Lawson criterion for ignition exceeded in an inertial fusion experiment

For more than half a century, researchers around the world have been engaged in attempts to achieve fusion ignition as a proof of principle of various fusion concepts. Following the Lawson criterion, an ignited plasma is one where the fusion heating power is high enough to overcome all the physical processes that cool the fusion plasma, creating a positive thermodynamic feedback loop with rapidly increasing temperature. In inertially confined fusion, ignition is a state where the fusion plasma can begin "burn propagation" into surrounding cold fuel, enabling the possibility of high energy gain. While "scientific breakeven" (i.e., unity target gain) has not yet been achieved (here target gain is 0.72, 1.37 MJ of fusion for 1.92 MJ of laser energy), this Letter reports the first controlled fusion experiment, using laser indirect drive, on the National Ignition Facility to produce capsule gain (here 5.8) and reach ignition by nine different formulations of the Lawson criterion

Development of a tool for cavity failure compensation in superconducting linacs: progress and comparative study

International audienceReliability in high power hadron accelerators is a major issue, in particular for Accelerator-Driven Systems (ADS). In these devices, thermal fluctuations in the fission reactor must be avoided. A significant number of breakdowns are caused by the failure of accelerating cavities or by their associated systems. The cavities neighboring a fault can be retuned to compensate it and avoid extended beam interruptions. In this paper, we use a fully automated tool called LightWin to find compensation settings for a set of errors in a section of the superconducting linac of the Japan Atomic Energy Agency ADS project. LightWin models longitudinal beam dynamics, and does not take space charge effects into account. Hence, we inject LightWin compensation settings into TraceWin to perform multiparticle simulations. We compare the resulting beam optics to those found in a previous study with TraceWin only. We find that they are similar

Development of a tool for cavity failure compensation in superconducting linacs: progress and comparative study

International audienceReliability in high power hadron accelerators is a major issue, in particular for Accelerator-Driven Systems (ADS). In these devices, thermal fluctuations in the fission reactor must be avoided. A significant number of breakdowns are caused by the failure of accelerating cavities or by their associated systems. The cavities neighboring a fault can be retuned to compensate it and avoid extended beam interruptions. In this paper, we use a fully automated tool called LightWin to find compensation settings for a set of errors in a section of the superconducting linac of the Japan Atomic Energy Agency ADS project. LightWin models longitudinal beam dynamics, and does not take space charge effects into account. Hence, we inject LightWin compensation settings into TraceWin to perform multiparticle simulations. We compare the resulting beam optics to those found in a previous study with TraceWin only. We find that they are similar

Beam optics design of the superconducting region of the JAEA ADS

Abstract The Japan Atomic Energy Agency (JAEA) is proposing an Accelerator Driven Subcritical System (ADS) for the transmutation of the nuclear waste. ADS will consist of a superconducting CW proton linear accelerator of 30 MW and a subcritical nuclear reactor core. The main part of the acceleration will take part in the superconducting region using five types of radio frequency cavities. The ADS operation demands a high intensity and reliability of the beam. Therefore, the beam optics design plays a fundamental role to reduce the beam loss, control emittance growth and beam halo.</jats:p

Preliminary study of constraints, risks and failure scenarios for the High-Luminosity insertions at HL-LHC

TUPRO021International audienc

Electromagnetic design of the low beta cavities for the JAEA ADS

Abstract The Japan Atomic Energy Agency (JAEA) is designing a superconducting CW proton linear accelerator for the ADS project. The superconducting region will use five types of radio frequency cavities. In the region from 2 to 180 MeV the acceleration will be done using Half Wave Resonator (HWR) and Single Spokes (SS) cavities. HWR cavities will accelerate the beam from 2 to 10 MeV with a geometrical beta of 0.08 and the SS ones will do from 10 to 180 MeV using two cavity families with geometrical betas of 0.16 and 0.43. The results of electromagnetic model design are presented and the comparison with similar cavities from other projects are included.</jats:p

Design of the elliptical superconducting cavities for the JAEA ADS

Abstract The superconducting CW proton linear accelerator for an Accelerator Driven Subcritical System (ADS) proposed by Japan Atomic Energy Agency (JAEA) employs elliptical cavities for the final acceleration of 180 MeV to 1.5 GeV. Since this energy region implies a changed of β from 0.55 to 1, two cavity models were developed using the geometrical betas of 0.68 and 0.89 to improve the acceleration efficiency. The study of the electromagnetic design was simulated using SUPERFISH (SF) code and python program to do variable scan, the results were benchmarked with CST Microwave Studio program (CST).</jats:p

Electromagnetic design and characterization of an S-band 3-cell rf acceleration cavity

Abstract An S-Band (2998 MHz) Radio Frequency (RF) cavity to accelerate electrons was developed taking into account the beam space charge, the relativistic change in velocity of the low energy beam particle distribution through the cavity, and the emittance growth. The electromagnetic design and geometry optimization were done using the codes Poisson Superfish (PSF) and CST Studio (CST). In addition, beam dynamics simulations were done using the program Travel to optimize the emittance and take into account the space charge effect.</jats:p