New Rhodium counter system and moderator for fusor V

This area is for discussions involving any fusion related radiation metrology issues. Neutrons are the key signature of fusion, but other radiations are of interest to the amateur fusioneer as well.
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Dennis P Brown
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Re: New Rhodium counter system and moderator for fusor V

Post by Dennis P Brown »

Yes, the electron can't be confined in a nucleus or at least under normal conditions. The weak force converts one type of quark into another, and the excessive energy shakes the fabric of space and time so an electron (with a lot of K.E.) is created as well as a neutrino. The reverse process can occur but only within collapsing star cores when neutron stars are created and where their electrons and protons are converted into neutrons. A neutron star is just a huge pile of neutrons (maybe a sea of electrons here and there as well as ...maybe ... a sea of quarks in the center.) Nature is strange and wonderous and that we can peak a glimpse into these secrets is just incredible.
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Richard Hull
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Re: New Rhodium counter system and moderator for fusor V

Post by Richard Hull »

Trying to help Finn understand some of the intricacies of activation has led the thread into theoretical nuclear discussions.

The neutron like all quantum ruled particles has a sphere of influence or existence. Up close and personal, the neutron is not neutral, but presents lobed charge regions that move about with both localized positive and negative charges presenting constantly. Back off far enough and it appears neutral.

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
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Finn Hammer
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Re: New Rhodium counter system and moderator for fusor V

Post by Finn Hammer »

Richard, all,

Let's end it here, and my apologies for hijacking the thread.
Back to Rhodium activation!

Cheers, Finn Hammer
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Dennis P Brown
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Re: New Rhodium counter system and moderator for fusor V

Post by Dennis P Brown »

Finn, if anyone hi-jacked this thread it was me but I do feel that being a site that does try to bring useful information to people here, discussions about the underlying physics is part of the forum's function. I should add, thanks' to Richard's thread here, that I have finally (about time, one would think) realized why I failed at activation even though I had far more neutrons then needed. So after following this thread I am determined to correct that mistake and see what occurs.

In any case, back to regular scheduled programming ... ;)
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Richard Hull
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Re: New Rhodium counter system and moderator for fusor V

Post by Richard Hull »

Finn is a hard worker and a doer. I appreciate that. He wants to learn. I really like that. I will bend over backwards and interrupt my own thread to see to it he is pointed in the right direction. Activation and interpreting the tables and charts are all part of the continuing fusion effort that I talk about all the time. Making a fusor and doing fusion should be a starting point in the nuclear physics effort. Improving the fusor, understanding it better, using the fusion as a study in activation are all follow-on goals that should interest any person spending the long-buck with the verve to do and learn more.

Anytime Finn, anytime... Interruptions that forward learning are to be sought out, and welcomed.

By the way, EC (electron capture), makes a neutron in the nucleus and sends the new isotope "down chart" as a proton disappears. Down one atomic number. But....Remember, a neutron is not a proton and an electron. An orbital electron is swiped from the shell and sucked into the nucleus, (captured). Remember, there are no electrons in the nucleus. This EC process is done when a nucleus is unstable due to too few neutrons or is overloaded with protons. Take your pick on which rules the roost here as to the real cause. ( think the neutron is the king here...too few)

Does this tell us, (dare we say it), the neutrons are the source of glue that hold the atom together? No...No....No!!!!! It is the strong force, #!@^**%!&. If the strong force is so strong as to overpower the proton-proton repulsion in the nucleus why do we need the neutrons? "Sit down and shut up and listen up to what I say, you poor dumb student!" Students who ask questions are always to be desired. They change science and expand 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
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Finn Hammer
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Re: New Rhodium counter system and moderator for fusor V

Post by Finn Hammer »

As a reference to the mechanism of neutron capture in Rhodium, Jim posted a nice graphic, depicting the most relevant stages of the incident.
Jim, would you mind sharing which publication this chart originates from.
It would seem most usefull to be able to view that particular level of detail for other elements too.

Cheers, Finn Hammer
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Jim Kovalchick
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Re: New Rhodium counter system and moderator for fusor V

Post by Jim Kovalchick »

Finn, my source of the rhodium decay scheme was from a document that is mostly beyond relevance to our activation interests as it related to use of rhodium's use as an emitter in a self-powered detector.

All the information in the scheme is available in Table of Isotopes. I don't own a copy, but I have the IAEA app on my phone. I highly recommend it.

Jim K
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Richard Hull
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Re: New Rhodium counter system and moderator for fusor V

Post by Richard Hull »

Sadly, as I noted the table of the isotopes has this listed in two separated step diagrams in the back of the book. Only an expert might follow the decay scheme in the back of the T.O.N. A careful following of the front section daughters and product listings will make it clearer. However the one Jim presented gave a good diagram of the cat chasing it own tail, circumnavigation through Rh104.

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
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Richard Hull
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Re: New Rhodium counter system and moderator for fusor V

Post by Richard Hull »

At Finn's suggestion I hereby attach a more readable activation graph in CPM and seconds for those struggling with the 5 second sample rate graphs of the past. I will endeavor to, in future, supply this type of graph.
The graph is from the best run of HEAS 2021. Folks were there watching this happen!

edit: old graph had wrong x axis values. Here is the proper graph 11/5/21

Richard Hull
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RhodiumActivation10-2-21MOD.jpg
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
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Richard Hull
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Re: New Rhodium counter system and moderator for fusor V

Post by Richard Hull »

I post this as a duplicate post from one of Finns postings to explain in some detail the reason for the long continued counting of rhodium well past its 5 X 44 sec half life of ~220 seconds, provides the TIER is high and exposure time is over 5 minutes...

I have never loved rhodium for its fast decay but solely for its fast activation at lower neutron outputs. With Rhodium, a terrible fusor will activate with zero need for any statistical analysis. It is up and hot fast. A fast decay mean a fast activation and the high cross section means a lot of activation per unit TIER.

In these rolling discussions in my recent runs of fusor V, we discussed that activated rhodium actually generates more Rhodium 104 via activated Rh104m and will not die dead even at 600 seconds if you have the snort to blast it hot and long enough. Even I saw that at only 500k n/s TIER with 6 minute activations...It was discussed with Jim Kovalchick coming to the rescue on why this is so with his diagram that followed the long, yet unsuspected chain of rolling activations. Like a giant nuclear echo! But, like all echos they can't live forever.

Refer to Jim's very handy diagram at

viewtopic.php?f=13&t=14084&start=20

It can be seen that if you expose Rh103 for a long time 10 minutes or more, you will generate enough to 104m to keep a statistically detailed, low background adroit GM counting of betas for as long as 20 minutes! following the irradiation of Rh103 is stopped due to Rh104m generating more Rh104 with its 44 sec half life. This is the Beta echo. Totally unexpected, but real and keeps even a 500k n/s TIER exposure counting above background past 600 seconds. More n/s TIER and longer exposure times will show far more prominent above background counting stringing out much longer.

I attach a modified diagram of the echo effect. Even the weak gammas will be counted from Rh104m

Richard Hull
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Rhodium decay level diagram.anno.jpg
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
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Richard Hull
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Re: New Rhodium counter system and moderator for fusor V

Post by Richard Hull »

Well, it is cold here and the current lab temp is 30 degrees. Here is the first and last Rhodium activation of 2022, until more temperate lab conditions exist, probably in the early spring.

The fusor worked much better in the cold than over the last week of operation. over 97,000 CPM at peek operation on 3He system.. 8 - 9 mrem/hr on Remball, 8.1 - 9.3 mrem/hr on PNC-1. 589,000 n/s TIER
The run:
41kv, 10.5 ma, 10.7microns on fusor V. 12 X 129= 1548 cpm on the puny 6 sqcm, 2pi emisson of Rhodium against a 4.1X12 = 49.2 cpm back ground. Result, ~32X background...solid activation on a tiny scrap of Rhodium. I have activated my 6 sqcm of rhodium at 56,000 TIER!

Graph of Rhodium activation below.

Richard Hull
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RhodiumActivation 1-3-22 Modsml.jpg
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
Matt_Gibson
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Re: New Rhodium counter system and moderator for fusor V

Post by Matt_Gibson »

This run is very close to what my setup runs…Looks like I shouldn’t have much trouble with activation once I get my Hdpe here. I was afraid that I was going to need higher voltages (my psu can provide -40kV @ 15mA)

-Matt
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Richard Hull
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Re: New Rhodium counter system and moderator for fusor V

Post by Richard Hull »

30kv in a good system, well run, will give unequivocal activation of silver. I hope to being inducting you into the Elite fusioneers soon.

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
Matt_Gibson
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Re: New Rhodium counter system and moderator for fusor V

Post by Matt_Gibson »

Richard, you can count on it ;-) As soon as my Hdpe arrives, I’ll be back.
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