Conference Paper

Towards the Autonomous Operation of Z20: A TW Pulsed Power Module

Sandia Nat. Labs., Albuquerque, NM
DOI: 10.1109/PPC.2005.300533 Conference: Pulsed Power Conference, 2005 IEEE
Source: IEEE Xplore


The Refurbished Z machine, ZR, has 3 distinct missions. The first is to increase the capability for the user community by providing higher peak currents. The second is to increase the precision by increasing pulse repeatability and pulse shape flexibility. The third is to increase the capacity by providing operational turnaround time consistent with conducting a shot per shift. The pursuit of the third mission relies heavily on the reliability of the components and well defined maintenance cycles. To test the performance of the ZR design, a system assessment module has been tested and found to meet the capability mission. The system assessment module will be used to test the reliability of the components comprising the ZR pulsed power modules. To assess the program goal of 1 failure in 50 ZR shots we plan to perform 7200 shots of the system assessment module, Z20. At a typical shot rate, this task would take approximately three years. To minimize the impact on the facility while obtaining the required reliability data, the system will be configured to fire and reset autonomously with the ultimate goal of unmanned operation. A systems approach was developed using National Instruments Lab VIEWreg software and Field Point I/O hardware. All communications between subsystems are provided via ethernet using fiber optic media converters. The major subsystems for operating the module which will be described are the gas pressure and purge, high voltage power supplies, oil diverter operation, triggering, precision monitoring of Marx system, personnel access control and remote operation of the laser trigger system.

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Available from: Jane Lehr, Feb 15, 2015
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    ABSTRACT: An important consideration for the success of the ZR project, refurbishing the Z accelerator at Sandia National Laboratories, is limiting current loss in the vacuum section, ideally to no worse than the 5 – 10% seen on Z. The primary source for this loss is electrons flowing into the post-hole convolute from the four magnetically insulated transmission lines (MITLs). The MITLs on ZR have larger gaps to reduce the electron flow to values comparable to Z when operating at ∼40% higher voltage and ∼30% higher current. Electron flow in the vacuum section is analyzed with electromagnetic, particle-in-cell simulations, using two complementary simulation setups. First, the exact MITL profiles are modeled with high-resolution 2-D simulations out to large radius (typically r = 60 cm), providing accurate values for the electron flow into the convolute. Second, the convolute is modeled in 3-D, but with MITLs extending out only to r ∼ 30 cm. The 3-D MITL geometry is modified to provide the same electron flow into the convolute as the 2-D simulations. The 3-D simulations have detailed diagnostics for current loss and surface deposition heating in the convolute.
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