Re: Neutron Scintillation Tube/Counter
Posted: Fri Dec 01, 2017 3:19 pm
Checked the fusor and the Earth quake did move my RF shielding screen over the DP throat; this is serious since it exposes all my gauge sensors to the high voltage plasma. Also, and maybe the cause of the current runaway my fusor experienced, the main viewing port/HV feed-thru was far too coated with metal (eroded, no doubt, from the electrode.) This might very well have created the conduction path leading to current run away by the fusor's power supply.
I disassembled the fusor's top and inspected the system. I removed and cleaned the main view port window. I re-assembled the fusor and placed it under vacuum. I have the DP heating up now.
I just tested the fusor at 50 microns and a stable plasma was easy to ignite and maintain a steady current (through very low voltage.) So far, what I am seeing makes sense for my theory of the main cause. Of course, until I test the fusor in full mode, can't know for sure.
I am including a picture of my new neutron detector's main system (less the detector tube, which is mounted on the fusor.)
The interface box is very simple but allows the high voltage from the digital supply to be put through a 100 M-ohm resistor, then this output has a voltage divider to monitor the net voltage that develops with the draw down by the detector tube (and even the ST-360); that is, this reduced output supplies the detector tube via another co-axial connector; then this detector line is fed into a simple resistor (to drop its voltage a good bit more (1/10)) allowing the detector's output signal (detector pulse) to reach the ST-360 to then be amplified and counted/displayed. All that interface box contains are a number of resistors, wires, and connections to various terminals located around the panels to be connected to the other devices. In some ways, that interface box is far too simple considering the issues its solves.
I disassembled the fusor's top and inspected the system. I removed and cleaned the main view port window. I re-assembled the fusor and placed it under vacuum. I have the DP heating up now.
I just tested the fusor at 50 microns and a stable plasma was easy to ignite and maintain a steady current (through very low voltage.) So far, what I am seeing makes sense for my theory of the main cause. Of course, until I test the fusor in full mode, can't know for sure.
I am including a picture of my new neutron detector's main system (less the detector tube, which is mounted on the fusor.)
The interface box is very simple but allows the high voltage from the digital supply to be put through a 100 M-ohm resistor, then this output has a voltage divider to monitor the net voltage that develops with the draw down by the detector tube (and even the ST-360); that is, this reduced output supplies the detector tube via another co-axial connector; then this detector line is fed into a simple resistor (to drop its voltage a good bit more (1/10)) allowing the detector's output signal (detector pulse) to reach the ST-360 to then be amplified and counted/displayed. All that interface box contains are a number of resistors, wires, and connections to various terminals located around the panels to be connected to the other devices. In some ways, that interface box is far too simple considering the issues its solves.