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Concerning the letter “APS should stick to Scientific Matters” [APS News, January 2011]: apparently, some physicists, Thomas Wolfram and Sam Werner among them, believe that climate change is a purely political matter.
I do not believe that this represents the views of the majority of physicists or APS members. Climate change, nuclear energy, anti-missile defense, and others are subjects where physicists, and APS members in general, have a special competence and should not hesitate to speak out.
Robert Levine in his 4 December letter about establishing a Topical Group on the Physics of Climate states that “The Topical Group (TG) Petition was conducted in accordance with Article VIII, Section 1 of the APS Constitution http://aps.org/about/governance/constitution.cfm, under which two hundred or more APS members may petition the Council to establish a TG. Two documents are required for the TG to be considered and established, an Area of Interest statement and Bylaws.”
This caused me to read the APS Constitution, which contrary to Levine’s implication neither requires the Council to establish the TG based on a petition, nor grants the petitioners the right to have their Area of Interest statement and Bylaws automatically approved by the Council. In fact the Constitution requires that the Council consult with all Divisions and Topical Groups before approving any new Topical Group. While it is silent about consulting with the broad membership, there is nothing forbidding this, and given the availability of email, doing so in my judgment was prudent. With respect to Bylaws, again, the Constitution places “ultimate legal and fiscal responsibility” for TG in the Council and requires the Council to review and approve or disapprove all Bylaws. Draft Bylaws submitted by petition are not privileged.
My sense of this is that petitioners may ask the Council to establish a new unit of the society, but they are not the constituting body, that before the Council approve the creation of a new TG, the entire membership of the Society shall be offered a choice to join to gauge interest and gather information, that the Council is free and it is indeed prudent for the Council to appoint an ad hoc committee to draft Bylaws and and Area of Interest statement, and finally, that the ad hoc committee, as a creation of the Council would be wise to take the documents of the petitioners into account but should solicit information from the Divisions and other units as well as the broader membership.
However, there is an underlying serious issue that the Council and the ad hoc committee should consider. Topical Groups are to be set up to “to advance and diffuse the knowledge of a specific subject or subfield of physics.” On the other hand, a Forum is an organization to advance and diffuse knowledge regarding the interrelation of physics with matters not exclusively in physics. This appears to better fit the physics of climate, which shares important aspects with many other sciences, including meteorology, geology, geophysics, chemistry, ecology, etc.
The “'scotch tape” technique for thinning crystals was in use in the late 1950s and 1960s in the UK, where the tape was called sellotape. We used it to thin crystals of molybdenite for optical absorption measurements, see the Frindt and Yoffe paper; Proc Roy Soc 273A, 89 (1963), where the work began in the end of 1959 by R.F. Frindt, who was my research student then. Frindt at Simon Fraser University developed the procedure further on, and in 1966 showed he could obtain single crystals of MoS2 several molecular layers thick; see J Appl Phys 37, 1928, (1966). Since then single layer samples have been prepared many times, and most recently a single layer transistor formed using molybdenite has been described by Radisavljevic et al in Nature Technology Letters published online 30 Jan 2011.
A. D. Yoffe
The excellent review of the history of the Van de Graaff generator and its role in the history of physics in the February number of APS News warrants some extension.
The generator was of course admirably adapted to the acceleration of charged particles. But with the discovery of the neutron by Chadwick in 1932, it soon acquired an enhanced role both as a source of neutrons and as a tool for spectroscopic investigation of neutrons produced in nuclear reactions.
It soon proved useful in both roles. The interaction of energetic hydrogen isotopes became a standard means of production of monoenergetic neutrons in the laboratory, and in the early sixties pulsing of the output of the Van de Graaff made it an admirable means of measuring neutron energies in the MeV range by their time-of-flight.
It should be noted that the conversion of the dc beam of the conventional Van de Graaff to operation as a source of ion bursts of nanosecond duration is also to be credited to Robert J. Van de Graaff. In a 1952 paper to the Denver December Meeting of the APS, he described an ingenious system of ion beam deflection in combination with a special magnet to condense ion bursts of ten nanosecond duration to less than one nanosecond (1).
Many such systems soon became operational in low-energy nuclear physics laboratories around the world and provided a rich source of data on the interaction of neutrons in the MeV range, of importance to theories of nuclear reactions, and to neutron applications to problems of nuclear reactor design for energy and military uses.
1. L. Cranberg, R. A. Fernald, F. S. Hahn and E. F. Shrader, Nuclear Instruments and Methods 12, (1961) 335-340.
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