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Noise equivalent counts are a convenient and effective means to assess PET emission image quality. We have extended the method to include the effects of transmission imaging on the statistics of attenuation corrected PET data. The result of the calculations is a noise figure which describes the SNR performance of the elements of the attenuation corrected emission sinogram. The noise figure demonstrates the tradeoff between emission and transmission imaging performance, and can be used to determine optimal partitioning of imaging time between emission and transmission scans. Also, the technique can be used to compare the efficacy of simultaneous transmission/emission imaging techniques and multiple orbiting rod source geometries. Experimental and simulated results from the GE 2048 PET scanner are used to demonstrate the model. In a sample imaging situation in that system geometry |0.2 |micro~Ci/cc activity in a 20-cm flood phantom, 3-mCi orbiting rod source(s)~, the dual rod source achieves 80 percent of the noise figure improvement which is available in simultaneous transmission/emission imaging without transmission data filtering, and demonstrates superior performance when a 3-point averaging transmission filter is applied.

Extreme ultraviolet (EUV) lithography requires nanostructured optical components, whose reliability can be influenced by radiation absorption and thermal conduction. Thermal conduction analysis is complicated by sub-continuum electron and phonon transport and the lack of thermal property data. This paper measures and interprets thermal property data, and their evolution due to heating exposure, for Mo/Si EUV mirrors with 6.9 nm period and Mo/Si thickness ratios of 0.4/0.6 and 0.6/0.4. We use time-domain thermoreflectance and the 3ω method to estimate the thermal resistance between the Ru capping layer and the Mo/Si multilayers (RRu-Mo/Si = 1.5 m2 K GW-1), as well as the out-of-plane thermal conductivity (kMo/Si 1.1 W m-1 K-1) and thermal anisotropy (η = 13). This work also reports the impact of annealing on thermal conduction in a co-deposited MoSi2 layer, increasing the thermal conductivity from 1.7 W m-1 K-1 in the amorphous phase to 2.8 W m-1 K-1 in the crystalline phase. [ABSTRACT FROM AUTHOR]