Ambitious subsidy reform by the WTO presents opportunities for ocean health restoration

This is the author accepted manuscript. The final version is available from Springer via the DOI in this recordThe World Trade Organization (WTO) is in a unique position to deliver on Sustainable Development Goal (SDG) 14.6 by reforming global fisheries subsidies in 2020. Yet, a number of unanswered questions threaten to inhibit WTO delegates from crafting a smart agreement that improves global fisheries health. We combine global data on industrial fishing activity, subsidies, and stock assessments to show that: (1) subsidies prop up fishing effort all across the world’s ocean and (2) larger subsidies tend to occur in fisheries that are poorly managed. When combined, this evidence suggests that subsidy reform could have geographically-extensive consequences for many of the world’s largest fisheries. While much work remains to establish causality and make quantitative predictions, this evidence informs the rapidly-evolving policy debate and we conclude with actionable policy suggestions.Pew Charitable Trust

Recent Developments in the Design of the NLC Positron Source

Recent developments in the design of the Next Linear Collider (NLC) positron source based on updated beam parameters are described. The unpolarized NLC positron source [1,2] consists of a dedicated 6.2 GeV S-band electron accelerator, a high-Z positron production target, a capture system and an L-band positron linac. The 1998 failure of the SLC target, which is currently under investigation, may lead to a variation of the target design. Progress towards a polarized positron source is also presented. A moderately polarized positron beam colliding with a highly polarized electron beam results in an effective polarization large enough to explore new physics at NLC. One of the schemes towards a polarized positron source incorporates a polarized electron source, a 50 MeV electron accelerator, a thin target for positron production and a new capture system optimized for high-energy, small angular-divergence positrons. The yield for such a process, checked using the EGS4 code, is of the order of 10{sup -3}. The EGS4 code has being enhanced to include the effect of polarization in bremsstrahlung and pair-production process

The NLC Injector System

The Next Linear Collider (NW) Injector System is designed to produce low emittance, 10 GeV electron and positron beams at 120 hertz for injection into the NLC main linacs. Each beam consists of a train of 9.5 bunches spaced by 2.8 ns; each bunch has a population of 1.15 x 10{sup 10} particles. At injection into the main linacs, the horizontal and vertical emittances are specified to be {gamma}{var_epsilon}{sub x} = 3 x 10{sup -6} m-rad and {gamma}{var_epsilon}{sub y} = 3 x 10{sup -8} m-rad and the bunch length is 100 {micro}m. Electron polarization of greater than 80% is required. Electron and positron beams are generated in separate accelerator complexes each of which contain the source, damping ring systems, L-band, S-band, and X-band linacs, bunch length compressors, and collimation regions. The need for low technical risk, reliable injector subsystems is a major consideration in the design effort. This paper presents an overview of the NLC injector systems

THE NEXT LINEAR COLLIDER DAMPING RING COMPLEX ∗

We report progress on the design of the Next Linear Collider (NLC) Damping Rings complex (DRC) [1]. The purpose of the DRC is to provide 120 Hz, low emittance electron and positron bunch trains to the NLC linacs [2]. It consists of two 1.98 GeV main damping rings, one positron pre-damping ring, two pairs of bunch length and energy compressor systems and interconnecting transport lines. The 2 main damping rings store up to 0.8 amp in 3 trains of 95 bunches each and have normalized extracted beam emittances γεx = 3 μm-rad and γεy = 0.03 μm-rad. The preliminary optical design, performance specifications and tolerances are given in [1]. Key subsystems include 1) the 714 MHz RF system [3], 2) the 60 ns risetime injection / extraction pulsed kicker magnets [4], 3) the 44 m wiggler magnet system, 4) the arc and wiggler vacuum system, 5) the radiation management system, 6) the beam diagnostic instrumentation, 7) special systems used for downstream machine protection and 8) feedback-based stabilization systems. Experience at the SLAC Linear Collider has shown that the NLC damping rings will have a pivotal role in the operation of the high power linacs. The ring dynamics and instabilities will in part determine the design choices made for the NLC machine protection system. This paper includes a summary overview of the main ring design and key subsystem components.