Fusion Message Board

In this space, visitors are invited to post any comments, questions, or skeptical observations about Philo T. Farnsworth's contributions to the field of Nuclear Fusion research.

Subject: Re: Pulsing an IEC 1,2,3 BANG!!!!
Date: Oct 13, 1:13 pm
Poster: Jim Lux

On Oct 13, 1:13 pm, Jim Lux wrote:

Another paper of interest would be:

"Pulsed IEC Neutron Generator" by Yibin Gu, George Miley, and Susan DelMedico, in an IEEE conference proceedings

They describe an experimental setup using a 2 uF capacitor, charged through a 50 k resistor. The shunt resistor is 100-400K, and a discharge resistor of 550 Ohms is connected using a HY1102 thyratron, triggered by a SCR/cap circuit using an optocoupled circuit. Looks like they used battery power to heat the cathode, and ran the pulse current through the thyratron grid.

The voltages were quite low (10 kV), and they got around 3000 neutrons per pulse at 100 mA average pulse current (the pulse width looks like about 20 mSec to 50%) (I hate it when they don't put a vertical scale on the scope traces (probably because they didn't actually calibrate it)).. The neutron rate goes as I^2 at this voltage

at 15 kV, they were getting 8000 neuts at an average current of 50 mA, with a I^1.3 scaling.

An interesting comment is that the scaling is better at lower voltages because the ions are moving slower, and so remain in the central area longer. Seems the idea is to get them going just fast enough to fuse, then make bunches of them.
A perveance threshold of 2.2 mA/(kV^1.5) is theorized..

They go on to theorize that at 100 kV, a pulsed current of 2A would be required to achieve a double well (I^2 scaling).. interesting comment "modification of the internal grid structure to prevent arcing at the higher voltages.
At this kind of power, they expect neutron yields 4 orders of magnitude greater than the steady state 1E6/second of the current device (15 mA, 70 kV). (10% duty cycle). Are they serious? 1E10 n/sec as bursts of 1E11 n/sec?

Their fusor is 30 cm vacuum vessel size