complete elementary particle physics experiment from the bottom of a huge bal loon, over 100 feet in diameter. Since there was no electrical power up at the top of the atmosphere, he planned to use superconducting magnets, a brand-new and untested technology Neither spark chambers nor bubble chambers would work, and Alvarez had come up with a new kind of detector, something that combined spark chambers with nuclear emul sions in a clever way that made them far more effective together than they could have been separately.

      I was entranced. Alvarez was famous as the man who had turned the bubble chamber into the primary discovery tool in elementary particle physics, but he was now abandoning it and inventing something new, something unheard of, to address new unsolved problems in an original way. The only question in my mind was whether such a great man would ever accept me as a student. I don't think I considered it a serious possibility Instead of graduate students, Alvarez preferred having a dozen young Ph.D.s working for him, and these he treated as graduate students. But then I had a bit of luck. I became the head TA for Physics 4A in the new fall semester, and Alvarez was scheduled to teach it. So I would naturally meet the man and be able to make my own evaluation, without having to take the psychological risk of appearing to be soliciting a thesis adviser.

      When I walked into the Physics 4A laboratory the next fall to have a meeting with the other TAs, there was a tall, blond, athletic-looking man wearing a sports coat sitting at one of the laboratory benches. He intro duced himself with "I'm Luie Alvarez," avoiding the title "professor," which many other faculty members obviously favored. He said that he was there to help me organize the laboratory I told him that he was welcome to attend our meeting but that I had an agenda already worked out. He promised not to interfere. He sat through the hour-long meeting, and listened patiently as I explained to the new TAs what their duties would be, how to prepare for the labs, and how best to guide the students. At the end of the meeting he came over to me and said that he clearly wasn't needed, so if it was okay with me, he would skip future TA meetings. I was both surprised and flattered.

      I attended a few of his lectures to the huge class of about 300 students, and found his presentations very lively and interesting if not totally organized. Alvarez loved to sprinkle his lectures with personal stories from his experiences in the lab. All of physics seemed to have direct meaning to his own life and research experience. He didn't just practice physics, he lived physics.

      I finally got my courage up, and after one class I asked him about his balloon project. We immediately sat down in the large Physical Sciences Lecture Hall. He wanted to know why I was interested. I said the project was obviously exciting. I didn't want to become a bubble-chamber physi cist, or a particle-counter physicist, or a spark-chamber physicist, but just wanted to learn how to do experiments, experiments that had never been done before. It seemed to me that that was what his balloon project was all about. He told me I was absolutely right and suggested that I come up to the Radiation Lab right then to see the actual hardware and meet some of the people already working on it.

      We drove up the hill on which the Lawrence Radiation Laboratory was located, along winding Cyclotron Road and through a forest of towering eucalyptus trees. This laboratory is devoted to basic research in science. Unlike the more famous Lawrence Radiation Laboratory located at Liver more, it does not engage in nuclear weapons design or other classified research. Alvarez didn't slow down as the guard waved him through the gate. The view from the hill was spectacular, with the entire San Francisco Bay area laid out below us. Two deer scampered off the road in front of our car. Alvarez explained that the deer had a refuge within the fence that divided the laboratory from the rest of the world. The road continued to wind, but buildings began to appear among the trees, steam rising from some of them. "That's the Bevatron," Alvarez said, pointing to a huge circular building with a flashing light on the door. It was the big accelera tor that had been built by Ernest Lawrence, the Nobel laureate who had created the laboratory and had been Luis Alvarez's mentor. The Bevatron was used in most of the great discoveries made at the lab.

      Finally we came to a long corrugated-metal building named, simply, Blg. 46. Inside were dozens of people in shirtsleeves working at benches and drafting tables and machines. Alvarez took me to a small area partitioned off from the rest, where a heavyset young man rose at our approach. He was William Humphrey, a physicist who was running the day-to-day activities of the project. To use a simile from the business world, Alvarez acted on the project like the chairman of the board, but had recently delegated the role of president to Humphrey I was somewhat dazzled as Alvarez and Humphrey showed me around the rest of the building. I saw a difficult and complex project with many elements, each of which looked too complicated for me to understand, and a crew of several dozen physicists, engineers, machinists, and technicians all work ing together with a single goal, which had been defined by Alvarez. Alvarez always liked to take the lead in explaining the apparatus scattered around the building, but he always deferred to Humphrey for details. At the end of the tour, Alvarez asked me, "When can you start?" I had not understood much of what I had seen, and I didn't think I had asked any intelligent questions. In addition, Alvarez hadn't had a chance to check my grades or to look at my record in the Physics Department office, so he had no way of knowing whether I was a good student. But it was an offer I couldn't refuse.

      Everyone in the Alvarez group called him Luie, except me. Alvarez had continued the tradition of informality that Ernest Lawrence had begun decades earlier. But I had been brought up to call all people older than myself by a title. Since I couldn't be the only one in the group to say 'Professor Alvarez," I avoided calling him anything. It made it sound as if I had forgotten his name.

      Alvarez's whole approach to physics was that of an entrepreneur, taking big risks by building large new projects in the hope of large rewards, although his pay was academic rather than financial. He had drawn around him a group of young physicists anxious to try out the exciting ideas he was proposing. Many of these people were later to leave basic research and become entrepreneurs themselves of one kind or another. The true rewards for this kind of work were in the challenge, in the adventure. Alvarez seemed to care less about the way the picture in the puzzle would look, when everything fit together, than about the fun of looking for pieces that fit. He loved nothing more than doing something that everybody else thought impossible. His designs were clever, and usually exploited some little-known principle that everyone else had forgotten.

      I decided that my first job was to read and understand the long memo he had written on the balloon project. What was most striking about the memo was that Alvarez had no background in superconductivity, yet he was proposing to use state-of-the-art technology in this new experiment. But he had obviously done a lot of "homework," spoken to real experts, and convinced himself that there were no insurmountable obstacles to the new superconducting magnet. There were no known particle detectors that would work with sufficient precision in the confined space of a gondola hanging from a balloon. Alvarez had addressed this problem by inventing a new kind of particle detector, which combined the best features of some of the existing detectors, including spark chambers and nuclear emulsions, scintillation detectors, and a gas-filled Cerenkov detector. The concatenation of new technologies was overwhelming. It seemed to me that Alvarez must know everything there is to know in science.

      I enjoyed the thought of working with things that I didn't really under stand. Perhaps I had inherited this trait from my father, who loved to repair our TV set when I was a child. He had very little understanding of how the thing actually worked, but that never stopped him from fixing it. He opened the back, carefully defeated the interlock mechanism, and began sniffing around. Sometimes he would notice a tube wasn't lit. Other times he would find a capacitor (then called a "condenser") that smelled funny. In retrospect, I realize that what he was doing was the essence of good science. You look for something that smells funny, and you explore around it. You don't always understand what you are doing; if you do, it probably means that you aren't really near the forefront of knowledge. My dad was a detective, a solver of mysteries. He had a finely tuned nose, like Alvarez.

      One day Alvarez noticed me sitting in an office reading, and asked what I was doing. I proudly told him how hard I was working on my "homework," his memo.

      "You'll never learn experimental physics by sitting at a desk," he abruptly said. "Get over to Building 46, where the real physics is being done!"

      I was embarrassed. "But I don't understand anything yet. I don't know how to help. I'd just be in the way," I protested.

      I remember his answer very clearly "That doesn't matter," he said. "just go over there and hang around. Do anything anybody asks you to do. Sooner or later someone will see that you're there, and they'll ask you to hold a screwdriver. Get your hands dirty Pretty soon you'll know how things are constructed. Once they have seen that you're around a lot, they may ask you to help test the apparatus. Before long you'll know how everything works. You can read memos anytime, in the evenings, at home, but you can only learn experimental physics by being in the laboratory, by doing it."

      The next time Alvarez saw me was in BIg. 46, where I was helping test some spark chambers. We exchanged smiles. The part I had thought most difficult to learn, understanding the hardware, had turned out to be the easiest. But just as Alvarez had said, I couldn't learn it by reading memos or published papers. Even today, when I visit someone's laboratory and they sit me down in a nearby office to hear a lecture on their experiment, I protest. I want to go see the hardware, if possible to touch it.

      As I have grown older, I realize that I am spending more and more time at a desk, planning new projects (as Alvarez had, in his memo) rather than building apparatus, rather than doing experiments. But even now a certain minimum contact with the hardware is absolutely necessary. In the Greek legend, the wrestler Antaeus was invincible as long as he touched the ground. Hercules defeated him by lifting Antaeus above his head, out of reach of the Earth, where he was able to squeeze him to death. This legend may have originated as a reminder to farmers to stay in close touch with the land, the source of their sustenance, and not to relegate all the manual work to hired laborers. The reminder applies equally well to experimental physicists, who must return periodically to their apparatus, to get their hands dirty, lest they forget why it often takes an hour to put in a screw.

      A few weeks later I was helping another graduate student, Dennis Smith, mount a large photomultiplier tube in the Cerenkov detector, and I dropped it. It imploded just like a TV picture tube, with a loud and sickening crash. I had just destroyed $15,000 worth of hardware. Dennis consoled me. It could happen to anybody, he said. I thought it might be the end of my career. Fifteen thousand dollars was twice what I earned in a year as a research assistant. Some of the money could be recovered by firing me. A short time later I saw Alvarez, and confessed what had happened. "Grrrrr. . . reat!" he roared, and put out his hand as if to congratulate me. He shook my hand vigorously, but I protested. "Wel come to the club," he continued. "Now I know you're becoming an experimental physicist." To become a real member of the Mafia you have to murder someone. To become an experimental physicist, Alvarez seemed to feel, you had to destroy some expensive equipment. It was a rite of passage. "Don't do anything differently," he advised. "Keep it up."

      To my awe of Alvarez was added that day a feeling of warmth. I overcame my shyness, and finally managed to address him as Luie.

      After that Luie and I grew close. I became almost a scientific "son" to him. He shared not only his scientific ideas but also his thoughts on life and the world. I sensed that he truly appreciated my interest in learning from him, and I was very grateful for all the time he began to give me. It was still impossible to keep up with him in physics matters, to compete. I never seemed to have any idea that he hadn't thought of and dismissed years ago. It was hard on my ego. But then I did something that was one of the finest moments in my life. I made a truly great decision, one that determined my entire career. I said, quite consciously, almost aloud, "To hell with my ego!" I decided that the opportunity was simply too great. One of the great physicists of all time was aching to teach, and I would do everything I could to learn from this man. I would totally follow his suggestions for what projects to work on. If he had a new idea, I would drop whatever I was doing to work with him on it. My goal for the next several years would simply be to learn as much as I could about how Luie thought, how he approached physics, how he decided what to do, how he followed though. I would apprentice myself fully to Luie. I would not leave Berkeley until I felt that I was no longer learning.

      What makes a good scientist? As the years began to pass, I noticed that the smartest students didn't always become the best researchers. That gave me some hope, since my course work was only slightly better than average. What was it they hadn't learned? I was awed by the careers of several of the faculty at Berkeley. There were more Nobel laureates at Berkeley than in the entire Soviet Union. And there was Luie, who had no Nobel Prize then but seemed to have more important discoveries to his credit than any of the scientists who had won the honor.

      I made a mental list of Luie's great discoveries. He proved that cosmic rays were positive, probably protons; he discovered several rare isotopes; he discovered the radioactive process called "electron capture"; he found internal conversion in light nuclei; he discovered the magnetism of the neutron; he found the radioactivity of tritium; and he was responsible for a whole book of discoveries in elementary particle physics. To this list I could add several major inventions. He invented the triggering system for the atomic bomb (and flew in the chase plane over Hiroshima to measure the bomb's yield); he also invented ground-controlled approach (GCA), widely used for blind aircraft landings. But it wasn't the art of invention, but the art of discovery that I most wanted to learn. How did he do it? What secret knowledge enabled him to make discovery after discovery? If only I could identify what it was, then I could try to learn it.

      Skepticism, the ability not to be fooled, was clearly important, but it is also cheap. It is easy to disbelieve everything, and some scientists seemed to take this approach. Sometimes Luie was skeptical, but more often he seemed to embrace crazy ideas, at least at first. He rarely dismissed anything out of hand, no matter how absurd, until he had examined it closely. But then one tiny flaw, solidly established, was enough to kill it. His openness to wild ideas was balanced by his firmness in dismissing those that were flawed. He had a finely honed skepticism. Perhaps that was part of his secret talent.

      Scientific training doesn't keep your senses from fooling you, but a good scientist doesn't accept the impressions his senses deliver. He uses them as a starting point, and then he checks, and double checks. He looks for additional evidence, and for consistency among his measurements. A scientist differs from other people in that he knows how easily he is fooled, and he goes through procedures to compensate.

      Luie had learned about the art of discovery from his father, Walter Alvarez, a physician and medical researcher, famous for his newspaper medical column "Ask Dr. Alvarez." Some people also gave him credit for restoring the prestige of general practitioners at a time when specialists had been getting all the attention. His son had obviously learned at least one great lesson from his father, for Luie had become a general practi tioner of physics. The senior Alvarez believed the key to discovery was not being "lazy." He had come very close to winning a Nobel Prize in medicine. He had had the idea of treating pernicious anemia with liver, but he had never really followed up on his observations. He had been too lazy, or perhaps too skeptical. The hardest discoveries to take seriously are often your own. A few years later, George Whipple and others pursued the liver-treatment idea, developed it into the standard method of curing the disease, and were awarded the Nobel Prize in medicine. Walter Alvarez never came that close to a Nobel Prize again, but he made sure that his son learned the lesson.

      Luie had no Nobel Prize, but he believed that he had narrowly missed winning it at least twice. He had almost discovered fission, the "trans mutation of the elements," when he was bombarding uranium with neutrons. He would have found it if he had run his apparatus for a half hour instead of just a few minutes. When he read in a newspaper that fission had been discovered by Otto Hahn in Germany, he was imme diately able to confirm the discovery, but it was too late. It was not his discovery.

      The second Nobel Prize he missed was the discovery of secondary neutrons from fission, the process that makes the chain reaction possible. Luie had produced neutrons with the cyclotron, and bombarded various materials with them. He had all the apparatus needed to see that some times when a neutron hits a uranium nucleus, two neutrons come out, but he hadn't looked long enough. One neutron can lead to two, two to four, four to eight, and so on; about seventy-five generations later virtually every atom in the sample has emitted a neutron, unless the tremendous heat generated has blown the sample apart. The chain reaction is the basis for the nuclear reactor and the atomic bomb.

      The art of physics consists in knowing what to work on and for how long. Many physicists have wasted their careers following up on uninter esting discoveries. But to me, as a graduate student awed by Luie's successes, it was not easy to discern a pattern behind his choice of projects. His balloon project was clearly exciting, although perhaps too difficult to lead anywhere. Soon after Ijoined this experiment, Luie began the pyramid project. It looked like fun, but it wasn't the sort of project I had expected a world-class physicist to work on.

      Luie had read about the pyramids as a child, much as I had read about the dinosaurs. He had read of how Howard Carter had found the tomb of Tutankhamen by a combination of meticulous planning and preparation mixed with a good deal of daring. From his readings Luie was convinced that there were other unfound chambers, probably in the pyramids at Giza themselves. If success means to have a dream of childhood come true, then Luie's crowning success would be his discovery of a hidden chamber full of gold, treasures, and history. And in 1966, Luie finally thought he had invented a method of looking inside the pyramids, tantamount to x-raying them. His idea was to apply the methods of nuclear physics to archeology, to use a special kind of penetrating natural radioactivity (muons) in place of x-rays.

      Luie worked out virtually all the details before he even told anybody what he was thinking of, and he put these in a memo. Real x-rays wouldn't penetrate deeply enough into rock, so Luie planned to use muons, ele mentary particles created by cosmic radiation from space, that can pene trate hundreds of meters of rock. To estimate the flux of muons, Luie used a rule of thumb: roughly 1 cosmic-ray muon passes through your thumb every 10 seconds as part of the natural organic radiation that always surrounds (and penetrates) us on Earth. All the details were worked out before any apparatus was built. It was experimental physics from a desk. Many scientists think that experimentalists don't think; they work with hardware. Luic believed that you had to know and understand a subject thoroughly before attempting a measurement.

      I was beginning to see, in the way Luie worked, a possibility for my own research. There were always others far more talented in mathematics than me, and there were always others far more scholarly and comprehen sively knowledgeable. I had found physics frustrating because there was too much to learn. But Luie's approach to physics wasn't mathematical or comprehensive; it was clever and inventive. He had learned just enough about every subject; he could go back and fill in the gaps later, when and if that was necessary. The gaps in his knowledge were surprisingly large, but not detrimental to his work. Even though he knew little about quan tum mechanics, he had discovered internal conversion in light nuclei, an extremely important and unexpected quantum-mechanical process. His knowledge of theoretical optics was extremely spotty, yet he had used diffractive optics in a clever and original way to invent a method of landing airplanes during conditions of zero visibility. (For the invention of this ground-controlled approach during World War II, Luie had won many awards and been thanked by hundreds of pilots who owed their lives to him.) He seemed to have a knack for learning just the right amount about everything, and for spending the time he saved inventing and bringing together ideas from disparate fields.

      Luie's pyramid project was an adventure, science being used for explo ration. He believed that he had inherited the legacy of the great explorers. He had read and reread the journals of Sir Richard Burton, the first non- Muslim to enter Mecca, and of Captain James Cook, explorer of the Pacific. Explorers must be prepared for the unexpected. They must be ready to allow fate to lead them in new directions. They have to be broadly educated and aware of where the true frontiers are. Science is the modern- day tool to explore the world. The real excitement in science is the excitement of discovery, particularly the discovery of something you had no reason to expect was there.

      Luie claimed to be driven by a sense of curiosity, but if that were true he could have spent his time becoming a scholar. With so much physics to learn, why work hard trying to discover a few small facts in physics that nobody else knows? The truly curious don't waste their time fitting together jigsaw puzzles, since there were so many beautiful pictures to be seen in books and museums. Does anybody really solve jigsaw puzzles in order to see the picture? No, they do it because of the fun of solving the myriad of little puzzles along the way. Luie was a puzzle solver, an adventurer, an explorer.

      Of course, not all explorations succeed. Ponce de Le6n never did find the Fountain of Youth. Luie found no chambers in the pyramid. Some newspapers mistakenly reported that he hadn't found any chambers, and Luie was quick to point out their error. He did more than search without success; he had searched and found that there were no chambers inside. The problem with risk-taking is that sometimes you fail. Resiliency is not a virtue for research in physics; it is an absolute necessity.

      One morning in 1968 I was having trouble tuning the radio to the morning news. What I heard was "garble. . . garble. . . Nobel Prize in chemistry . . . garble . . . garble . . . physics . . . garble . . . garble . . . Alvarez . . . garble . . ."

      I ran into the next room looking for my wife, Rosemary, shouting, "Luie won the Nobel Prize! Luie won the Nobel Prize!" I lifted her up in the air and spun her around, surprising myself with my own strength. We stopped dancing for a moment as I suddenly wondered if I had misheard. It made so much sense to give him the prize, but I thought Luie had missed his chance when the award had been given to Donald Glaser several years earlier for the invention of the bubble chamber, the device that Luie had perfected and used for myriad discoveries of elementary particles. All my joy was based on one word, which I might not have heard correctly I called up the lab, and got Luie's secretary on the phone. "Ann, I just heard on the radio ..."

      "Yes," she interrupted, "isn't it wonderful!" I rushed to the lab. Everyone was celebrating, waiting for Luie to show up. He had been called at home, early that morning, by a newspaper reporter. The prize was given for all the discoveries that had come from the bubble chamber. Luie was the sole physics winner that year.

      There was cheering down the hall, and I guessed that Luie had finally arrived. Everybody was deliriously happy For someone with a reputation among outsiders as a tough curmudgeon, Luie had obviously generated a great deal of loyalty and love among those who had worked with him. I was even surprised at my own happiness. It was the most exciting day of my life.