High School Fusor: First Light of Fusor 1!

Fusor 1.1 Design:

The design for Fusor 1.1 (named as such to differentiate it from the many Fusor 0 designs) is very basic and follows many of the principles advocated for on fusor.net.

A top-down view of the chamber.
The setup that I used for my “bulkhead” test of the HVAC vacuum pump. The PVC hose runs to a barbed connector attached to the vacuum pump NPT inlet.
The tantalum grid inside the chamber during first assembly. The grid has since been slid up on the stalk to better center it within the chamber.
Fusor 1.1, set up for the first test
Me with Fusor 1.1

Test 1:

I achieved first light of Fusor 1.1 on November 14 at 11:14 AM (a little bit of serendipity there). From first activating the pump to re-pressurizing the chamber, the test took about than 30 minutes overall with plasma being generated for approximately 8 of those minutes.

Procedure:

  1. All metering activated and confirmed to be at ambient levels
  2. Vacuum pump activated
  3. Upon reaching below 700 microns of pressure within the chamber, the variac is switched on
  4. Variac dial turned up at intervals of 10 volts (measured on the multimeter), plasma within chamber is observed between turning up the variac
  5. At some point, variac turned to 0V and is switched off. As a precaution, if pressure within the chamber ever increases above 2000 microns, the variac is immediately switched off
  6. Vacuum pump switched off
  7. Immediately after the pump is switched off, the KF-25 thermocouple connection clamp is removed and the vacuum seal is broken, repressurizing the chamber (this is done to prevent oil back-flow into the chamber from the vacuum pump)

Results:

Outstanding Success! Plasma was generated within the chamber at various NST input voltages and chamber pressures!

The first instant of successful plasma within the Fusor 1 chamber. Metering: 369Vdc at 1.1mA (0.41W) at approx. 650 microns. 10.3Vac NST input
396Vdc at 5.6mA (2.22W) at approx. 775 microns. 20.8Vac NST input.
473V at 9.3mA (4.40W) at approx. 900 microns. 29.8Vac NST input
500Vdc at 14.5mA (7.25W) at approx. 1000 microns. 40.0Vac NST input
575Vdc at 19.6mA (11.27W) at approx. 975 microns. 50.7Vac NST input
In table form,
and in graph form!

Analysis:

There are two primary differences between Fusors 0 and 1:

Fusor 0 Comparison:

Comparing the Fusor 0 and Fusor 1 data, these differences in chamber design have clearly had an effect upon the system:

742Vdc at 0.0 mA (0W). Pressure Unknown. 11.3Vac NST Input
369Vdc at 1.1mA (0.41W) at approx. 650 microns. 10.3Vac NST input
575Vdc at 3.6mA (2.07W). Pressure Unknown. 20.1Vac NST Input
396Vdc at 5.6mA (2.22W) at approx. 775 microns. 20.8Vac NST input.
556Vdc at 8.6mA (4.78W). Pressure Unknown. 30.0Vac NST Input.
473V at 9.3mA (4.40W) at approx. 900 microns. 29.8Vac NST input
564Vac at 13.5mA (7.61W). Pressure Unknown. 39.9Vac NST Input.
500Vdc at 14.5mA (7.25W) at approx. 1000 microns. 40.0Vac NST Input
559Vac at 19.6mA (10.96W). Pressure Unknown. 50.4Vac NST Input.
575Vdc at 19.6mA (11.27W) at approx. 975 microns. 50.7Vac NST input
562Vdc at 25.4mA (14.27W). Pressure Unknown. 60.4Vac NST Input
582Vdc at 31.2mA (18.16W). Pressure Unknown. 70.3Vac NST Input
594Vdc at 37.3mA (22.16W). Pressure Unknown. 80.0Vac NST Input
619Vdc at 44.1mA (27.30W). Pressure Unknown. 90.5Vac NST Input
632Vdc at 52.2mA (32.99W). Pressure Unknown. 100.8Vac NST Input
650Vdc at 51.6mA (33.54W). Pressure Unknown. 110.1Vac NST Input
671Vdc at 69.9mA (46.90W). Pressure Unknown. 120.1Vac NST Input
665Vac at 93.4mA (62.11W). Pressure Unknown. 138.4Vac NST Input

Next Steps:

I have already conducted another Fusor 1.1 test that I have not discussed here in the interest of keeping this post somewhat focused. That test has raised many questions that I am going to attempt to answer in the near future and will discuss in another post.

Notes & Citations:

¹ https://www.fusor.net/board/viewtopic.php?f=29&t=4266

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Maxwell Epstein

Maxwell Epstein

Hey! My name is Max and I’m a high school senior! This blog is where I will document my progress designing and building a Farnsworth-Hirsch IEC nuclear fusor :)