Proceedings of 16th International Symposium on Fusion Engineering
The Tokamak Physics Experiment (TPX) will use supercritical helium to cool all the magnets and su... more The Tokamak Physics Experiment (TPX) will use supercritical helium to cool all the magnets and supply helium
A twist reflector plate is described that linearly polarizes and focuses the TE Q1 CTrcu'lar wave... more A twist reflector plate is described that linearly polarizes and focuses the TE Q1 CTrcu'lar waveguide mode for heating net electrons in the thermal barrier of the Tandem Mirror Experiment-Upgrade (TMX-U). The plate polarizing efficiency is 95%, and it has operated satisfactorily at 150 kW power level. * Work performed under the auspices of the U. S. Department of Energy by the Lawrence Livermore National Laboratory UK-IP* -contract number W-7405-ENG-48.
Gated X-Ray imagers have been used on many ICF experiments around the world for time resolved ima... more Gated X-Ray imagers have been used on many ICF experiments around the world for time resolved imaging of the target implosions. DIXI (Dilation X-ray Imager) is a new fixed base diagnostic that has been developed for use in the National Ignition Facility. The DIXI diagnostic utilizes pulse-dilation technology and uses a high magnification pinhole imaging system to project images onto the instrument. DIXI is located outside the NIF target chamber approximately 6.5m from target chamber center (TCC). The pinholes are located 10cm from TCC and are aligned to the DIXI optical axis using a diagnostic instrument manipulator (DIM) on an adjacent port. By use of an extensive lead and poly shielded drawer enclosure DIXI is capable of collecting data at DT neutron yields up to Yn~ 10 16 on CCD readout and up to Yn~ 10 17 on film. Compared to existing pinhole x-ray framing cameras DIXI also provides a significant improvement in temporal resolution, <10ps, and the ability to capture a higher density of images due to the fact the pinhole array does not require collimators. The successful deployment of DIXI on the NIF required careful attention to the following subsystems, pinhole imaging, debris shielding, filtering and image plate (FIP), EMI protection, large format CsI photocathode design, detector head, detector head electronics, control electronics, CCD, film recording and neutron shielding. Here we discuss the initial design, improvements implemented after rigorous testing, infrastructure and commissioning of DIXI on the NIF.
Proceedings of International Conference on Particle Accelerators
We have used the improved ETA-II linear induction accelerator (ETA-III) and the IMP steady-state ... more We have used the improved ETA-II linear induction accelerator (ETA-III) and the IMP steady-state wiggler to generate high power (l-2 GW) microwaves at 140 GHz. The FEL was used in an amplifier configuration with a gyrotron driver. Improved control of energy sweep and computerized magnetic alignment in ETA-III resulted in small beam corkscrew motion (< 1.5 mm) at 6 Mcv, 2.5 kA. Reduction of wiggler errors (< 0.2%), improved electron beam matching, and tapered wiggler operation resulted in peak microwave power (single-pulse) of up to 2 GW. These pulses were transported to the MTX tokamak for microwave absorption experiments. In addition, the FEL was run in a burst mode, generating 50-pulse bursts of microwaves; these results are discussed elsewhere [l].
We describe the modeling, the experimental facility, and the initial operating results for ELF-II... more We describe the modeling, the experimental facility, and the initial operating results for ELF-II, an induction-linac based free-electron laser designed to produce up to 2 GW of peak power at 140 GHz. ELF-II is the initial configuration of a free electron laser (FEL) system which will eventually produce up to 2 MW of average power at a frequency of 250
The goal of the National Ignition Campaign at the National Ignition Facility is to obtain ignitio... more The goal of the National Ignition Campaign at the National Ignition Facility is to obtain ignition of an inertially confined fusion capsule. In this work, we describe the neutron imaging system that we are installing at the National Ignition Facility to provide information on the spatial distribution of material in the compressed capsule and any uncompressed fuel. The imager uses
The Intense Microwave Prototype (IMP) is an induction-linac based free-electron laser (IFEL) ampl... more The Intense Microwave Prototype (IMP) is an induction-linac based free-electron laser (IFEL) amplifier system that is presently under construction at the Lawrence Livermore National Laboratory (LLNL). It will produce up to 2 MW of average power at 250 GHz for electron cyclotron resonance heating experiments in the Microwave Tokamak Experiment (MTX). The Experimental Test Accelerator-II (ETA-II) will provide the electron beam. ETA-II is designed to produce an electron beam with a current of 3 kA at an energy of 10 MeV and a brightness of over 10⸠A/(m-rad)². In addition, it is designed to produce 70-ns-FWHM pulses at a repetition rate of 5 kHz. The high magnetic field and wide tunability capabilities required for the FEL will be provided by a permanent magnet-laced electromagnetic wiggler with a 10-cm period and an overall length of 5.5 m. We present the physics design and expected performance of the FEL, along with a description of the experiment and of the phased development to ...
This paper presents an idea for a magnet system that could be used to advantage in tokamaks and o... more This paper presents an idea for a magnet system that could be used to advantage in tokamaks and other fusion engineering devices. Higher performance designs, specifically newer tokamaks such as those for the International Thermonuclear Engineering Reactor (ITER) and Tokamak Physics Experiment (TPX), use cable-in-conduit conductor (CICC) forced-flow coils to meet field and current-density requirements. Pool-boiling magnets have limited structural integrity because helium cooling areas must surround each conductor. CICC magnets eliminate these disadvantages by using internal cooling. However, the CICC system introduces other disadvantages, in particular, there may be leaks in the sheath at an inaccessible location. The system proposed here is basically a CICC system, with it's inherent advantages, but bathed in supercritical helium to eliminate the leak and voltage breakdown problems. Schemes to simplify helium-coolant plumbing with the proposed system are discussed. The advantag...
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 1990
We describe the modeling, the experimental facility, and the initial operating results for ELF-II... more We describe the modeling, the experimental facility, and the initial operating results for ELF-II, an induction-linac based free-electron laser designed to produce up to 2 GW of peak power at 140 GHz. ELF-II is the initial configuration of an FEL system which will eventually produce up to 2 MW of average power at a frequency of 250 GHz, for use in plasma heating experiments in the Microwave Tokamak Experiment. 6 refs., 9 figs.
Proceedings of 16th International Symposium on Fusion Engineering
The Tokamak Physics Experiment (TPX) will use supercritical helium to cool all the magnets and su... more The Tokamak Physics Experiment (TPX) will use supercritical helium to cool all the magnets and supply helium
A twist reflector plate is described that linearly polarizes and focuses the TE Q1 CTrcu'lar wave... more A twist reflector plate is described that linearly polarizes and focuses the TE Q1 CTrcu'lar waveguide mode for heating net electrons in the thermal barrier of the Tandem Mirror Experiment-Upgrade (TMX-U). The plate polarizing efficiency is 95%, and it has operated satisfactorily at 150 kW power level. * Work performed under the auspices of the U. S. Department of Energy by the Lawrence Livermore National Laboratory UK-IP* -contract number W-7405-ENG-48.
Gated X-Ray imagers have been used on many ICF experiments around the world for time resolved ima... more Gated X-Ray imagers have been used on many ICF experiments around the world for time resolved imaging of the target implosions. DIXI (Dilation X-ray Imager) is a new fixed base diagnostic that has been developed for use in the National Ignition Facility. The DIXI diagnostic utilizes pulse-dilation technology and uses a high magnification pinhole imaging system to project images onto the instrument. DIXI is located outside the NIF target chamber approximately 6.5m from target chamber center (TCC). The pinholes are located 10cm from TCC and are aligned to the DIXI optical axis using a diagnostic instrument manipulator (DIM) on an adjacent port. By use of an extensive lead and poly shielded drawer enclosure DIXI is capable of collecting data at DT neutron yields up to Yn~ 10 16 on CCD readout and up to Yn~ 10 17 on film. Compared to existing pinhole x-ray framing cameras DIXI also provides a significant improvement in temporal resolution, <10ps, and the ability to capture a higher density of images due to the fact the pinhole array does not require collimators. The successful deployment of DIXI on the NIF required careful attention to the following subsystems, pinhole imaging, debris shielding, filtering and image plate (FIP), EMI protection, large format CsI photocathode design, detector head, detector head electronics, control electronics, CCD, film recording and neutron shielding. Here we discuss the initial design, improvements implemented after rigorous testing, infrastructure and commissioning of DIXI on the NIF.
Proceedings of International Conference on Particle Accelerators
We have used the improved ETA-II linear induction accelerator (ETA-III) and the IMP steady-state ... more We have used the improved ETA-II linear induction accelerator (ETA-III) and the IMP steady-state wiggler to generate high power (l-2 GW) microwaves at 140 GHz. The FEL was used in an amplifier configuration with a gyrotron driver. Improved control of energy sweep and computerized magnetic alignment in ETA-III resulted in small beam corkscrew motion (< 1.5 mm) at 6 Mcv, 2.5 kA. Reduction of wiggler errors (< 0.2%), improved electron beam matching, and tapered wiggler operation resulted in peak microwave power (single-pulse) of up to 2 GW. These pulses were transported to the MTX tokamak for microwave absorption experiments. In addition, the FEL was run in a burst mode, generating 50-pulse bursts of microwaves; these results are discussed elsewhere [l].
We describe the modeling, the experimental facility, and the initial operating results for ELF-II... more We describe the modeling, the experimental facility, and the initial operating results for ELF-II, an induction-linac based free-electron laser designed to produce up to 2 GW of peak power at 140 GHz. ELF-II is the initial configuration of a free electron laser (FEL) system which will eventually produce up to 2 MW of average power at a frequency of 250
The goal of the National Ignition Campaign at the National Ignition Facility is to obtain ignitio... more The goal of the National Ignition Campaign at the National Ignition Facility is to obtain ignition of an inertially confined fusion capsule. In this work, we describe the neutron imaging system that we are installing at the National Ignition Facility to provide information on the spatial distribution of material in the compressed capsule and any uncompressed fuel. The imager uses
The Intense Microwave Prototype (IMP) is an induction-linac based free-electron laser (IFEL) ampl... more The Intense Microwave Prototype (IMP) is an induction-linac based free-electron laser (IFEL) amplifier system that is presently under construction at the Lawrence Livermore National Laboratory (LLNL). It will produce up to 2 MW of average power at 250 GHz for electron cyclotron resonance heating experiments in the Microwave Tokamak Experiment (MTX). The Experimental Test Accelerator-II (ETA-II) will provide the electron beam. ETA-II is designed to produce an electron beam with a current of 3 kA at an energy of 10 MeV and a brightness of over 10⸠A/(m-rad)². In addition, it is designed to produce 70-ns-FWHM pulses at a repetition rate of 5 kHz. The high magnetic field and wide tunability capabilities required for the FEL will be provided by a permanent magnet-laced electromagnetic wiggler with a 10-cm period and an overall length of 5.5 m. We present the physics design and expected performance of the FEL, along with a description of the experiment and of the phased development to ...
This paper presents an idea for a magnet system that could be used to advantage in tokamaks and o... more This paper presents an idea for a magnet system that could be used to advantage in tokamaks and other fusion engineering devices. Higher performance designs, specifically newer tokamaks such as those for the International Thermonuclear Engineering Reactor (ITER) and Tokamak Physics Experiment (TPX), use cable-in-conduit conductor (CICC) forced-flow coils to meet field and current-density requirements. Pool-boiling magnets have limited structural integrity because helium cooling areas must surround each conductor. CICC magnets eliminate these disadvantages by using internal cooling. However, the CICC system introduces other disadvantages, in particular, there may be leaks in the sheath at an inaccessible location. The system proposed here is basically a CICC system, with it's inherent advantages, but bathed in supercritical helium to eliminate the leak and voltage breakdown problems. Schemes to simplify helium-coolant plumbing with the proposed system are discussed. The advantag...
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 1990
We describe the modeling, the experimental facility, and the initial operating results for ELF-II... more We describe the modeling, the experimental facility, and the initial operating results for ELF-II, an induction-linac based free-electron laser designed to produce up to 2 GW of peak power at 140 GHz. ELF-II is the initial configuration of an FEL system which will eventually produce up to 2 MW of average power at a frequency of 250 GHz, for use in plasma heating experiments in the Microwave Tokamak Experiment. 6 refs., 9 figs.
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