Design of the ion-optics for the MRSt neutron spectrometer at the National Ignition Facility (NIF).

A new Magnetic Recoil Spectrometer (MRSt) is designed to provide time-resolved measurements of the energy spectrum of neutrons emanating from an inertial confinement fusion implosion at the National Ignition Facility. At present, time integrated parameters are being measured using the existing magnet recoil and neutron time-of-flight spectrometers. The capability of high energy resolution of 2 keV and the extension to high time resolution of about 20 ps are expected to improve our understanding of conditions required for successful fusion experiments. The layout, ion-optics, and specifications of the MRSt will be presented.

Top-level physics requirements and simulated performance of the MRSt on the National Ignition Facility.

The time-resolving Magnetic Recoil Spectrometer (MRSt) for the National Ignition Facility (NIF) has been identified by the US National Diagnostic Working Group as one of the transformational diagnostics that will reshape the way inertial confinement fusion (ICF) implosions are diagnosed. The MRSt will measure the time-resolved neutron spectrum of an implosion, from which the time-resolved ion temperature, areal density, and yield will be inferred. Top-level physics requirements for the MRSt were determined based on simulations of numerous ICF implosions with varying degrees of alpha heating, P2 asymmetry, and mix. Synthetic MRSt data were subsequently generated for different configurations using Monte-Carlo methods to determine its performance in relation to the requirements. The system was found to meet most requirements at current neutron yields at the NIF. This work was supported by the DOE and LLNL.

Distribution of collected target debris using the large area solid debris radiochemistry collector.

A large area solid radiochemistry collector was deployed at the National Ignition Facility (NIF) with a collection efficiency for post-shot, solid target debris of approximately 1% of the total 4π solid angle. The collector consisted of a 20-cm diameter vanadium foil surrounded by an aluminum side-enclosure and was fielded 50 cm from the NIF target. The collector was used on two NIF neutron yield shots, both of which had a monolayer of 238U embedded in the capsule ablator 10 µm from the inner surface. Fission and activation products produced in the 238U were collected, and subsequent analyses via gamma spectroscopy indicated that the distribution of fission products was not uniform, with peak and valley fission products preferentially collected on the vanadium and low- and high-mass fission products primarily located on the aluminum side-enclosure. The results from these shots will be used to design future nuclear data experiments at NIF.

Aperture design for the third neutron and first gamma-ray imaging systems for the National Ignition Facility.

The current construction of a new nuclear-imaging view at the National Ignition Facility will provide a third line of sight for hotspot and cold fuel imaging and the first dedicated line of sight for 4.4-MeV γ-ray imaging of the remaining carbon ablator. To minimize the effort required to hold and align apertures inside the vacuum chamber, the apertures for the two lines of sight will be contained in the same array. In this work, we discuss the system requirements for neutron and γ-ray imaging and the resulting aperture array design.

A QTL study of cattle behavioral traits in embryo transfer families.

Two behavioral traits, temperament and habituation, were measured in 130 calves from 17 full-sib families which comprise the Canadian Beef Cattle Reference Herd. Using variance components, heritability was calculated as 0.36 for temperament and 0.46 for habituation. Genotyping of 162 microsatellites at approximately 20 cM intervals allowed the detection of six quantitative trait loci (QTL) for behavior traits on cattle chromosomes 1, 5, 9, 11, 14, 15.

Variability in vocal and behavioural responses to visual isolation between full-sibling families of beef calves.

In order to assess the value of vocal response as an indicator of welfare in cattle, it is necessary to investigate factors which influence vocal behaviour of individuals, that are independent of the specific environmental conditions to which they are exposed. The effect of parental differences, sex, age and weight on vocal responses of calves to visual isolation were examined. The relationship between vocal response and the amount of body movement during isolation were also evaluated.Seventeen full-sibling families of beef calves (N=130) were created by breeding five sires with 13 superovulated dams. Embryos were transferred into unrelated cows, which reared the calves to weaning age. Vocal response of calves and body movement were measured on four occasions, while they were visually isolated for 1min on a single animal scale platform. The first two observations were made on the day of weaning (mean age 166 days) and the following day. At the third and fourth observations their average ages were 278 and 350 days, respectively. On the four occasions 33.3, 34.8, 27.8 and 38.6% of calves, respectively, vocalized. Both sire and family had a significant influence on the number of vocalizations and acoustic properties of the sounds. Electronically-measured movement while on the scale was also influenced by sire and family, but there was no relationship between vocal responses and body movement. There was a tendency (P=0.08) for older and therefore heavier calves to produce longer vocalizations. In the final observing session, age and weight were positively correlated with fundamental frequency and the sound pressure level at the frequency of greatest intensity, and negatively correlated with the loudest harmonic. At the last two observations, significantly more heifer calves than bull calves vocalized. There was little difference between the acoustic properties of heifers' and bulls' vocalizations.The considerable individual variability in vocal response within a group of identically-treated calves is partly due to parental genetic influences that are independent of rearing and early experience. Other endogenous characteristics such as sex, age and weight also influence vocal response. But there is no clear relationship between individual temperament (as assessed by the amount of body movement during isolation) and characteristics of vocal response.