Throughput maximization of queueing networks with simultaneous minimization of service rates and buffers The throughput of an acyclic, general-service time queueing network was optimized, and the total number of buffers and the overall service r ate w as reduced. To satisfy t hese conflicting objectives, a multiobjective genetic algorithm w as developed and employed. Thus, our method produced a set of efficient solutions f or more than one objective in t he objective f unction. A comprehensive set of computational experiments w as conducted to determine t he efficacy and efficiency of the proposed approach. Interesting insights obtained from the analysis of a complex network may assist practitioners in planning general-service queueing networks.

We describe the design and assembly of the LUX-ZEPLIN experiment, a direct detection search for cosmic WIMP dark matter particles. The centerpiece of the experiment is a large liquid xenon time projection chamber sensitive to low energy nuclear recoils. Rejection of backgrounds is enhanced by a Xe skin veto detector and by a liquid scintillator Outer Detector loaded with gadolinium for efficient neutron capture and tagging. LZ is located in the Davis Cavern at the 4850' level of the Sanford Underground Research Facility in Lead, South Dakota, USA. We describe the major subsystems of the experiment and its key design features and requirements.

LUX-ZEPLIN (LZ) is a second-generation direct dark matter experiment with spin-independent WIMPnucleon scattering sensitivity above 1.4 × 10−48 cm2 for a WIMP mass of 40 GeV/c2 and a 1000 days exposure. LZ achieves this sensitivity through a combination of a large 5.6 t fiducial volume, active inner and outer veto systems, and radio-pure construction using materials with inherently low radioactivity content. The LZ collaboration performed an extensive radioassay campaign over a period of six years to inform material selection for construction and provide an input to the experimental background model against which any possible signal excess may be evaluated. The campaign and its results are described in this paper.We present assays of dust and radon daughters depositing on the surface of components as well as cleanliness controls necessary to maintain background expectations through detector construction and assembly. Finally, examples from the campaign to highlight fixed contaminant radioassays for the LZ photomultiplier tubes, quality control and quality assurance procedures through fabrication, radon emanationmeasurements ofmajor sub-systems, and bespoke detector systems to assay scintillator are presented.