ARIES Documents -- Meetings ArchiveARIES Conference Call, 14 May, 2001
Documented by L. WaganerParticipants:
L. Waganer noted the date for the next ARIES meeting is June 7-8 with two full days of presentations at UCSD. Les Waganer suggested sending him tentative presentation titles to help prepare the draft meeting agenda.
John Sethian told the group that there is a laser IFE meeting at NRL on May 31-June 1. Any person interested in attending should call John for arrangements.
Chamber Wall Engineering
Don Haynes mentioned he received the HI threat spectrum from John Perkins. During the transcription process, some errors showed in the first few spectra bins. Don has corrected the data and he will transmit it to people who need the data. In addition, he is sending the data to Mark Tillack for installation on the ARIES Web site. Don is starting to evaluate the dry wall materials using the new HI threat spectrum. He was soliciting the first wall material candidates to be considered (e.g., C and W). Upon Rene Raffrayís return, he should be able to provide more definitive first wall material suggestions. Until then, C and W could be evaluated as the upper and lower bounds of likely materials.
Mark Tillack reported that Rene Raffray is in Europe. Mark said that Xueren Wang is looking at deposition and thermal response at the wetted wall surface. Mark said he was looking at evacuation of the dry wall chamber, conductance limits, gas kinetics and, the process of extracting the target debris from the xenon. Mark is developing the preliminary requirements for the wetted wall concept to be presented at the next meeting.
Chamber Nuclear Analysis
Laila El-Guebaly remarked that she has been looking at protection schemes for the laser final focus system by researching literature of other schemes to determine shielding options.
Drivers and Beam Transport
Simon Yu talked about beam transport options. He thought one of the open questions is the insulator required around the HI beam penetrations. This insulator prevents arcing from the beam to a near-by conductive surface. Les suggested silicon nitride as a ceramic insulator, but noting that the conductive target materials might condense onto these insulator surfaces and cause them to become conductive.
Simon Yu noted that Mission Research is assessing the self-pinch beam transport models to determine the possible pressure regimes for the pinch effect to work. The early results suggest a broad operating window might be possible. He said he might contact someone to present the results at the June meeting in Simonís absence.
Simon mentioned that at the beam transport workshop, a hose instability was discussed. Results to date indicate this instability might not be as serious as previously thought.
Phil Heitzenroeder told the group that PPPL has been investigating and analyzing the final focusing magnet system, working with Simon Yu and Leslie Bromberg (who is responsible for the magnet design.) Paul LaMarche is defining the vacuum system and Tom Brown is designing the magnet layout. Paul outlined his approach to pump the beamlines connected to the power chamber, which is maintained at 5 torr. Paul mentioned there are 124 beamlines with diameters of 3 cm. Simon noted that 124 beamlines converge into two physical penetrations into the chamber. Paul said he was considering using Roots blowers around 6000-liters/sec capacity. Base pressure in the beamlines is to be 10-5 to 10-4 torr. Les Waganer volunteered to provide some similar data from the Prometheus study to PPPL.
Tom Brown said that he had installed a layout of the final focus magnet on the ARIES Web site. Tom is adopting a modular approach for the magnet array with º of the magnets per module. Tom used the blowers Paul specified and determined there would be 20 per side for a total of 40 active pumps. Each pump would use two motors, ~100 hp for primary stage and ~30 hp for secondary stage. This would total to 4 MW of vacuum pump power for this design approach. It was suggested that a rotating mechanical shutter might reduce the pumping load by a factor of 10.
Target Fabrication, Injection, and Tracking
Ron Petzoldt mentioned that at the recent ID target meeting Mark Herrmann reported positive results about the high yield target. The surface roughness requirements could be relaxed and still achieve the desired performance. Ken Shultz affirmed the results were very positive for target fabrication capabilities. More details were requested and Ron said he would verify with Mark Herrmann if the results could be published on our web site. The attendees at the ID target meeting agreed to examine the range of possible materials with regard to manufacturing, safety, radiation effects, etc.
Ron reported that GA has coated mandrels with gold to measure argon and helium permeation with the following results.
Off Normal Event Assessment
Don Steiner said he has requested UCSD to provide data on the consequences of off normal shots on the all wall concepts. He is also working with INEEL to find technologies similar to that of targets to assess quality control on large production quantities of precise components. GA said that they are doing such assessments and would be willing to work with Don.
Ron Miller said that Wayne Meier provided a set of HI driver efficiencies to use in the ASC code. Ron noted that the provider of the software package he has been assessing has been sold, but the package is still being supported. He is continuing his assessment and plans a more thorough discussion at the next meeting.