Velocity-space sensitivity of the time-of-flight neutron spectrometer at JET

The velocity-space sensitivities of fast-ion diagnostics are often described by so-called weight functions. Recently, we formulated weight functions showing the velocity-space sensitivity of the often dominant beam-target part of neutron energy spectra. These weight functions for neutron emission spectrometry (NES) are independent of the particular NES diagnostic. Here we apply these NES weight functions to the time-of-flight spectrometer TOFOR at JET. By taking the instrumental response function of TOFOR into account, we calculate time-of-flight NES weight functions that enable us to directly determine the velocity-space sensitivity of a given part of a measured time-of-flight spectrum from TOFOR

On the mechanisms governing gas penetration into a tokamak plasma during a massive gas injection

A new 1D radial fluid code, IMAGINE, is used to simulate the penetration of gas into a tokamak plasma during a massive gas injection (MGI). The main result is that the gas is in general strongly braked as it reaches the plasma, due to mechanisms related to charge exchange and (to a smaller extent) recombination. As a result, only a fraction of the gas penetrates into the plasma. Also, a shock wave is created in the gas which propagates away from the plasma, braking and compressing the incoming gas. Simulation results are quantitatively consistent, at least in terms of orders of magnitude, with experimental data for a D 2 MGI into a JET Ohmic plasma. Simulations of MGI into the background plasma surrounding a runaway electron beam show that if the background electron density is too high, the gas may not penetrate, suggesting a possible explanation for the recent results of Reux et al in JET (2015 Nucl. Fusion 55 093013)

Relationship of edge localized mode burst times with divertor flux loop signal phase in JET

A phase relationship is identified between sequential edge localized modes (ELMs) occurrence times in a set of H-mode tokamak plasmas to the voltage measured in full flux azimuthal loops in the divertor region. We focus on plasmas in the Joint European Torus where a steady H-mode is sustained over several seconds, during which ELMs are observed in the Be II emission at the divertor. The ELMs analysed arise from intrinsic ELMing, in that there is no deliberate intent to control the ELMing process by external means. We use ELM timings derived from the Be II signal to perform direct time domain analysis of the full flux loop VLD2 and VLD3 signals, which provide a high cadence global measurement proportional to the voltage induced by changes in poloidal magnetic flux. Specifically, we examine how the time interval between pairs of successive ELMs is linked to the time-evolving phase of the full flux loop signals. Each ELM produces a clear early pulse in the full flux loop signals, whose peak time is used to condition our analysis. The arrival time of the following ELM, relative to this pulse, is found to fall into one of two categories: (i) prompt ELMs, which are directly paced by the initial response seen in the flux loop signals; and (ii) all other ELMs, which occur after the initial response of the full flux loop signals has decayed in amplitude. The times at which ELMs in category (ii) occur, relative to the first ELM of the pair, are clustered at times when the instantaneous phase of the full flux loop signal is close to its value at the time of the first ELM

Supplementation of grazing dairy cows with a brewers grains/treated straw mixture

Supplementary feeding of grazing dairy cows is often uneconomic, and whilst supplementation with silage (buffer feeding) can be worthwhile, this often leads to a depletion of winter forage stores. In this study, a mixture of brewers grains and treated straw was used as a supplement. Offered as a 1:1 mixture in the dry matter (DM), it is a purchased substitute for grass silage, having a similar cost, and similar metabolisable energy (ME) and crude protein (CP) contents. The high seasonality adjustments to milk price in mid-late season make supplementation potentially worthwhile.Experiments were carried out from April to September in 1988 and 1989, which had moderate and very low rainfall respectively. Each year 20 British Friesian cows which calved December to March (1988 experiment) and February-April (1989) were allocated at random to either treatment B or C. In B, the cows were offered a 1:1 mixture (DM basis) of brewers grains and NaOH treated chopped barley straw for 60 minutes after morning milking. In C, the cows received no supplement. Both groups were fed 1.0 kg/day of concentrates in the milking parlour. Due to the severe drought in 1989, concentrate feeding was increased to 5.0 kg/day for all cows during the last 4 weeks of the experiment. Also, urea-treated whole crop wheat was fed at a level of 2.5 kg DM/day during the last 7 days.</jats:p

Evaluation of a slow release form of recombinantly derived bovine somatotropin (BST) in dairy cattle

Two experiments were conducted with British Friesian/Holstein cattle to evaluate the response in milk production to the long-term use of recombinantly derived bovine somatotropin in a slow release form (somidobove, Lilly Research Centre Ltd). The first compared three doses of BST and the second measured the effect of BST given to animals receiving two levels of concentrates.Thirty-eight and forty autumn calving cattle were used in experiments 1 and 2 respectively. A randomised block design was used in the first experiment and a 2 x 2 factorial in the second. Animals were blocked on the basis of similarity in calving date and milk yield during the preliminary period. Treatments were allocated at random within blocks, animals remained on the same treatment throughout each experiment. In experiment 1 animals received seven successive subcutaneous injections of BST at intervals of four weeks, the initial injection was given about 11 weeks after calving. A control and three doses of BST were compared: 320, 640 and 960 mg. In experiment 2 animals were given given six injections of 640 mg BST at the same intervals.</jats:p

Comparison of rapeseed meal, sunflower and soyabean meals as protein sources in concentrates for milking cows

A compound feed that is designed to be given in equal amounts with cereals for milk production would contain about 30% crude protein, and if rapeseed meal were the major high protein supplement to be used along with cereal, about 60% would need to be included. No observations have been reported in which this high proportion of rapeseed meal has been used and the experiment described was planned to provide this information, using low glucosinolate rapeseed meal. The control diet contained soyabean meal in place of rapeseed meal, and a third compound was used containing sunflower meal seed as the major protein supplement.Thirty-nine Friesian cattle were used in a randomised block design: the three treatments, compounds containing low glucosinolate rapeseed meal, sunflower seed meal and soyabean meal, were applied for 16 weeks. There were 21 cows and 18 heifers, the mean days in milk at the start of the experiment was 62 days and the mean yield over the previous two weeks was 26.9 kg.</jats:p