First Neutrons from San Diego

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Nick Peskosky
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Real name: Nicholas Peskosky
Location: San Diego, CA

First Neutrons from San Diego

Post by Nick Peskosky » Sun Jan 11, 2015 2:35 am

All,

It has taken a little over two years since I first began reactor construction but I think I've finally realized D-D fusion. I believe to have statistically significant enough data to petition for entrance into the Neutron club, including both data taken before/during/post fusion run and an accompanying video demonstrating thermalized neutron detection on my He-3 detector.

First a quick synopsis of my current setup:

My Fusor is based around a 6" Conflat Tee which has an additional 2.75" port and male 1/4" VCR connection. The chamber has a 2.75" viewport on the left reducing flange and the port is shielded with material from an X-ray apron and a Victoreen 1.5mm Pb equivalent plastic block. The chamber containing the tungsten-tantalum alloy grid is connected through various reducers and CF hardware to an Alcatel 5150 turbomolecular pump which is backed by an Alcatel 2021i 2-stage rotary pump. Pressure is measured on the high vacuum side by an INFICON BPG400 combination Pirani/Bayard-Alpert ion gauge and on the roughing side by a INFICON TPG500 Pirani gauge (both gauges feed their analog voltage outputs to an Arduino which uses a LUT of manufacturer supplied equations to calculate and display the current pressure). I have shelved the Kaiser Systems LS1500 which was utilized for my first light HV and power is now supplied to the grid by a Glassman EW30R20.0-11 rack mount HVDC power supply. Deuterium gas is produced by the same PEM fuel cell/electrolyzer heavy water method many others on this board have demonstrated in the past. Gas is collected in a 150mL boiling flask over vacuum pump oil and fed through various 1/4" hardware including a Nupro SS4-BK valve and Granville Phillips Series 203 precision leak valve prior to admission to the reactor chamber. An older revision of my work can be seen in the link below:

viewtopic.php?f=6&t=8886&hilit=reactor+first+light

Neutron Metrology:

A Helium-3 proportional tube serves as my primary means of neutron detection. The tube itself is a RS-P4-0808-214, it contains a 4 atm He-3 fill and has an active area of approximately 8.0". Moderation is provided by a block of HDPE (sourced from kitchen cutting boards) with a 1.125" diameter cylindrical void which the tube can readily be inserted and removed from. The detector is connected via HN connector to a Tennelec TC-175 charge sensitive pre-amplifier. Pulse output from the pre-amp is then fed to a CI 6000 NIM rack containing the following BINs:

Prinecton Gamma-Tech Model 315A 5kV Bias Supply (current Vbias ~1600V)
Model 7039 Spectroscopy Amplifier (16X Gain) + fed to BNC-to-3.5mm adapter for PRA sampling by laptop
Canberra 2030 SCA
Ortec 773 Timer Counter
CI Model 1481 Rate Meter

The average background count for my garage is approximately 2.8 CPM from cosmic events and environmental neutrons. The tube's operation was confirmed with aid of Bruce Meagher's Po-Be spallation source. During fusion runs the center of the detector is located ~18 cm from the poissor.

D-D Fusor Runs:

Data for the runs I conducted last night are in the attached spreadsheet. Neutron counts last night spanned from 59.1-328.8 CPM (over various voltage and current levels) while pressure remained constant at 8.5-9.5 Microns (pressures displayed on my serial lcd display are not calibrated for deuterium gas C=0.78). I follow the below procedure when running the system:

1. Backing pump is turned on
2. Open KF bellows valve on outlet of turbo and open CF bellows throttling valve (foreline/chamber pressure are allowed to hit at least <20 micron)
3. CFF 450 controller is turned on and turbomolecular pump is allowed to ramp
4. The D2 generator is allowed to run while the chamber is pumped down to the low E-5Torr range (usually 10-15 minutes)
5. The gas feed line is closed at the diaphragm valve and vacuumed through the leak valve, leak valve is then closed
6. Throttling valve is set 1/3 turn from closed
7. D2 gas is leaked through the SS4-BK valve until sight gauge shows atmospheric pressure levels
8. Precision leak valve is slowly adjusted until chamber Px reaches 10-15mTorr
9. HV enabled and ramped up until the plasma ignites (10-15kV)
10. Adjust leak valve and V/I as needed to stabilize plasma
11. Use NIM BIN to perform timing and counting operations

The following two links are to videos of uploaded publicly on Facebook showing proof of neutron production.

https://www.facebook.com/video.php?v=10 ... =2&theater

https://www.facebook.com/video.php?v=10 ... =2&theater

Hopefully I have presented coherent and substantial enough data to demonstrate neutron emission/detection. Please feel free to accept/challenge my data or ask questions regarding any aspect of my engineering or experimental method.
Attachments
Fusion Run Data 09JAN15.xlsx
(13.45 KiB) Downloaded 126 times
Pulse Height_20mins no Moderator.png
PRA sampling of bare He3 tube without Fusor on
Pulse Height_8mins Fusion.png
PRA sampling during Fusion run
IMG_2671.JPG
Voltage and Current measurements shown on Glassman supply
IMG_2695.JPG
Deuterium plasma @22.5kV 0.3mA
IMG_2632.JPG
Side view of the Fusor equipment rack
Nick Peskosky
NPeskosky@gmail.com

"The whole of science is nothing more than the refinement of everyday thinking." - Albert Einstein

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Richard Hull
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Re: First Neutrons from San Diego

Post by Richard Hull » Sun Jan 11, 2015 7:39 am

Nice report with good discussion of method and gear, but the video tells the real story with the classic removal of the 3He tube from the moderator, killing the count. Nice work! no need at all for further interrogation. I have just added you to the neutron club and welcome to this group of merry fusioneers. Good work on your first successful run, doing fusion in your lab.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
Retired now...Doing only what I want and not what I should...every day is a saturday.

Bruce Meagher
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Re: First Neutrons from San Diego

Post by Bruce Meagher » Sun Jan 11, 2015 8:47 am

Nick,

Congratulations on the outstanding work!

What are you trying to show with the two pulse height spectrum pictures, and why didn’t you capture over the same energy range? The typical He3 neutron capture spectrum doesn’t jump out in your second image, but there are measurable counts at higher energies. Maybe in a future run you could captured both the entire spectrum as well as the discriminated output from your single channel analyzer to emphasize the point. Increasing the run time might even make that 764 keV peak really show itself.

Bruce

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Adam Szendrey
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Re: First Neutrons from San Diego

Post by Adam Szendrey » Sun Jan 11, 2015 10:14 am

Congrats Nick! Wonderful work!

Jack Puntawong
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Re: First Neutrons from San Diego

Post by Jack Puntawong » Sun Jan 11, 2015 11:03 am

Nick,

Congrats on this achievement. You totally deserve it for pushing through to the end. =)

Jack Puntawong

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Jim Kovalchick
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Re: First Neutrons from San Diego

Post by Jim Kovalchick » Sun Jan 11, 2015 11:26 am

Fantastic!

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Nick Peskosky
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Real name: Nicholas Peskosky
Location: San Diego, CA

Re: First Neutrons from San Diego

Post by Nick Peskosky » Mon Jan 12, 2015 12:53 am

Bruce,

I was attempting to show the higher energy pulses registered from neutron capture by the proportional detector but the high amount of gamma/EMI noise in the lower energy ranges tends to skew the histogram display. I'm trying to develop a better coax-->3.5mm adapter to cut down on the noise. When I get a chance I'll perform a longer duration run and see if the typical 764 KeV peak is more defined.
Nick Peskosky
NPeskosky@gmail.com

"The whole of science is nothing more than the refinement of everyday thinking." - Albert Einstein

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Andrew Robinson
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Re: First Neutrons from San Diego

Post by Andrew Robinson » Mon Jan 12, 2015 3:27 pm

Congrats Nick!
I can wire anything directly into anything! I'm the professor!

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Rich Feldman
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Re: First Neutrons from San Diego

Post by Rich Feldman » Mon Jan 12, 2015 7:59 pm

Strong work there.
First time I've seen a wet-chemistry tray in the same frame as vacuum apparatus and HV control panel.
Mike echo oscar whisky! I repeat! Mike echo oscar whisky, how do you copy? Over.

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