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The commentary focuses on Gould’s idea of NOMA, according to which science and theology are two Non-Overlapping Magisteria. The term “non-overlapping” is appropriate because methods of validation of claims in these two fields of intellectual investigation. are different, not because the areas of investigation should be different. The author was once an active atheist, in Poland; now he is a practicing theist, belonging to a Reform synagogue in the United States. He thinks that Gould’s idea, if universally accepted, could help to reduce intensity of dangerous doctrinal confrontations between theists and atheists, and between different groups of theists. The commentary ends by a quote from a statement about desirable collaboration between religion and science, made by Pope John Paul.

We have measured the temporal duration of 45 MeV picosecond electron beam bunches using a noninvasive electro-optical (EO) technique. The amplitude of the EO modulation was found to increase linearly with electron beam charge and decrease inversely with distance from the electron beam. The rise time of the temporal signal was limited by our detection system to ∼70 ps. The EO signal due to ionization caused by the electrons traversing the EO crystal was also observed. It has a distinctively long decay time constant and signal polarity opposite to that due to the field induced by the electron beam. The electro-optical technique may be ideal for the measurement of bunch length of femtosecond, relativistic, high energy, charged, particle beams.

For central collisions of 17-115 A MeV {sup 40}Ar+Cu , Ag, Au, an overall balance is determined for the average mass, energy, and longitudinal momentum. Light charged particles and fragments are separated into forward-focused and isotropic components in the frame of the heaviest fragment. Energy removal by the isotropic component reaches 1-2 GeV. For such high deposition energies, statistical multifragmentation models predict much more extensive nuclear disassembly than is observed. (c) 1999 The American Physical Society.

Experiments performed at Lab. Nat. SATURNE on neutron produced by spallation from proton beams in the range 0.8 - 1.6 GeV are presented. Experimental data compared with codes show a significant improvement of the recent intra-nuclear cascade (J. Cugnon). This is also true in the same way for the neutron production from thick targets. However the model underestimates the energetic neutrons produced in the backward direction and other quantities as residual nuclei cross sections are not accurately predicted.

Measurements are reported for fragment masses and velocities from the reactions $(17--115)A\mathrm{MeV}$ ${}^{40}\mathrm{A}\mathrm{r}+\mathrm{C}\mathrm{u},$ Ag, and Au. Charged particle multiplicities were used to select the most violent reactions, and systematics are reported for the momentum and energy deposition. These reactions are fusionlike for $\ensuremath{\lesssim}44A\mathrm{MeV}$ ${}^{40}\mathrm{Ar}$ with a large fraction of momentum and energy deposition in the heavy nuclear system. However, for $\ensuremath{\gtrsim}44A\mathrm{MeV}$ ${}^{40}\mathrm{Ar},$ a majority of the projectile energy and momentum is carried away by a multibody spray of light ejectiles and only a minority is deposited in the heavy nucleus. Nevertheless heavy composite systems are formed with up to 9--12 MeV per source nucleon for $115A\mathrm{MeV}$ ${}^{40}\mathrm{Ar}.$

We present the experimental method conceived to measure high energy neutrons in the range (200 ≤ E ≤ 1600 MeV). The neutrons produce recoil protons in a liquid hydrogen converter. Momentum evaluation and identification of these protons are made by using a magnetic spectrometer equipped with plastic scintillators and three double-plane ( X - Y ) wire chambers. The response functions of the apparatus are determined using quasi-monoenergetic neutron beams produced by the break-up of deuterons or 3 He on a Be target. The performance of the apparatus is illustrated in the form of a preliminary neutron spectrum.

We present an experimental method based on a time-of-flight technique between the tagged incident particles and a thick liquid NE213 scintillator to measure neutron energy spectra from 3 to 400 MeV at the Saturne synchrotron of Saclay. Efficiency measurements are made using a pulsed neutron source from the Tandem Van de Graaff of Bruyeres-le-Châtel at low energies and a quasi-monoenergetic neutron beam at Saturne up to 50 MeV.

Students can use a simple electrical circuit to demonstrate behaviour that is usually ignored in textbooks. A discussion of the activity and the properties of such capacitors in series is given here.

This article describes a simple nonlinear mechanical oscillator suitable for an undergraduate physics laboratory. The oscillating system is a Plexiglas blade, with nonlinearity introduced by means of contact with stretched rubber bands. Using a variable driving frequency, students can make amplitude and phase lag measurements with sufficient accuracy for quantitative work. It is possible to study classical resonance with the linear system and then, with the modified system, produce nonlinear effects such as hysteresis.

Heavy residual nuclei are shown to result from the most violent (i.e., central) collisions for {sup 40}Ar + Ag reactions of up to 1.36 GeV; their average velocities are {approx_gt}80{percent} of the c.m. velocity. Angular and energy distributions for {sup 1,2,3}H, {sup 3,4}He, and Li are measured in coincidence with these heavy nuclei. The dominant light particle components are nearly isotropic in a frame of reference having the velocity of the heavy residues. In addition there are forward-peaked high-energy components of the H, He, and Li emission attributable to prethermalization emission. Fractional abundances of these prethermalization components increase markedly with increasing incident energy. Mass and momentum balance preclude the presence of a projectilelike fragment and thus indicate fusionlike reactions with large but incomplete linear momentum transfer. The remainder of the momentum is carried away by the spray of forward-peaked ejectiles. For 1.36 GeV {sup 40}Ar {approximately}1/2 of the 900 MeV available is completely thermalized, and {approximately}1/2 goes into prethermalization emission after strong collisional mixing. {copyright} {ital 1996 The American Physical Society.}

This article describes lecture demonstration apparatus for displaying free and forced oscillations of a mechanical system to a large class. The setup described won first prize at the AAPT apparatus competition in August 1994. A Plexiglas blade clamped at one end is magnetically driven by a low‐frequency generator–amplifier. The frequencies are so low (between 0.2 and 1.2 Hz) that visual observations of displacements are possible. The driving voltage, associated with the force applied, is visualized with a row of 20 light‐emitting diodes, a laser pointer projecting displacements, and a photosensor providing sound cues for phase references. Dependence of amplitude and phase on frequency can be seen, heard, and recorded by a large group of students. The apparatus is simple enough to be replicated and used at all levels of physics teaching. Technical details on the LED display unit, and some theoretical considerations, are described in two appendices.

Lifetime measurements are crucial for our understanding of the dynamics of reaction processes. Nuclear reactions often occur too rapidly for direct measurements of the times involved. Here we describe a newly developed and actively used method for studying decay processes for very hot nuclei (e.g., with temperatures of ≳1010 K or ≳2 MeV) and in particular the associated time scales of ≊10−20–10−22 s (or ≊3000–30 fm/c).

In-plane and out-of-plane angular correlations have been measured between fragments of {ital Z}{gt}3, Li fragments, {sup 3,4}He, and {sup 1,2,3}H. The changing patterns for {sup 40}Ar induced reactions of 7{ital A}, 17{ital A}, 27{ital A}, and 34{ital A} MeV give an overview of the decreasing importance of mass-symmetric fissionlike reactions at the expense of a broad range of more mass-asymmetric breakups. Evidence is given that these fragments come from a central collision group of reactions that have similar violence and from which many combinations of fragments and particles are ejected. Very similar azimuthal angular correlations are observed for particles with a Li fragment and for particles with a pair of heavier fragments ({ital Z}{gt}3). This similarity suggests comparable strengths of association with the reaction plane for single Li fragments and for fragment pairs of {ital Z}{gt}3. Azimuthal angular correlations for Li-Li pairs exhibit distinct asymmetries; their interpretation via trajectory-model calculations indicates mean delay times of {approx}5{times}10{sup {minus}22} s.

“I am sure that you are aware of the DOE move to review the cold fusion field, as reported in The New York Times (3/25/04). Attached is a review article that, I hope, can be published in Scientific American. The title is “Recent cold fusion claims: are they valid?” It is not a paper defending cold fusion claims; it is a paper describing them, no matter what one is inclined to think. Scientifically literate readers are likely to appreciate my short summary of recent claims made by cold fusion researchers.

After familiarizing himself with the use of CR-39 detectors, about a year ago, the first author asked Steven Jones to send him a TiDx foil, similar to that described at the Tenth International Conference on Cold Fusion (1). It was an attempt detect 3 MeV protons with the CR-39 chips. The idea was to develop an experiment suitable for student-oriented cold fusion projects. That is how the first author became a cold fusion researcher. After receiving the foil he sandwiched it between two CR-39 detectors for the period of 55 days. The area of each detector was one square inch. The exposure started three days after the sample was prepared (by keeping the titanium foil in deuterium gas at high temperature and pressure).

What follows is a collection of messages about cold fusion from teachers. The messages were posted on the Internet discussion list, Phys-L, or were sent to me in private. They illustrate a wide range of opinion. PHYS-L is a list dedicated to learning and teaching physics with 700 subscribers from over 35 countries, the majority of whom are physics educators. .

1) A year ago I would have replied that cold fusion is pseudoscience. But I am no longer comfortable with this kind of reply. Why am I not comfortable? My first opinion was based on Huizenga’s famous ERAB report. I knew the author personally and I respected him. His criticism of cold fusion was convincing because it was based on the idea that cold fusion is a thermonuclear reaction between two colliding hydrogen ions. Experimental data certainly do not support such an idea. But who made this claim? Only the popular press and those who criticized cold fusion. Fleischmann and Pons, who discovered excess heat, speculated that some kind of nuclear processes might be responsible for what they observed. The very name “cold fusion” was highly unfortunate because it misled many scientists, including myself. Who invented this term? Was it introduced deliberately (as a straw man) to discredit the nascent field of research? I have no answers to such questions. But I suspect that this misleading term will survive the controversy; that is why I decided to use it here.

We have made an observation of 45 MeV electron beam bunches using the nondestructive electro-optical (EO) technique. The amplitude of the EO modulation was found to increase linearly with electron beam charge and decrease inversely with the optical beam path distance from the electron beam. The risetime of the signal was bandwidth limited by our detection system to \~70ps. An EO signal due to ionization caused by the electrons traversing the EO crystal was also observed. The EO technique may be ideal for the measurement of bunch structure with femtosecond resolution of relativistic charged particle beam bunches., 3 Pages, 1 figure. Presented at DPF2000 conference at Ohio

We have made the first observation of a charged particle beam by means of its electro-optical effect on the polarization of laser light in a LiNbO3 crystal. The modulation of the laser light during the passage of a pulsed electron beam was observed using a fast photodiode and a digital oscilloscope. The fastest rise time measured, 120 ps, was obtained in the single shot mode and was limited by the bandwidth of the oscilloscope and the associated electronics. This technology holds promise for detectors of greatly improved spatial and temporal resolution for single relativistic charged particles as well as particle beams., 7 pages, 2 figures. Published in Nucl.Instrum.Meth.A452:396-400,2000

The ensemble of charged isotropically emitted ejectiles is studied for central collisions of $(17\ensuremath{-}115)A$ MeV ${}^{40}\mathrm{Ar}\mathrm{}+\mathrm{}\mathrm{Cu},$ Ag, Au. Measurements of average multiplicities, spectral slopes, and masses of the heaviest fragments are compared to statistical models for multifragmentation or sequential evaporation. The multifragmentation models predict much more complete nuclear disassembly than is observed. The evaporation model reproduces the data much more closely except for the spectra of $Z=1$ ejectiles. The kinetic energies of $Z=1$ and 2 ejectiles are much less than found for $1A$ GeV ${}^{197}\mathrm{Au}{+}^{12}\mathrm{C}$ for similar energy depositions. Entrance channel dynamics seem to affect the isotropic emission ensembles, often taken to define an equilibrated emission source.

We have made the first observation of a charged particle beam by means of its electro-optical effect on the propagation of laser light in a birefringent crystal at the Brookhaven National Laboratory Accelerator Test Facility. Polarized infrared light was coupled to a LiNbO/sub 3/ crystal through a polarization maintaining fiber of 4 micron diameter. An electron beam in 10 ps bunches of 1 mm diameter was scanned across the crystal. The modulation of the laser light during passage of the electron beam was observed using a photodiode with 45 GHz bandwidth. The fastest rise time measured, 120 ps, was made in the single shot mode and was limited by the bandwidth of the oscilloscope and the associated electronics. Both polarization dependent and polarization independent effects were observed. This technology holds promise of greatly improved spatial and temporal resolution of charged particle beams.

Spallation neutron production in proton induced reactions on Pb targets at 0.8, 1.2, and 1.6 GeV has been measured at the SATURNE accelerator. Double-differential cross sections were obtained over a broad angular range from which averaged neutron multiplicities per reaction were inferred for energies above 2 MeV. The results are compared with calculations performed with a high energy transport code including two different intranuclear cascade (INC) models: it is shown that the Cugnon INC model gives a better agreement with the data than the Bertini one, mainly because of improved nucleon-nucleon cross sections and Pauli blocking treatment. © 1999 The American Physical Society.

Light charged particles from the reactions 247 and 337 MeV $^{40}\mathrm{Ar}$${+}^{\mathrm{nat}}$Ag have been measured in singles and in coincidence with fission-like products. Most of the $^{1}\mathrm{H}$ and $^{4}\mathrm{He}$ in coincidence with fusion-fission and quasifission can be accounted for by evaporation from the composite nucleus or by the fragments. Multiplicities are determined for $^{1}\mathrm{H}$ and $^{4}\mathrm{He}$ in association with evaporation residues, fusion-fission, and quasifission. The probability for composite nucleus emission decreases with increasing spin zone of the emitter and gives a view of the role of emitter lifetime. The ratio of composite-nucleus multiplicities for quasifission/fusion-fission is about 1/2 ((1/4) for 337 MeV $^{40}\mathrm{Ar}$ (247 MeV $^{40}\mathrm{Ar}$) which implies a similar ratio for the lifetimes of the respective composite nuclei between thermalization and scission. Energy spectra and angular distributions of particles (in coincidence with fusion-fission and quasifission) are consistent with emission from a strongly distorted nuclear system en route toward scission. Prethermalization emission of $^{4}\mathrm{He}$ is observed at 10\ifmmode^\circ\else\textdegree\fi{} in comparable amounts for peripheral collisions (quasifission and fusion-fission) and for central collisions.

The binary fission process in Au and U induced by 12 C at 30, 60 and 84 Me u has been investigated. Excitation energies of the fused nuclei are inferred from the mass measurements as a function of the transferred linear momentum. Incomplete-fusion models appear to account for the bulk of the data. The variance of the mass distribution of the fragments increases roughly linearly with the temperature derived at saddle point as expected in a thermal process.

Cross sections for evaporation residues following complete fusion have been measured for the bombardment of $^{27}\mathrm{Al}$ with 81-, 105-, 126-, and 168-MeV $^{16}\mathrm{O}$, 138- and 210-MeV $^{20}\mathrm{Ne}$, and 336-MeV $^{32}\mathrm{S}$. The results were obtained using a counter telescope and, in some cases, differ considerably from previous work with mica track detectors. The experimental critical angular momenta for fusion are in good agreement with recent theoretical calculations for the O and Ne bombardments. Our data suggest parameters for the critical distance of approach which are significantly smaller than previously reported values.

Angular correlations have been measured between heavy fragments in $^{86}\mathrm{K}$R + $^{197}\mathrm{Au}$ reactions using two gas telescopes. The data have been analyzed to yield a separation of two-body from multibody events. The assumption that sequential fission accounts for all multibody breakup allows the determination of sequential fission probability as a function of inelastic energy transfer. Comparison to fission excitation functions for similar heavy compound nuclei provides insight into the deposition of energy and angular momentum. For $\ensuremath{-}Q$ of \ensuremath{\approx} 200 MeV or E* \ensuremath{\approx} 140 MeV typical spin values of $30\ensuremath{-}40\ensuremath{\hbar}$ can be estimated for the heavy (Aulike) fragments.