Neutron Club Application- Zan Chaudhry
- Richard Hull
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- Real name: Richard Hull
Re: Neutron Club Application- Zan Chaudhry
Many fusion folks, over time, learn how to tell their instruments are lying or have gone astray. Much like Kuba points out, looking at the glow and looking at the applied voltage and current can really tell an advanced or advaning user that his or her vacuum reading is crap and force them to check their vacuum gauge for calibration or failure. The true newbie is at the mercy of poor instrumentation in many instances and will have to go to the school of hard-knocks before picking a lot of this up. One cannot over-emphasize the need for at least a TC gauge in the foreline. (Sadly, even this gauge can be off a bit at the extreme low end, but is is better than a poke in the eye with a sharp stick and 50,000% better than a junky refrigeration gauge.)
Richard Hull
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
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
- Zan_Chaudhry
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- Joined: Tue May 17, 2016 9:19 pm
- Real name: Zan Chaudhry
- Location: Ellicott City, MD, USA
Re: Neutron Club Application- Zan Chaudhry
I think I've got it all now:
1. 12 minute operation
2. 35kV average voltage
3. 24mA average current
4. 5-15 micron pressure (on my gauge)
5. I attached pictures of grid. Most of the time it was in the golden state.
6. I attached dosimeter images. (the bubbles are only in the top because my dosimeter slipped sideways during the test, aiming the top into the chamber at an angle, but it was under my lead shielding so I didn't notice.)
7. Dosimeter sensitivity: 73 bubbles per mrem
8. 6 inch dosimeter distance from neutron source
9. The bubbles cannot be counted because they formed a foam.
10. My x ray counts averaged around 40k cpm, with some moments over 70.
11. I added some pictures of the test setup.
1. 12 minute operation
2. 35kV average voltage
3. 24mA average current
4. 5-15 micron pressure (on my gauge)
5. I attached pictures of grid. Most of the time it was in the golden state.
6. I attached dosimeter images. (the bubbles are only in the top because my dosimeter slipped sideways during the test, aiming the top into the chamber at an angle, but it was under my lead shielding so I didn't notice.)
7. Dosimeter sensitivity: 73 bubbles per mrem
8. 6 inch dosimeter distance from neutron source
9. The bubbles cannot be counted because they formed a foam.
10. My x ray counts averaged around 40k cpm, with some moments over 70.
11. I added some pictures of the test setup.
- Scott Moroch
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Re: Neutron Club Application- Zan Chaudhry
Zan,
I like the way you presented your data however, I am slightly concerned about your BTI measurements. I am not an expert on Bubble dosimeters but those bubbles near the top do not appear as uniform and concise as they usually are/should be. Perhaps the quality of the image low. Did the BTI ever make contact with the chamber itself? During operation the chamber's temperature can rise significantly. The bti is sensitive to high temperature and can result in false bubbles. I have attached an image below of Bubbles I saw when I ran my fusor.
Also, regardless of the angle of the BTI, you would anticipate a relatively uniform distribution of bubbles in the BTI (generally speaking as the neutrons are emitted isotropically from the fusor.
Best of luck to you.
Scott Moroch
I like the way you presented your data however, I am slightly concerned about your BTI measurements. I am not an expert on Bubble dosimeters but those bubbles near the top do not appear as uniform and concise as they usually are/should be. Perhaps the quality of the image low. Did the BTI ever make contact with the chamber itself? During operation the chamber's temperature can rise significantly. The bti is sensitive to high temperature and can result in false bubbles. I have attached an image below of Bubbles I saw when I ran my fusor.
Also, regardless of the angle of the BTI, you would anticipate a relatively uniform distribution of bubbles in the BTI (generally speaking as the neutrons are emitted isotropically from the fusor.
Best of luck to you.
Scott Moroch
"In the middle of difficulty lies opportunity"
-Albert Einstein
-Albert Einstein
- Richard Hull
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Re: Neutron Club Application- Zan Chaudhry
Scott is correct. Rerun. We need to see formal bubble production that are clean and clear. 70 or more bubble per mrem is a very sensitive BTI! Those images do not resemble real fusion, either. Those in the know here, know. Sorry to be such a stickler, but proof is proof and we need it.
I attach images of my setup when I used the BTI and a black and white image of real-time fusion from my video camera on the monitor screen.
Note** the BTI is very sensitive to heat! Mount it where vertical convection heat from the fusor cannot warm it!
Richard Hull
I attach images of my setup when I used the BTI and a black and white image of real-time fusion from my video camera on the monitor screen.
Note** the BTI is very sensitive to heat! Mount it where vertical convection heat from the fusor cannot warm it!
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
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
- Zan_Chaudhry
- Posts: 23
- Joined: Tue May 17, 2016 9:19 pm
- Real name: Zan Chaudhry
- Location: Ellicott City, MD, USA
Re: Neutron Club Application- Zan Chaudhry
Okay, I've got a rerun.
1. 10 minute operation.
2. 24-35kV voltage. (lots of variance, mainly in the mid 20kV's)
3. 40 to 60 mA (I actually blew my variac's fuse at the end).
4. 10 micron pressure
5. Grid picture attached.
6. Dosimeter pictures attached.
7. 73 b/mrem sensitivity
8. 8 inch dosimeter distance from ideal neutron source.
9. 7 bubbles
10. Really high x ray counts, in the couple hundred k cpm. I attached an image actually.
1. 10 minute operation.
2. 24-35kV voltage. (lots of variance, mainly in the mid 20kV's)
3. 40 to 60 mA (I actually blew my variac's fuse at the end).
4. 10 micron pressure
5. Grid picture attached.
6. Dosimeter pictures attached.
7. 73 b/mrem sensitivity
8. 8 inch dosimeter distance from ideal neutron source.
9. 7 bubbles
10. Really high x ray counts, in the couple hundred k cpm. I attached an image actually.
- Richard Hull
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Re: Neutron Club Application- Zan Chaudhry
Zan, I have added your name to the fusioneers listing. Good going.
Richard Hull
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
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
- Rich Feldman
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Re: Neutron Club Application- Zan Chaudhry
Hooray for Zan!
I think the very last round was critical.
As others have said, your previous-round bubble pictures didn't match the familiar signature of neutron doses.
I bet they show us the signature of detector gel getting too hot in a small region. Fortunately it was reversible, or you had a spare detector. The scientist in me would try to reproduce that effect, by local heating in the absence of a fusor. That would be analogous with Roentgen or Becquerel steering off track to investigate unexpected glows or photo-plate fogging.
I think the very last round was critical.
As others have said, your previous-round bubble pictures didn't match the familiar signature of neutron doses.
I bet they show us the signature of detector gel getting too hot in a small region. Fortunately it was reversible, or you had a spare detector. The scientist in me would try to reproduce that effect, by local heating in the absence of a fusor. That would be analogous with Roentgen or Becquerel steering off track to investigate unexpected glows or photo-plate fogging.
All models are wrong; some models are useful. -- George Box
- Zan_Chaudhry
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- Joined: Tue May 17, 2016 9:19 pm
- Real name: Zan Chaudhry
- Location: Ellicott City, MD, USA
Re: Neutron Club Application- Zan Chaudhry
Thank you everyone for everything. I have been looking forward to this for a long time. But this is nowhere near the end of my fusor endeavors. I'm looking forward to more progress in the future (chamber upgrades, grid upgrades, new gauge, calibrate my 3He tube, and ion guns!). I'm thinking about taking a break now though, and maybe trying to build a Van de Graaf just for fun.
PS: And also, my bubbles have grown, and some smaller ones are now visible, so my new count is 11.
Thanks again,
Zan
PS: And also, my bubbles have grown, and some smaller ones are now visible, so my new count is 11.
Thanks again,
Zan
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Re: Neutron Club Application- Zan Chaudhry
Congratulations on the neutron club Zan! I've been watching this thread from the start, and your setup and persistence is inspiring.
- Dennis P Brown
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Re: Neutron Club Application- Zan Chaudhry
Excellent work - congratulations.
- Zan_Chaudhry
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- Real name: Zan Chaudhry
- Location: Ellicott City, MD, USA
Re: Neutron Club Application- Zan Chaudhry
Thank you!