R/V Franklin followed a drifter for 8 days in the equatorial Indian Ocean to test the accuracy of mixed‐layer heat and freshwater budget closure. Four‐hourly triangles were repeated, towing a SeaSoar with a photometer and conductivity‐temperature‐depth (CTD) profiler. Currents relative to the buoy at one depth were obtained from (a) a current meter at 25 m below the buoy; (b) a Global Positioning System estimate; (c) a drag estimate. Acoustic Doppler current profiler (ADCP) shears provided currents at other depths, (b) and (c) agreed closely but differed from (a), possibly due to severe conditions at the current meter. Vertical advection was estimated from ADCP divergence around each triangle. Measurements on the buoy and the ship, calibrated earlier in the Coupled Ocean‐Atmosphere Response Experiment (COARE), provided bulk surface fluxes. Accuracy of net surface heat fluxes was estimated at ±10 W/m 2 . Rainfall differed considerably between the buoy and ship, but other quantities including shortwave radiation were very similar, even on cloudy days. A formalism for the budgets above a given isopycnal is developed, to clearly distinguish horizontal and vertical advection. When (b) and (c) above were used with the best estimate of surface fluxes, the 8‐day heat budget misclose for water above the 21.5 isopycnal was (−4.6±5) W/m 2 ; the diurnal heating cycle was well resolved. The freshwater budget misclose was (0.9±3.5) mm/d. A small amount of vertical diffusion, in the ratio determined by the slope of the T‐S curve, will reduce both misclosures. Cruise design considerations for minimizing errors in the advection and storage components of heat and freshwater budgets are discussed.

Studies have been made of the approach to energy-loss and charge-state equilibrium of initially pure charge states of ions, transmitted through thin carbon targets. Ions of Li, F and C1 at 3 MeV per AMU were used. Detailed observations were made of outgoing energy losses and charge-state distributions, for outgoing charges equal to those ingoing. A Monte Carlo analysis is made of the charge changing processes, which allows calculation of energy losses due to projectile charge exchange. The residual electronic target-ionisation loss is analysed to predict in-target charge states of the projectile ions. Using these, a comparison is made between the in-target effective charge for target ionisation, and the averaged ionic charge which fits charge-exchange data.

An experimental arrangement is described to. detect delayed X-rays emitted fo.llo.wing fo.il excitatio.n o.f 130 MeV Br io.ns at distances to. 190 mm do.wnstream o.f a self-supPo.rting carbo.n target. The intensities o.f L X-rays at a number o.f distances were measured. The o.bservatio.ns are discussed in terms o.f the decay o.f high- n Rydberg io.ns. It is sho.wn that, in additio.n to. the expected yrast cascades, there are o.ther little-understo.o.d cascades with high intensities.

A study has been made of the approach to charge equilibrium of charge-selected 130 MeV Cl ions incident on a range of self-supporting carbon targets. Outgoing charge distributions were accurately recorded with the focal-plane detector of an Enge spectrograph. Fits to the data were made using a Monte Carlo method with theoretical expressions for capture, loss, excitation and de-excitation. The fits are reasonably consistent with predictions, although there is evidence that standard capture and loss cross sections are inadequate for a full description of charge exchange in the solid.

A method is described for the measurement of pre-charge-state-equilibrium energy losses of heavy ions in solid targets. Preliminary results for 130 MeV 35 Cl incident on carbon targets between 3 and 130 μg/cm 2 thick are reported to demonstrate the techniques. The results are described in terms of the Bethe formula for energy loss.

AbstractWe show that the Rutherford backscattering technique is very useful for studying the kinetics of diffusion processes in polymers. We have measured the diffusion of iodine into low‐density polyethylene (LDPE) by optical absorbance and by Rutherford backscattering. The optical results appear to be normal, and show no electric field dependence, but the backscattering results reveal that this is misleading, because there is fast diffusion in the bulk accompanied by large surface concentrations of iodine. We have studied PET by the backscattering technique, and in this case the behavior corresponds to a weakly concentration‐dependent diffusion coefficient with no observable surface effects. Neither set of results gives support to the domain theories of low‐frequency electrical oscillation in these materials.

Charge-state distributions of 130-MeV Br ions have been measured as a function of incident ion charge for a preequilibrium- and an equilibrium-thickness carbon target. These measurements lead to a relatively simple interpretation of the charge-exchange processes and are compared with the predictions of the Bohr-Lindhard and Betz-Grodzins models.

Studies have been made of projectile X-rays from K and L vacancies produced in Br ions bombarding thin carbon targets. Characteristic K lines are observed, while L radiation is identified from L to M and L to N shell vacancy transitions, as well as radiative electron capture into the L shell.

Low-energy X-rays (1–4 keV) have been detected under bombardment of light-ion targets by Br ions of 70–130 MeV, at incident charge states between 9 + and 28 + . Evidence from X-ray spectra is presented that the radiation comprises L X-rays, enhanced in energy by a factor of over two by the effects of the ions' motion in the target. A qualitative discussion is given of the observed perturbations in relation to the polarising forces expected in solid and gas targets.

Constructional details are given of an inexpensive and easily made self-latching electromechanical shutter. The device is based upon a conventional blade type shutter and should find uses in a wide range of applications other than the vacuum evaporation unit for which it was designed.

With a high-resolution Si(Li) X-ray detector, characteristic K X rays have been detected with targets of Cr, Fe, Cu, Ge and Se ombarded by 100 MeV Cu ions, equilibrated by passing through carbon. Cross sections for X-ray production, target-to-projectile vacancy-sharing ratios and K, to K, ratios were measured and compared with predictions of molecular-coupling theories. The results show little greement with existing models based on rotational coupling in molecular-orbital states.

Electrical noise measurments have been made on thin films of PS, PE, and PET, over the frequency range 10−4–1 Hz, the temperature range 20–80 °C, and under applied fields up to destructive breakdown. The noise power is found to be less than the measurable limit of 10−29 A2/Hz until near-breakdown fields are applied, at which time a rapid increase in noise is observed with noise-power spectra varying with frequency as 1/fα, with 1.3<α<1.7, and proportional to the square of the steady current. Very similar characteristics were observed in all three polymers. We give a tentative explanation for this high-field phenomenon in terms of the activation of sensitive spots, thermal runaway, and subsequent annealing.

A microprocessor-based system for measuring low-frequency (less than 100 Hz) electrical noise power spectra is described. The main function of the microprocessor was to determine the noise autocorrelation function using simple ''one bit'' autocorrelation arithmetic, subsequent Fourier transformation to find the power spectra being done on a larger computer. Given that such larger computing facilities already exist, this system is much less expensive than more conventional analogue techniques. We illustrate the way in which this system was implemented to measure current noise in insulating polymers.

In a recent paper Bosacchi, Franchi, and Bosacchi claim that the shape of a thermoluminescence glow curve may be taken as a reflection of the distribution function with respect to the activation energy of a continuous electron trap distribution, even when electron retrapping occurs. It is shown that, under such conditions, the glow-curve profile may differ significantly from that of the trap distribution.

Both the dielectric and conduction properties of many organic materials, including polymers, are profoundly affected by the trapping of electrons at various sites in the samples. A wide range of experimental techniques have been devised to investigate these traps, the most common relying on the analysis of phenomena, e.g. luminescence and electrical conductivity, arising from thermally-stimulated liberation of electrons from traps. Such investigations can be expected to lead to a more detailed characterisation of the samples. Thus, in organic polymers, the “glow” peaks resulting from electron detrapping can frequently be correlated with the onset of particular types of molecular motion, e.g. segmental chain motion on passing through the glass-to-rubber transition temperature Tg. Although this transition usually occurs within a given sample over a relatively narrow temperature range, typically 2–3 K wide, the associated glow curves in samples with negligible temperature gradients frequently exceed a half-height width of 20 K. One therefore suspects the existence of an effective quasi-continuous distribution of trap depths, the analysis of which could lead to a more complete understanding of the inter-chain conformation. Alternatively, glow peaks can sometimes be associated with a variety of β or γ transitions, e.g. motion of the pendant phenyl group in polystyrene, or with an impurity acting as an electron trap in various sites throughout the sample bulk. In both cases, one would expect an effective quasi-continuous distribution of trap depths, especially in amorphous materials, because of the variation in the surroundings of the phenyl group or impurity.

The authors describe a numerical technique for analysing thermoluminescence data when the thermoluminescence process involves a quasi-continuous distribution of activation energies, and first-order kinetics. The technique proceeds by synthesis of glow curves, isothermal decay plots and thermal quenching cycles until agreement with the experimental data is obtained. A possible method of documenting the spread of glass-to-rubber transition temperatures in organic polymers by analysis of thermoluminescence data in the appropriate temperature region is discussed.

An experimental investigation of thermoluminescence glow curves, thermal quenching cycles and isothermal decay plots in polystyrene has been carried out. It is concluded that the luminescence emission process follows first-order kinetics with respect to the concentration of trapped electrons, and that a quasi-continuous distribution of electron trap activation energies exists. The distribution of occupied electron traps immediately after irradiation peaks at 0.08 eV and stretches from a maximum lower bound of 0.05 eV to an upper cut-off of 0.45 eV. The effects of addition of various organic dopants, the application of an electric field, and increasing irradiation dose on the thermoluminescence emission have been investigated.

Two distinct forms of memory switching have been observed in thin films (500–4000 Å thick) of glow discharge polymerized styrene, acetylene, benzene, and aniline. These two forms, called the high-voltage switching regime (HVSR) and the low-voltage switching regime (LVSR) are characterized by high (≳20 V) and low (1–5 V) threshold voltages, respectively. Their occurrence depends on three parameters; namely, electrode thickness, film thickness, and the nature of the ’’forming’’ atmosphere. The low-resistance (switched on) state of both modes is associated with highly conductive filaments. It is suggested that in the HVSR the filaments are metallic and result from localized fusing of the two electrodes, the intervening polymer film having been completely vaporized. In the LVSR the filaments are thought to be of carbon, formed from localized pyrolysis of the polymer film.