Now showing 1 - 5 of 5
  • Publication
    The effect of viewing angle on the spectral behavior of a Gd plasma source near 6.7 nm
    We have demonstrated the effect of viewing angle on the extreme ultraviolet (EUV) emission spectra of gadolinium (Gd) near 6.7 nm. The spectra are shown to have a strong dependence on viewing angle when produced with a laser pulse duration of 10 ns, which may be attributed to absorption by low ion stages of Gd and an angular variation in the ion distribution. Absorption effects are less pronounced at a 150-ps pulse duration due to reduced opacity resulting from plasma expansion. Thus for evaluating source intensity it is necessary to allow for variation with both viewing angle and target orientation.
      549Scopus© Citations 18
  • Publication
    High rates of regular soil testing by Irish dairy farmers but nationally soil fertility is declining: Factors influencing national and voluntary adoption
    (Institute of Agricultural Management, 2016-12-01) ; ; ;
    Paradoxically, high rates of soil testing by Irish dairy farmers coexist with declining national soil fertility levels. This study investigates the anomaly further through identifying the characteristics of farms and farmers who regularly test soil in terms of policy, education, financial capacity, networks, and land management practices. The study draws on data from a nationally representative sample of 231 specialist Irish dairy holdings. As policy mandates the use of soil tests for some farmers, a sub-sample of nonmandated farms is analysed separately. Findings comparing testers and non-testers show all farmers testing their soil on a regular basis are younger, have larger farms and herds, have larger gross output, have greater expenditure on nitrogen, and are more profitable, compared to farmers who do not. The analysis also shows nationally there is no significant difference in fertilizer and concentrate expenditure per hectare between soil test users and non-users, also reflected in the sub-sample. The logit regression analysis of the full sample suggests policy and extension programmes have a significant effect on adoption, however given national falling soil fertility trends farmers may not be using the results to achieve optimal outcomes. For the voluntary sub-sample farmers who attended part-time education courses and improved farmland through reseeding are more likely to regularly soil test. These findings are important in the context of the somewhat contradictory environmentally-focused and productivity-focused policy instruments that drive regular soil testing behaviour and the anomaly of high rates of soil testing with declining national soil fertility levels.
  • Publication
    Proven Science versus Farmer Perception
    (International Conference of Agricultural Economists, 2015-08-14) ; ; ;
    Resource use efficiency is at the core of sustainable farming practices for the future of agriculture. Given the abolition of quotas in the EU and the increasing demands for food globally food producers are faced with a challenge to increase production in an environmentally sustainable manner. This paper examines the adoption of a suite of grassland management practices by Irish dairy farmers which are proven to improved grass utilisation. The Technology Acceptance Model is applied to a nationally representative sample of specialist Irish dairy farmers to investigate the use of belief based variables and traditional socioeconomic and demographic variables in predicting intention to use six grassland management practices.
  • Publication
    Scaling of laser produced plasma UTA emission down to 3 nm for next generation lithography and short wavelength imaging
    An engineering prototype high average power 13.5-nm source has been shipped to semiconductor facilities to permit the commencement of high volume production at a 100 W power level in 2011. In this source, UTA (unresolved transition array) emission of highly ionized Sn is optimized for high conversion efficiency and full recovery of the injected fuel is realized through ion deflection in a magnetic field. By use of a low-density target, satellite emission is suppressed and full ionization attained with short pulse CO2 laser irradiation. The UTA is scalable to shorter wavelengths, and Gd is shown to have similar conversion efficiency to Sn (13.5 nm) at a higher plasma temperature, with a narrow spectrum centered at 6.7 nm, where a 70% reflectivity mirror is anticipated. Optimization of short pulse CO2 laser irradiation is studied, and further extension of the same method is discussed, to realize 100 W average power down to a wavelength of 3 nm
    Scopus© Citations 9  652
  • Publication
    Optimizing conversion efficiency and reducing ion energy in a laser-produced Gd plasma
    We have demonstrated an efficient extreme ultraviolet (EUV) source at 6.7 nm by irradiating Gd targets with 0.8 and 1.06 μm laser pulses of 140 fs to 10 ns duration. Maximum conversion efficiency of 0.4% was observed within a 0.6% bandwidth. A Faraday cup observed ion yield and time of flight signals for ions from plasmas generated by each laser. Ion kinetic energy was lower for shorter pulse durations, which yielded higher electron temperatures required for efficient EUV emission, due to higher laser intensity. Picosecond laser pulses were found to be the best suited to 6.7 nm EUV source generation.
      694Scopus© Citations 44