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Star Mode and More!

Posted: Thu Jul 30, 2015 10:58 pm
by Jack Rosky
Hello All!,
The past couple of weeks Scott and I have been very busy at NJIT working towards fusion. Within these weeks we have made great progress and have decided to make an update.
First,
We have finalized our designs for our future chamber and experiments and got the CAD done for them. Our new chamber is 9" inner diameter and is mounted on 12" conflat fittings. Our chamber will include room for a 4.5" lead view port and a rotary feed through, needed for our future experiment. This chamber is in process of being fabricated and we will be receiving it shortly so we can begin our experiment design and start data acquisition.
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CAD for our new Chamber
Second,
Scott and I were very pleased to have been kindly donated a MFC calibrated for D2 which we got in the mail yesterday. This will be rather crucial for maintaining our flow rate for our experiment.

Third,
We have constructed the controller for our 40kv Glassman HVPS (it still has a few kinks, but they are being worked out) and we fired it up today, allowing us to get plasma at lower and lower pressure and get to higher and higher voltages. With this new HVPS we have finally achieved "Star Mode" with 4 distinct beams and 2 fainter ones. In the picture you can also see the scintillations from the x-rays shining through the glass viewport(you may need to click to enlarge the image to notice them). We could not get an exact reading of these x-rays, but my Geiger counter was displaying reading in the hundreds of thousands of CPMs. This image was taken at around 35kv and 30mTorr of pressure. We are working on getting a current read out soon.
IMG_0754[1].JPG
Star Mode
Below in the image you can see the marks made by the star mode beams hitting the inside of our chamber walls. We took this picture as we were replacing our stainless steel grid with a new hafnium grid, which will hopefully withstand the heat a bit better.
IMG_0756[1].JPG
Burn marks from where the starmode beams hit
Thanks for reading! Everyday Scott and I get closer to fusion. All that is left is attach the deuterium gas system and set up our diffusion pump and water cooling system for it.
-Jack Rosky

Re: Star Mode and More!

Posted: Fri Jul 31, 2015 9:16 am
by Dennis P Brown
Congratulations! Outstanding work and great pictures! I understand the issue of measuring current, as well. Best of luck and hope to see you make the neutron club. Glad you mentioned the X-ray issue; I too need to check that on mine when I replace the main window ...

Re: Star Mode and More!

Posted: Fri Jul 31, 2015 9:19 am
by Dennis P Brown
Dennis P Brown wrote:Congratulations! Outstanding work and great pictures! I understand the issue of measuring current, as well. Best of luck and hope to see you make the neutron club. Glad you mentioned the X-ray issue - forgot about that; I too need to check that hazard on mine when I replace the main window ...

Re: Star Mode and More!

Posted: Fri Aug 14, 2015 4:32 am
by Scott Moroch
Over the last couple of weeks Jack and I have been making very steady progress. We have installed our diffusion pump into our system with the oil. With the hose clamps and the ASA fitting we have been able to achieve the same pressure as we were without the diffusion pump installed. We have installed our entire deuterium gas system which consists of a 10 liter lecture bottle of D2, a gas regulator, a ball valve and a swagelok ss-ss4 needle valve. Over the last couple of days we have been primairly focused on passing inspections from the safety department and the radiation consultant. Despite the low risk of neutron emission, we had to prove that the neutrons would not pose a risk and that distance from the fusor is the best shielding. As far as x rays are concerned, we may be shielding the entire chamber with lead sheeting in order to be allowed to use the viewport. We are currently about 1-2 weeks away from achieving fusion. There are a few minor things we still need to finish::

1) Lead sheeting around the chamber
2) A water cooling system for the diffusion pump- a two pump design has already been planned and the pumps should be arriving by tomorrow
3) A new ballast resistor after I accidently dropped the last one. I have several in my basement that arrived today and need to be tested (40k ohm at 200watt, 60k ohm 200 watt, 75k ohm 160 watt)
4) A small fence to be placed at a distance of 1 meter radially from the fusor. Through our calculations we proved that the dosage at 1 meter is immeasurable. This fence is not meant to physically prevent us from getting close to the fusor, rather to let everyone else in the lab know that the fusor is operating and high voltage is applied.

I will attach some images of our latest progress. Our neutron detection system is also fully prepared with our 3He probe and Eberline PNC-1. In addition, a very special thanks to Jake Hecla, Ben Bartlett, Richard Hull, Jim Kovalchick, and Tim Koeth who wrote emails, provided data, and ran simulations and calculations to help us prove to the safety department that the x rays from the fusor can easily be shielded and that the neutron dosage is very low.