Abstract: A deuterium gas-puff load imploded by a multi-MA current driver, from a large initial diameter could be a powerful source of fusion neutrons, a plasma neutron source. Unlike the beam-target neutrons produced in Z-pinch plasmas in the 1950s and deuterium-fiber experiments in the 1980s, the neutrons generated in deuterium gas-puffs, with current levels achieved in recent experiments on the SNL Z facility, could contain a substantial fraction of thermonuclear origin. For recent deuterium gas-puff shots on Z, our analytical estimates and 1-D and 2-D simulations predict thermal neutron yields ~5 * 10(exp 13), in fair agreement with the yields measured on Z. It is demonstrated that the hypothesis of a beam-target origin of the observed fusion neutrons implies a very high Z-pinch-driver-to- fast-ions energy transfer efficiency. 5 to 10%, which would make a multi-MA deuterium Z-pinch the most efficient light-ion accelerator. No matter what mechanism is eventually determined to be responsible for generating fusion neutrons in deuterium gas-puff shots on Z, the neutron yield is shown to scale as Y(sub m) ~I(exp4 sub) where is I(sub m) is the peak current of the pinch. Theoretical estimates and numerical modeling of deuterium gas-puff implosions demonstrate that the yields of thermonuclear fusion neutrons that can be produced on ZR and the next generation machines are sufficiently high to make Plasma Neutron Sources (PNS) the most powerful, cost- and energy-efficient laboratory sources of 2.5 to 14MeV fusion neutron, just like Plasma Radiation Sources (PRS) are the most powerful sources of soft and keV x-rays. In particular, the predicted neutron-producing capability of PNS driven by ZR and ZX accelerators, from ~6 x 10(exp 16) to ~lO(exp 18) matches the projected capability of the NIF laser at thermonuclear energy gains of 1 and 20, respectively.
| Limitations: |
 APPROVED FOR PUBLIC RELEASE |
| Description: |
memorandum rept. 6 Jan-30 Sep 2005 |
| Pages: |
54 |
| Report Date: |
24 MAR 2006 |
| Contract Number: |
DEAC0494AL85000 |
| Report Number: |
A151644 |
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