Weinreich: Imitating Stradivarius

Weinreich’s work in Musical Acoustics

Gabriel Weinreich is an Emeritus Professor at the University of Michigan. He received a Ph.D. in Physics from Columbia University in 1953, working under the direction of the Nobel laureate, I. I. Rabi. He subsequently worked at Bell Labs on fundamental properties of semiconductors; he is credited with the theory and observation of the acoustoelectric effect, where an ultrasonic wave in a semiconductor gives rise to a direct electrical current.  In 1960 he accepted a professorship at Michigan where he became renowned for his teaching and for his lecture notes on elementary physics and on musical acoustics.  He published books on the theory of condensed matter (1965), thermodynamics (1968) and extended vector mathematics (1998).    His  contributions to research included  the discovery (with Franken, Hill and Peters) of optical harmonics, his theoretical studies of vortices in liquid helium, and his measurements of electron-atom scattering.

In the mid-1970s Weinreich turned to theoretical and experimental research in musical acoustics with a vigor that convinced the NSF to provide financial support for an extended period . His studies of the piano gave new understandings of the hammer-string interaction and of the coupled motions of piano strings.  His studies of the violin showed how the directional pattern of acoustic radiation from the instrument influences the perceived tone color.  He also invented an electronic violin bowing system and devised a new way to measure mechanical admittance in violins.   This work continued well beyond his formal retirement in 1995.

In recent years, Weinreich has collaborated with the violinmaker Joseph Curtin on the development of an electric violin that can be held and bowed exactly like a traditional violin (let’s call it a Stradivarius) but that outputs an electrical signal which, when fed into a traditional amplifier and speaker, produces the sound of the Stradivarius as it would be picked up by an excellent studio microphone.   This would meet the frequent need for a violin to be played in concert venues that demand amplified sound.


 The Weinreich-Curtin electric violin has a solid body with a normal fingerboard and with strings that are bowed in the usual way. Vibrations are picked up by several sensors, digitized, and combined in real time with the previously measured impulse response of the real Stradivarius. In this way all the bowing gestures of the violinist are combined with the playing characteristics and sound of the Stradivarius, but with an instrument that costs far less than the original.

 Links to some relevant articles
From the April, 2000 issue of The Strad: On Directional Tone Color in the Violin

NPR/American Public Media  August 15, 2013
WUNC North Carolina Public Radio Production, 9 minute audio
The Story: The Elusive Digital Stradivarius

See also the video of Weinreich’s 2012 talk at McGill University:

On the Motion of Piano Strings

Ralph Sawyer accepts a position at Michigan.

Ralph Alanson Sawyer (1895 -1978) was an active member of the Michigan physics faculty for 45 years. He had a distinguished record for pure and applied research along with a talent for administration that brought him to important positions of scientific, military, and academic leadership.   From 1919 to 1939 he rose from instructor to full professor within the physics department.  With the onset of WWII he went on active duty with the Navy and then, back as a civilian, became the scientific director of the 1946 Bikini atomic bomb tests.  The University then recalled him in 1947 to serve as dean of the Rackham Graduate School and, in 1959 added the title of vice president for research.  He was president of the Optical Society of America from 1955–57 and chairman of the board of governors of the American Institute of Physics 1959-1971.

          In 1967, Sawyer was interviewed at length by the distinguished science historian Charles Weiner; the transcript
         of their conversation is available on the AIP website.  (http://www.aip.org/history/ohilist/4856_1.html)
The following text derives and is adapted from a short portion of that interview.


Ralph Sawyer graduated in 1915 from Dartmouth and by 1919 had finished his Ph.D. under Robert Millikan at the University of Chicago.   In the summer of that year, Randall wrote a letter inviting Sawyer to join the Michigan faculty. The two men had not met, but Randall had been impressed by an article on ultraviolet spectroscopy that Sawyer and Millikan had published in the Physical Review.  Randall, knowing that that Millikan had been busy and often away from Chicago during WWI, conjectured that Sawyer had done most of the work himself and thus was capable of independent research.   The negotiations were entirely by correspondence; Sawyer first saw Ann Arbor when he arrived to join the University of Michigan faculty in September of 1919.  He retained the affiliation with Michigan for his entire career.

Sawyer came to Ann Arbor to establish a research program, but he also knew that his responsibilities included teaching.   He had been appointed as an instructor, and the standard teaching load for instructors was 12 hours per week; moreover, instructors did not have teaching assistants and so had to grade exams, quizzes, and homework themselves.   For several years, then, Sawyer had five recitation sections, about 150 students in all, every semester.

In his 1967 interview with Wiener, Sawyer recalled this load as being nearly murderous.  Nevertheless, he quickly attracted graduate students as he built a laboratory for visible and ultraviolet spectroscopy that complemented the infrared spectroscopy for which Michigan was already famous.

Paul William Zitzewitz, in memoriam

Paul Zitzewitz, 2002

PAUL ZITZEWITZ (1942-2013)

Remarks at the Memorial Gathering of 24 May, 2013
A. by Jens Zorn
B. by David Gidley

Paul Zitzewitz, who contributed so strongly to our research enterprise, had many colleagues on the Ann Arbor campus.  Four of those colleagues are with us today, and each of them could be speaking in my stead: David Gidley,  the leader of the positron group;  Ralph Conti of General Dynamics; Bita Ghaffari of the Ford Motor Company, and Rich Vallery, chair of physics at Grand Valley State University .

I also speak on behalf of dozens of Paul’s colleagues in atomic physics, a group whose members enjoy an unusual sense of community because so many of them can trace their scientific genealogy to a very few primary branches on the “Rabi Tree”.   That tree (which has 20 Nobel laureates on its branches) shows that Paul and I are scientific cousins since our thesis directors (Norman Ramsey at Harvard and Vernon Hughes at Yale) had both been students of I.I. Rabi at Columbia.

Another scientific cousin with us today, who could well be speaking in commemoration of Paul, is Robert Hilborn, a fellow Ramsey graduate student who is now, after a distinguished university career, Executive Officer of the American Association of Physics Teachers.


Paul graduated from Carleton in 1964 and entered the graduate program at Harvard.  He soon joined Norman Ramsey’s group, arguably then the best atomic experimentalists in the world with many of its graduates already in careers of unusual distinction in academia, industry, and government.

I know from personal experience that it is not easy to make the transition from being the top student in a small college, confident in one’s grasp of physics, to being a first year student in a hypercompetitive graduate school.  (I see Bob Hilborn smiling in knowing assent).    You often face the larger reality that a fundamental understanding of some topics may be beyond your talents, mastery not coming no matter how hard you try.   Your discouragement is amplified if there are others in the class who seem to master the topic with ease.   At this point you must stop obsessing over not being able to understand everything and, instead, focus on what you can do well.  You need to find a thesis advisor who will help match a research topic to your theoretical insights and your experimental talents.

Paul was an outstanding example of putting effort into those things that he could do best.

Ramsey, as one of the most influential physicists of the 20th century, was frequently away from Harvard.  He did set the general direction of the laboratory’s research, he aided in choice of thesis topics, and he did engage with critical issues when time permitted.   But the students in Ramsey’s group were largely responsible for working out the day-to-day problems of their own research, often by consulting other students and postdoctoral fellows.

Paul rose to the challenge presented by that research situation.  His doctoral dissertation was on minimizing systematic errors that affected the frequency of the hydrogen maser, this with the intent of developing an atomic clock to be used as a precise standard of time.  Metaphorically, we can regard oscillations within a hydrogen atom as the pendulum for the clock.  But motions of that pendulum were perturbed whenever the hydrogen atom bounced from the walls of its container.  Paul’s achievement was to design those walls so that the pendulum suffered only minimal perturbation as the atom underwent many wall collisions. Paul’s research provided a foundation on which others (e.g. Tom English, a Michigan PhD and a postdoc with Ramsey) built the atomic clocks now used on GPS satellites.

Transition To Dearborn

Paul finished his work at Harvard in1970, a time when the Mansfield amendment had drastically reduced the federal funding of academic research.  Universities had cut back sharply on the hiring of new faculty and   the job market for physics PhD’s shifted more to industry.  In this harsh employment climate, Paul was able to obtain a postdoctoral fellowship at the University of Western Ontario and then move to a research position at the Corning Glass Works.

Yet Paul’s drive for an academic career persisted.  His talent and accomplishments led to an assistant professorship at the Dearborn Campus of the University of Michigan, the 1973 start of the enormously successful academic career which Don Bord has so eloquently described.

Research With Positronium In Ann Arbor

After getting started at UM Dearborn, Paul’s drive to do fundamental research led to his collaboration with Arthur Rich’s large and well-funded group that was doing research on positrons on the Ann Arbor campus.   That collaboration started in the mid-1970s with studies of the interaction of positrons with surfaces and with the making of low energy, focused beams of positrons.    This opened several new areas of inquiry:  for example the availability of spin-polarized positron beams made it possible to search for the origin of the preference for left-handed twists in the molecules associated with life.

Paul also made major contributions to the group’s extensive research on the lifetime of the positronium atom.   Gidley’s early (1976) work had shown that earlier measurements of this critical quantity were probably in error.  Measurements of this lifetime formed a major portion of the group’s research effort until Vallery, Zitzewitz and Gidley published the definitive result in 2003.

Paul’s understandings have contributed immeasurably to other positron-related work, for example the APS award-winning work on chaotic transport in charged particle traps done by Bita Ghaffari, Ralph Conti and Tom Steiger.    Paul also contributed to the Positron Annihilation Lifetime Spectroscopy (PALS) for measuring nanoscale defects and open volumes being done by Dave Gidley and his students.

Paul is a coauthor of more than twenty positron-related papers, a half-dozen of which are in Physical Review Letters.  Not to be overlooked is that he was also the main conduit for news about innovations in physics education to the Ann Arbor department.

Paul was a long-term, valued member of the Ann Arbor positron group who did much for group morale.  Arthur Rich was a gifted physicist who demanded much from his students and we were fortunate that Paul, being a first-class researcher in his own right, was uniquely positioned to make friendly interventions when discussions became too intense.   Moreover, Paul was very helpful when Dave Gidley assumed leadership of the group after Rich’s unexpected, untimely death in 1990.

Concurrent Achievements

It is remarkable that Paul maintained an extended, fruitful collaboration with Ann Arbor, 25 miles away from his home base in Dearborn where he was, concurrently and for extended periods, carrying heavy responsibilities for teaching and administration, contributing to texts and outreach for K-12 teaching, and devoting time as an officer of the American Association of Physics Teachers.    We must also recognize Paul’s and Barbara’s generosity in endowing both local and national fellowships for study in physics.

Paul had an extraordinary gift for bringing out the best in others.
We were fortunate in having had him as a colleague,
as mentor, and as a friend for more than 35 years.
We are deeply grateful to Barbara Zitzewitz for
all that she did to make that possible.


David Gidley, Professor of Physics, University of Michigan, Ann Arbor

In the mid-1970s Paul had started to come out to Ann Arbor to work with Art Rich’s g-factor and positron/positronium group.  He had the idea that new areas for positron research would open up with the advent of low energy, focused beams of positrons (focused as one would do for electron beams in a cathode ray tube) and I believe that he and Art also thought the beam could be spin polarized as well.  Using what looked to us as a surplus, vintage ion pump and working on a shoe-string budget, Paul had made the group’s first “beam” of positrons—the plural here was jokingly optimistic as he struggled to find moderators to convert fast beta decay positrons into focusable low energy positrons.  He detected positrons by focusing them onto the 1 cm cone of a channel electron multiplier. The count rate was initially so low that Paul made an “up-down” counter that added counts when the beam was on and then subtracted background with the beam turned off—he was statistically digging the beam out of the multiplier’s background noise while searching for the right tune of the beam lenses.

I was minding my own business as I began my thesis experiment to measure the decay rate of ortho-Positronium (o-Ps) in some very light fluffy powders of SiO2 and MgO.  The results (1976 PRL) were startling as we deduced an o-Ps  decay rate, extrapolated to a vacuum environment, that was some 2% less than the two 0.1% measurements (at Yale and at University College London) that extrapolated over gas density.  Moreover the existing theoretical calculation agreed with the gas measurements! .  The systematic concern with all of these experiments is that you need some material to supply electrons to form the electron-positron (Positronium) bound state but then the subsequent interaction of the Ps with that same material (gas molecules or powder grains) increases the overlap of molecular electrons with the positron in the Ps, and hence increasing the measured decay rate.  The trick is to correctly extrapolate the measured decay rates to zero density. Ideally, one wants Ps isolated in vacuum.

I’m sure Paul was aware of this clear discrepancy in decay rates as there were always wonderful group discussions in Art’s group but I distinctly remember running down the hall and bursting into Paul’s corner of the lab with the question “Paul, can we put a gamma detector next to your beam to see if you are making Ps in vacuum on the cone of your electron multiplier?”  Together we jumped on this so fast that our first paper with Paul was published with the ultra-rare sans review in PRL (Paul, Art, Ken Marko, and Dave) within that same year of 1976.  The controversy only deepened as this direct measurement in vacuum nominally agreed with our powder results.  At this point we had a tiger by the tail so none of us were letting go—Paul was hooked on decay rate measurements.

We had to understand if there is something fundamentally wrong with either the gas measurements or our powder/vacuum results.  So we enlisted a longtime positron expert, Derek Paul from the University of Toronto, to work with us on our own gas experiment.  In 1978 we published another PRL wherein our extrapolation in gas density is even lower in decay rate than either the powder or vacuum results (not to mention the earlier gas experiments, now almost 3% higher).  At the same time we continued to use Paul’s ever-improving beam to improve our vacuum measurement.  I still have a Polaroid picture of Paul’s positron rate meter with a note pasted to it exclaiming the unparalleled count rate of 80 per second!  With Paul’s help modern positron beams achieve rates of over 108 per second.  This improved vacuum measurement was published in Physics Letters, also in 1978.  It would be 12 more years before we would again publish a new vacuum measurement, Jeff Nico’s thesis work, also in PRL.  In 2003 we published our final PRL on the vacuum measurement as Rich Vallery’s thesis. Paul was intimately involved in these two PhD thesis projects.

After the initial burst of decay rate activity Paul continued to work on his beam and we quickly showed that his beam is spin polarized in a 1979 PRL.  Paul’s spin polarized beam was then the centerpiece of one of Art’s pet projects, that of seeing whether the violation of parity in beta decay might underlie nature’s preference for handedness (chirality) in molecules that occur within living organisms.  (As Art was twisting the arm of our long-term NSF contract monitor Rolf Sinclair for funding of this project, Rolf quipped that we should apply to the Vatican…. and the name “Vatican experiment” stuck from then on in the group…)  Together with Paul we wrote a paper on this that was published in the prestigious journal, Nature, in 1982

In that very intense 6 year period Paul and I collaborated on 3 PRL’s, one Physics Letter, and one Nature article.  Our publication rate slowed down after that but positron beams came to be the centerpiece of my research career and much of this I owe to Paul Zitzewitz.  I became aware what a marvelous and dedicated teacher Paul became and I will let others who knew so well this side of Paul comment on it.  But I knew Paul for some 35 years first as a top notch physicist.

Dave Gidley
May 24, 2013

Paul’s obituary in Physics Today ( April 30, 2013) gives more details of his contributions to teaching.    See also the AAPT’s memoriam notice about Paul on the website of the American Association of Physics Teachers.

Michigan and the first Atomic Clock

Michigan and the First Atomic Clock

Jens Zorn,
Randall Laboratory of Physics, University of Michigan, Ann Arbor, MI 48109-1040

The first atomic clock has its origins with the research done at the University of Michigan and by its graduates over the years 1912-1948.

Although the current (2012) standard of time/frequency is based on a 9 GHz microwave transition in cesium, the first device that one could really call an atomic clock was designed and built in 1948 by Harold Lyons (UM physics PhD 1939) at the National Bureau of Standards. This clock, which predates the first cesium clock by four years, was based on the 24 GHz microwave transition in the ammonia (NH3) molecule. The existence of this transition was predicted by David Dennison in 1932; it was discovered in 1934 when the Michigan experimentalists Neil Williams and Claud Cleeton developed the magnetron tubes to produce the necessary radiation to perform the first-ever microwave spectroscopy.

But the story begins even earlier.
The theoretical understanding of the ammonia molecule rests on the experimental work started by Harrison Randall when he returned to Michigan in 1911 after working for a year on the infrared spectroscopy of atoms in Paschen’s laboratory in Tübingen. Randall built his own infrared spectrometer and initially studied some unresolved questions on the barium atom.
Then in 1913 from Berlin, Eva von Bahr published spectra arising from vibrational transitions in HCl, spectra with indications of a fine structure that was conjectured to arise from molecular rotation. Randall, whose spectrometer had a higher resolution than von Bahr’s, realized that he could resolve the question of whether molecular rotation was quantized in the same way that Bohr had assumed for electrons in his 1913 theory of the atom. Randall then directed the Michigan infrared effort toward molecules, first to diatomic molecules and then to small polyatomic molecules including NH3. The issue of quantized rotation was soon settled by Elmer Imes whose thesis experiments on HCl proved definitive , but it took longer to understand ammonia. By 1929, Barker had finally established the dimensions of the NH3 pyramid, and subsequent measurements of its spectra by Dennison and Hardy, and later by Wright and Randall, determined values for the doublet splitting of the vibrational states.
A theoretical calculation by Dennison and Uhlenbeck (1932) confirmed the dimensions and energies in this double minimum problem, however their paper does not explicitly mention the possibility of observing a microwave transition in NH3. Rather it appears that Dennison was the one who made the suggestion in 1932 that UM Professor Neil Williams and his students look for the absorption of 24 GHz radiation.


Photo of Dennison explaining to Ray Van Ausdal the focusing and state selecting action of a quadrupole field for  focusing a beam of NH3 molecules.  Dennison’s theory was the basis for the first Maser as built by Gordon, Zeiger and Townes in 1954.

In the early 1930s, no one had been able to produce controllable frequencies higher than 8 GHz with vacuum tubes, but Neil Williams had been engaged with the physics and engineering of vacuum tubes since 1924-5 during his time on leave at the General Electric laboratories in Schenectady. There Williams had worked under the guidance of A. W Hull, a pioneer in the development of the magnetron as a vacuum tube for generating very high frequencies. After his return from Schenectady, Williams did research at Michigan on aspects of electron emission but he did not particularly concentrate on high frequency generation.
Fortunately, Williams responded with enthusiasm to Dennison’s suggestion: He set Claud Cleeton, his graduate student who was already well-versed in research, to the task of building a magnetron to generate radiation of appropriately high frequency. Cleeton succeeded; he and Williams then built spectrometer to look at the absorption of microwaves by a gas of ammonia molecules. The successful results of this experiment, the first microwave spectroscopy ever done, were reported in 1934.
(Cleeton and Williams continued their development of magnetrons and by 1936 had pushed the limit for high frequency generation by vacuum tubes to 45 GHz, a new record; this led to Cleeton getting a wartime assignment to do radar development at the Naval Research Laboratory in Washington, DC )

"NH3"   --- a sculpture commemorating Michigan's discovery of microwave spectroscopy

“NH3” — a sculpture by Jens Zorn commemorating Michigan’s discovery of microwave spectroscopy

Harold Lyons was a graduate student in the Michigan Physics Department over the years 1934-39 doing a PhD thesis under the direction of Professor Ora Duffendack (who had also been in Schenectady in 1924-5). Lyons graduated in 1939 and went from Michigan to work at the Naval Research Laboratory for two years; he then joined the National Bureau of Standards and was soon chosen as chief of the Microwave Standards Section. Lyons’s familiarity with frequency standards together with the post-war availability of microwave hardware led him to build a clock based on the 24 GHz transition in ammonia. This clock consisted of a quartz crystal oscillator that was stabilized to the absorption frequency of a 8-meter-long tube filled with ammonia gas. The signal from the oscillator was then divided down to a frequency appropriate to drive an ordinary electric clock that was mounted on the front of the apparatus. This ammonia clock, the first atomic clock, was built by Lyons and his staff in the NBS Laboratories; it became operational in August of 1948,
It turns out that pressure broadening and power dependence of the 24 GHz transition limited the 1948 ammonia clock’s precision to parts in 10E+8, this not really improving on carefully-built quartz oscillator frequency standards. For increased precision it seemed promising (as suggested by Rabi and others) to base a clock on transitions observed in atomic beam spectrometer. Several laboratories (including a collaboration between Lyons of NBS and Kusch of Columbia) began working on a cesium beam clocks, and some of these became operational in early 1953. By 1967 their improved precision (parts in 10E+12) and their reliability led to the adoption of the 9 GHz hyperfine transition in cesium as the international standard of frequency. At this writing (2012), the best cesium clocks approach the 10E+16 level of precision, but it appears that optical transitions in trapped beryllium ions may offer almost two orders of magnitude improvement for the standard of time/frequency.
Given the relatively close interactions among the Michigan graduate students and faculty in the mid-1930’s, it is quite likely that Lyons knew much about Cleeton’s thesis already in 1934; moreover, after leaving Michigan both men had overlapping time in the Naval Research Laboratory in Washington, DC. Both worked on radar systems during WWII and in the immediate postwar years. (I am now looking for correspondence or other evidence that they might have had discussions of the NH3 absorption during their time in the Washington area — evidence that would link Cleeton more directly than he already is to the development of the atomic clock.)

Comment: The term “atomic clock” is here regarded as describing a timekeeper or frequency standard that uses a resonance in either an atom or a molecule, either neutral or ionized, as a reference pendulum
It is interesting to note that as ammonia was being eclipsed as a frequency standard in 1952, its very large electric dipole moment made it the molecule of choice in 1954 when Gordon, Zeiger and Townes used it as the working molecule in the first maser

Dennison on the writing of scientific papers

(from an interview conducted by Thomas Kuhn on Jan 28, 1964.   http://www.aip.org/history/ohilist/4570_2.html

CONTEXT:  As a graduate student, Dennison had requested to do his thesis research in theoretical physics (this would be the first theory Ph.D. granted by Michigan).    Guided by Walter Colby and Oskar Klein,  Dennison developed the theory to understand the infrared spectrum of methane, a project that fit well with the experimental work being done by Randall, Barker, Sleator, and others in the Michigan physics laboratories.   During the interview, Dennison told Kuhn:

At this time (1923) Oskar Klein suggested that I write a preliminary version [of the  methane paper] which I would send on to Copenhagen. . . .  I was sure that I was pretty good about writing. I was positive that I knew how to write. So I wrote a version of the thing up, and Klein sat down with me, and every single sentence was wrong, had to be revised and changed. ‘Exactly what do you mean by this, and what’s the shade of meaning here?’ and so on. Everything, piece by piece. I remember at one session I was beginning to be a little annoyed. I said finally, “Professor Klein, you would write it one way; I will write it another way. This is my way of writing it.” Klein said, “This is nonsense. There’s only one way to write a paper. If you have something to say, there is only one way; there are no two ways of writing it.” This actually, to a certain extent, was so banged into my head that I tend to believe it. I tend to believe it now that a good paper is one in which — in a sense it’s a little bit like an analytic function — each sentence has a little bit of what was past and a little bit of what is coming, so that from a portion of it you almost can reconstruct the rest. This is an exaggeration, of course. But, nevertheless, there is really only one way of writing well.

Harrison M. Randall

Harrison McAllister Randall (1970-1969) was an American physicist whose leadership over the years 1915-1941 brought the University of Michigan to international prominence for its research in experimental and theoretical physics.

Prior to 1910, the Michigan Physics Department had been focused on precision metrology.  Indeed Randall, who took all of his degrees at Michigan, had measured the coefficient of expansion of quartz for his own 1902 PhD thesis prior to his appointment to the Michigan faculty.  But a sabbatical year (1910-11) spent in Tübingen, Germany exposed him to the astonishing range of developments in modern physics; guided by Friedrich Paschen, Randall became expert in the methods of infrared spectroscopy and decided it was a promising area for development in Ann Arbor.

It was not long before Randall and his Michigan collaborators produced molecular spectra of unprecedented quality and detail.   At that time Walter Colby was the only resident theorist, so,with Randall’s encouragement,  Colby recruited Oskar Klein.  Although Klein returned to Europe after two years, the importance of theoretical colleagues was by then firmly established and it was arranged to have Otto Laporte, Samuel Goudsmit,  George Uhlenbeck, and David Dennison added to the physics faculty.   Also it was Colby’s insight and Randall’s enthusiasm that started the Michigan Summer Symposia in Theoretical Physics, an annual (1927-1941), multi-week gathering that provided short courses from prominent theorists (Bohr, Dirac, Fermi, Heisenberg, Pauli, …) to audiences that  sometimes exceeded 100 auditors.

Meanwhile, Randall also oversaw Michigan’s substantial growth in atomic physics and nuclear physics; in the mid 1930s he found the resources to build a cyclotron that was, for a time, the most energetic in the world.

Randall was elected to the presidency of the American Physical Society in 1937.  He remained as chairman of the Michigan physics department until his retirement in 1941 but continued for another 25 years to explore the use of infrared spectroscopy in biophysics.




Harrison M. Randall, On the Coefficient of Expansion of Quartz,  Phys Rev 20.   Pp 1-37.  (1905)  (this is a refinement of his 1902 thesis experiment)

H. M. Randall,  Infrared  Spectroscopy at Michigan,  Journal of the Optical Society of America, Vol. 44, pp 97-103  (1954)   (overview of work in Ann Arbor)

H. H. Nielsen, A Half-Century of Infrared Spectroscopy,  Journal of the Optical Society of America, Vol. 50, p. 1147  (1960)   (Ives medal encomium for Harrison M. Randall)

H. M. Randall and D. W. Smith,  Infrared  Spectroscopy in Biological Research,  Journal of the Optical Society of America, Vol. 53,   1086-1092  , (example of work done after his retirement)

Development of Biophysics at Michigan

 On the Development of Biophysics at The University of Michigan

 by Samuel Krimm
Professor Emeritus of Physics and Research Scientist Emeritus of Biophysics
University of Michigan, Ann Arbor, Michigan
June, 2011

Biophysics has had a long history at the University of Michigan, from its beginnings in the research of faculty members of the Department of Physics in the 1940s, through efforts to establish a department in 1950, toward the final success in establishing a University institute in 1960, and to the present formation in the College of Literature, Science and the Arts (LSA) of an Enhanced Program in Biophysics (which is equivalent to a department) in 2009. My aim here is to provide an account of the early activities, which center around the research of major individuals and their persistent actions to establish viable academic biophysics units at the University.

Individual Biophysical Research

The early development of interest in melding the disciplines of physics and biology centered on the research of scientists, primarily in the Department of Physics. It is therefore important to know the history of this evolution, particularly in its elements of marrying the fundamentals and techniques of physics with the desire to answer basic questions in biology.

Detlev Bronk. Although the most substantive efforts in biophysical studies began in the 1940s, it would be amiss not to note the singular emergence of this disciplinary vision that is associated with Detlev Bronk   This future president both of the National Academy of Sciences and of the  Rockefeller Institute of Medical Research started his scientific career at the University of Michigan. Although he enrolled in 1921 in the graduate program in Physics, working on studies of the infrared absorption of hydrogen chloride, by 1923 he was attracted to the idea of physical investigations of physiological mechanisms, encouraged by Chairman Harrison Randall “…in the belief that there is a large and undeveloped field in the investigation of physical laws in living organisms and [who] said that he would be glad to have such work carried on in his department…” (Brink, Jr., 1978).  Bronk went on to study physiology and, with Robert Gesell, published seven papers on physiological properties of the respiratory and cardiovascular systems and neural excitation of secretion from the salivary glands in mammals. In 1926 he received the Ph.D. in Physics and Physiology, the first of its kind in the nation.

Bronk’s subsequent research career continued with biophysical studies of physiological processes, and his advocacy of the discipline manifested itself in the transition of the Rockefeller Institute to Rockefeller University.

H. Richard Crane. After getting his Ph.D. at Cal Tech and doing a post-doc there, Crane came to Michigan in 1935 and soon built an accelerator to continue his research in nuclear physics.  Because of the Medical School interest in the biological effects of radiation, he started a seminar on this topic and even pursued his incipient interest in biology by attending courses in biochemistry and physiology. In the early 1940s the Bacteriology Department acquired an electron microscope with funding from the Rackham Graduate School with the proviso that the Physics Department install and run it, which naturally fell to Crane. To help visualization, he “…asked [Robley Williams] if he could evaporate a little metal onto the bacteria and viruses that were to be photographed in the electron microscope, and wondered what they would look like. The effect was striking. They looked three-dimensional.” (Crane, 1997). By 1945 Crane had perfected a shadow casting unit for the microscope, which Williams would exploit in his work.

After the war, Crane maintained activity in the biophysical area. In a paper on “Principles and Problems of Biological Growth” (Crane, June1950) he enunciated a basic idea: “The attachment of one [unit of a structure] to another was always done in exactly the same way, geometrically…The first and most striking thing to be noted in the models is that all of them take the form of a screw, or helix, which winds around a straight axis.” It is intriguing to wonder if this article influenced Linus Pauling in his seminal proposals of basic protein chain structures, since he states in his first of many papers on the subject (Pauling, Corey, Branson, April 1951) that “Hence, the only configurations for a chain compatible with our postulate of equivalence of the residues are helical configurations.” After the 1953 Watson and Crick discovery of the double-helical structure of DNA many scientists engaged in discussions of its biophysical properties, one of which was the 1956 Crane and Cyrus Levinthal (of the Physics Department) physical analysis of the proposed  unwinding of the two strands during replication. Even though he no longer worked in this area, Crane maintained an interest in the development of biophysics at Michigan.

Robley C. Williams. Williams came to Michigan in 1935 as an Assistant Professor of Astronomy, was recruited in 1941 for war work (during which he was introduced to viruses), and returned to Michigan in 1945 as Associate Professor of Physics. His work on evaporating  an aluminum coating for telescope mirrors was what induced Crane to approach him on evaporating some on viruses for possible visualization enhancement. In 1945, together with Ralph W. G. Wyckoff of the UM Department of Epidemiology, Williams  published the first electron shadow micrograph of the tobacco mosaic virus protein (Williams and Wyckoff, 1945), the forerunner of his many subsequent contributions to the study of the structure of this and other viruses.

Williams left in 1950 for Berkeley to continue his virus studies. In 1957 he was elected the first President of the recently formed Biophysical Society.

Cyrus Levinthal. After a Ph.D. at Berkeley and coming to Michigan in 1950, Levinthal turned his attention to biophysical studies. This resulted in the above-mentioned work with Crane and in an important paper on the mechanism of DNA replication (Levinthal, 1956). In this work he used 32P labeling to demonstrate that, as the replication proceeds from an initially fully labeled DNA reproducing in a non-labeled cell growing in a non-labeled medium, the label is fully retained in one strand of the double helix rather than being dispersed among the growing strands. This provided strong support for the complementary replication mechanism suggested by the double-helix DNA structure of Watson and Crick.

Levinthal left Michigan for MIT in 1957 and in 1968 he joined Columbia University as the Chairman of its newly-established Department of Biological Sciences. In subsequent work he stimulated considerations of the dynamics of how protein molecules fold into their biologically active form (“Levinthal’s paradox,” which points out that if the protein samples all possible conformations before finding its native structure it would require a time longer than the age of the universe); and he was the first to develop the basis of computer imaging of the three-dimensional structures of biological molecules.

Gordon B. B. M. Sutherland.    Joining the Physics faculty in 1949, the eminent British scientist Gordon Sutherland quickly built one of the most prominent and diverse infrared  spectroscopy laboratories in this country, thus continuing Michigan’s traditional strength in infrared research that had started when Randall returned from Tübingen in 1911.

Among the areas of research were macromolecular systems, including synthetic polymers and a continuation of his studies on biological systems. This was still the era of interpretation based on so-called group frequencies that were derived from complete analyses of the spectra of relevant small molecules, and is represented in his review on “Infrared Analysis of the Structures of Amino Acids, Polypeptides and Proteins” (Sutherland, 1952). At this point it did not seem feasible to obtain for such large molecules as polymers and proteins the kind of physical insights into structure provided by the normal mode analysis that could be implemented for small molecules. Nevertheless, Sutherland provided important continuity to the long-standing Michigan excellence in the field of infrared spectroscopy established by Randall, and he set the stage for the coming challenges to apply normal mode analysis to understanding the structure-spectrum correlations in macromolecules.

Sutherland left Michigan in 1956 to become director of England’s National Physical Laboratory and in 1964 he became Master of Emmanuel College in Cambridge.

Samuel Krimm. One of the postdoctoral fellows in Sutherland’s group was Samuel Krimm, who came in 1950 to study the infrared spectra of synthetic polymers. His initial goal was to investigate the then-unexplored far infrared region, which was accessible only at Michigan with a far-infrared vacuum spectrometer built in 1936 by Randall to obtain the long-wavelength rotation spectrum of water. Krimm’s subsequent research involved obtaining experimental spectra of a range of polymers and implementing normal mode analyses for such systems based on force fields developed from small-molecule analogs. These studies led to a deeper understanding of fundamental aspects of the structure and interactions in polymers like polyethylene and polyvinyl chloride. It was this capability that induced Krimm in the early 1970s to extend his earlier preliminary studies on protein spectra into an extensive program of normal mode analyses of the infrared and Raman spectra of polypeptides. The results of this research were summarized in a comprehensive and much-quoted review on “Vibrational Spectroscopy and Conformation of Peptides, Polypeptides, and Proteins” (Krimm, 1986). This area remained a major  component of his ongoing research program, of which other biophysically related studies included: circular dichroism investigations of the supposedly “random” chain structure of denatured proteins in solution; and theoretical studies to improve the physical accuracy of classical (so-called molecular mechanics) potential energy functions used for structure and dynamics calculations on proteins by requiring agreement with force-dependent properties such as vibrational spectra in addition to the (then-restricted) agreement with energy-dependent properties such as structure.

Others. In 1948 Harrison Randall (at the age of 78!) began a series of infrared studies on compounds found in viruses and bacteria, and was publishing papers on this work well into his 80s. Richard Sands arrived in Michigan in 1957 and soon after started his electron paramagnetic resonance and Mössbauer studies of cytochrome oxidase and other biologically important molecules.

During his 1961-69 tenure, Charles R. Worthington embarked on incisive small-angle x-ray studies of molecular organization in collagen, muscle, and nerve myelin.

After the phase-out in the mid-1970s of the department’s cyclotron and the termination of its local research program, William Parkinson turned to studies of the effects of electromagnetic radiation on biological systems.   C. Tristram Coffin shifted his interests from particle physics to biophysics.

Academic Biophysics Units

It should be clear from the above descriptions that merging the disciplines of physics and biology was embedded from the earliest times in the vision of many members of the Department of Physics. The major players also felt strongly that the key to progress in achieving this goal would depend on a parallel effort by the University to establish an academic base for defining the discipline, developing the training of students, and promoting the acquisition of financial support for research programs. As the following chronology attests, this was not to be achieved in a timely manner, dedicated people left, and it is clear that Michigan failed to capitalize on the revolution in molecular biology that was started by the 1953 discovery of the DNA double helix.


6/1949   Dean Ralph Sawyer announces the establishment of a “doctoral degree Program
in Biophysics” in the Graduate School and appoints Robley Williams as the
chairman of its implementation committee.

12/1949  Williams transmits to Dean Sawyer the Program’s recommendation for the
Ph. D. in Biophysics. Its approval remained the basis for the degree.

1950       A decision is made to create a Department of Biophysics starting in the 1950-51
academic year, but the action is rescinded by the Regents following the
resignation of Williams in June to go to Berkeley, attracted there by the virus
work  of Wendell Stanley and the opportunity to join the newly created
Department of Virology. A bachelor’s concentration in biophysics is established
in the Physics Department.

1/1951    Following the departure of Williams, Dean Hayward Keniston of LSA asks
Sutherland to “reactivat[e] a program in biophysics” by “creating a
committee which would serve to coordinate all of the interests in the field.”

7/1951    Sutherland organizes a “Summer Symposium on Biophysics” at the University.
Speakers include Salvatore Luria, J. Lawrence Oncley, Paul Doty, Ernest
Pollard, and Max Delbruck.

11/1951  Sutherland, for the Committee on Biophysics, recommends to the Division of
Biological Sciences “the early establishment of a Laboratory of Biophysics in
the Physics Department with a separate allocation of funds.”

1954       A group of physics professors, supported by Chairman Ernest Barker, submits a
proposal to the Administrative Officers “to sanction the formation of a
Biophysics Research Unit as a separate entity in the University.” Although “it
would not be expected that it would be given any appropriation…it should
receive due consideration in future appropriations… for research.”

9/1955    The Regents, on request of the Department of Physics, establish in the Graduate
School a Biophysics Research Center “to encourage research in biophysics and
to administer funds provided for research in biophysics.” Sutherland is named
Director of the Center.

9/1955    The Biophysics and Biophysical Chemistry Study Section of NIH sponsors a
“Conference on the Status of Biophysics” at the University “to discuss mutual
research and administrative problems with leaders in the general area of

7/1956    A “Summer Symposium on Biophysics” is held at the University. Speakers
include Francis Crick, James Watson, Alex Rich, Erwin Chargaff, David
Harker, Cyrus Levinthal, Gunther Stent, Seymour Benzer, Fancois Jacob,
Joshua Lederberg, Sol Spiegelman, Felix Haurowitz, and many others.

12/1958  Following the departures of Sutherland and Levinthal, Samuel Krimm is
appointed Director of the Biophysics Research Center.

1/1960    An application by Krimm to NIH for a graduate training grant is rejected,
with the following  comments: “ The University of Michigan’s early venture
into physical biology was well known as well as are more recent difficulties
which have been experienced. The failure of physical biology to develop and
flourish was a source of great concern to our consultants and a cause for inquiry
into why the environment was not a propitious one. [Our] consultants were of
the opinion that [the Biophysics Committee] was in reality largely a paper
structure which could not exercise the strong and continuing leadership in
support of the proposed program which is so necessary for its success.” The
Center decides to urge substantive University commitment to biophysics and
the search for an eminent outside Director.

5/1960    Evolving from the impact of the NIH decision, and following intensive
discussions by the Director and members of the Center with the administration,
Dean Roger Heyns of LSA and Dean William Hubbard of the Medical School,
with the concurrence of Dean Sawyer, submit a proposal to transfer the Center
to the newly formed Institute of Science and Technology (IST). They propose
that about “$75,000 of Institute funds be allocated to the support of the Center,
to be used primarily to secure one major appointment in biophysics and several
younger appointments and to provide initial research support for [these].”

6/1960    The above proposal is formalized, presented to the Regents, and accepted by
them to reorganize the Center as the Biophysics Research Division (BRD) of
IST, under the Office of the Vice-President for Research, with a Director.

6/1960    Based on earlier studies by the Center, Dugald Brown (Zoology) and Horace
Davenport (Physiology) prepare an application to NIH, submitted by Dean
Sawyer, for a Health Research Facilities Grant. Approval permits construction
of the BRD wing of the IST building on North Campus. A committee to choose
a director is formed.

9/1960   The committee to choose a Director of BRD first meets, with David Dennison
of Physics as Chairman and Dean Heyns as a member.

1961       Oncley accepts the University’s offer of the position of Director.

1962       Oncley arrives in Ann Arbor to assume the position of Director of BRD. The
Biophysical Society, established in 1957 with Robley Williams as its first
President, elects Oncley as its fourth President.

1963       The BRD wing in IST is occupied, including laboratories of several faculty
groups that Oncley brings from Harvard as well as  those of the Michigan
groups of Krimm and Sands.

1964       An NIH Training Grant in Biophysics, with Oncley as Director, is awarded for a
5-year period to support the Ph. D. program, and is renewed in 1969.

It is evident that, with the establishment of the Biophysics Research Division, the discipline of biophysics becomes embedded in the academic structure of the University. Its later history is another story, but it may be worth noting some highlights.

1) Interdisciplinary Chairs: Krimm (Physics) 1976-86; Martha Ludwig (Biological Chemistry), 1982-83, 86-89, 95-96; John Langmore (Biology), 1989-95; Rowena Matthews (Biological Chemistry), 1996-2001; Erik Zuiderweg (Chemistry, Biological Chemistry), acting chair 2001-02; James Penner-Hahn (Chemistry), 2002-07; Duncan Steel (Electrical Engineering, Physics), 2007-08; Jens-Christian Meiners (Physics), 2008-.

2) Financial Support: In addition to the University’s traditional funding of faculty salaries and other administrative support for BRD, the Executive Officers approve in 1985 the establishment of a Program in Protein Structure and Design, with Krimm as Director, that includes funding for future additional BRD faculty appointments, many of them in Physics. In 1986 the Program receives a $940,000 award from the State of Michigan’s Research Excellence and Economic Development Fund, a portion of which is used to provide new and improved equipment in BRD.

3) Division Move. In the interest of being located closer to participating departments, BRD is moved in 1993 from the IST building on North Campus into renovated space on the third and fourth floors of the 1908 wing of the Chemistry building on Central Campus. The move proves beneficial in all respects.

4) Organizational Change. In view of the increasing role of teaching in the BRD mission, Provost Paul Courant initiates in 2005 a study of whether Biophysics should be more appropriately placed as a department within LSA. This results in 2009 in the creation of LSA Biophysics, an Enhanced Program with tenure-appointing power, and the inclusion of the Undergraduate Biophysics Concentration, formerly in Physics, with Meiners as its Chair. Progress to Departmental status is envisioned, a hopeful end to a 60-year journey. 


Brink, Jr., F. (1978) National Academy of Sciences Memoir, p. 10.

Crane, H. R. (1950) Scientific Monthly 70, 376-389.

Crane, H. R. (1997) Personal Recollections.

Krimm, S. (1986) Adv. Protein Chem. 38, 181-364.

Levinthal, C. (1956) Proc. Nat. Acad. Sci. 42, 394-404.

Pauling, L., Corey, R. B., Branson, H. R. (1951) Proc. Nat. Acad. Sci. 37, 205-211.

Sutherland, G. B. B. M. (1952) Adv. Prot. Chem. 7, 291-318.

Williams, R. C., Wyckoff, R. W. G. (1945) Science 101, 594-596.

Physics Office Staff

The operation of our department depends on the intelligence, capability and dedication of our office staff.  In earlier times administrative tasks were simpler and a staff  of a half-dozen sufficed for the 48 professors that were on the physics faculty in 1960, a ratio of 1/6.  Over the decades since, the management of our teaching and research has become so complicated and demanding that the staff/faculty ratio now approaches 1/2.

For many years (during the end of Randall’s term, then for Barker and finally for Dennison)  Bernice Behrends acted as executive secretary and departmental administrator. A friendly but strong figure,  Bernice knew how to run the department.   I recall the time in August of 1962 when I went with X, another just-arrived  faculty member,  to her for dedtails about our office assignments.  She informed us, in a friendly way, that we’d be sharing a telephone.  Upon hearing this, X assumed the air of a newly-minted PhD and said “I am an assistant professor and I demand a private telephone.”  Bernice gazed at him for a moment with an air of “well, well, aren’t we important?” before repeating “you’ll share a telephone.”  When I told Peter Franken about this, he responded (in somewhat more colorful language)  “It’s OK to get crossways with me, but don’t you ever get crossways with Bernice!”

Bernice Berends illness forced her retirement during Dennison’s term as chair.  Ada Mae Newton, who had some years earlier joined our staff just after graduating from high school,  became leading administrator, a role that spanned the chairmanships of Dick Crane, Sinclair, Sands, Jones, and into the term of Homer Neal.

Sarah Albert and Marion Lammers composed our front office staff during the 1960’s.

We’ll add more much more information about staff as this website progresses with contributions from its readers.

Walt Gray

Walt Gray joined the UM physics department in 1964 after finishing his PhD at the University of Colorado. First appointed as a research associate, he soon moved to the teaching faculty as instructor (1965), assistant professor (1966) and then to associate professor in 1970,

In the late 1960s and early 1970s, Gray, together with Robert Tickle and John Bardwick, under the general direction of William Parkinson, developed a high-resolution magnetic spectrometer for use with the University of Michigan’s 82-inch cyclotron that was one of the few accelerators in the world capable of high-resolution nuclear spectroscopy. Gray and his students made a major improvement to the spectrometer by developing a position-sensitive, silicon-diode, focal-plane detector array. This permitted electronic acquisition and analysis of data in experiments that tested the collective model of nuclei proposed by Benjamin Mottelson and Aage Bohr. In particular, Gray and his doctoral student Karl Erb did studies of 205Bi and 207Bi by Proton-Transfer Reactions. (Erb later went on to a distinguished career that included directorship of the NSF program in nuclear physics and then, for many years, directorship of the NSF’s Office of Polar Programs. )

In the early years of nuclear physics, physicists very often did their experiments with accelerators associated with their own university; this was the case at Michigan. But in the mid-1970s the pattern for nuclear physics shifted to one already established by particle physicists in which experiments were more and more often done at national laboratories. Walt was involved in this; in 1980-82 he was on the executive committee of the Indiana University Cyclotron Facility users’ group. But at this time he was also responding more and more strongly to the department’s need for dedicated undergraduate teaching and advising.. Indeed, he and Robert Tickle become the anchors of the introductory physics courses, much as Wally McCormick and Wilbur Peters had been in a previous decade. Walt committed himself to undergraduates with notable success: His book Introduction to Modern Physics was published by Addison Wesley. He received Michigan’s Ruth Sinclair Award for Counseling in 1988 and, quite remarkably, its Excellence in Education Award three years in a row. He remained a strong contributor to the department’s teaching until his retirement at the end of the 2001-2002 academic year.

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Physics Instrument Shop 1900-2010 & beyond

The Michigan Physics Department had technicians to support research when they moved into the newly built West Physics building in 1889.   The technical services were vastly improved in ~1925 when Harrison Randall hired Hermann Roemer, August Wagner and several other skilled machinists along with the master glassblower Gunther Kessler .   The shop was led by Hermann Roemer (~42 years), then by August Wagner (~3 years), Paul Halloway (~12 years), Ted Webster (~25 years).    The shop had as many as ten full-time machinists in its heyday, but when Webster retired, the two remaining instrument makers, Dave Carter and Jim Tice managed the shop themselves for several years as they turned out work for many departments on campus.   (A separate student shop, overseen by one instrument maker, has existed since 1947; it continues.)

Finally, in 2010, the College of LSA decided to merge the Physics, Chemistry, and Astronomy shops into a single facility, the LSA Scientific Instrument Shop.

We’ll have stories to tell about the instrument shop as this website grows.