Looking for information on gamma light sources

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Discussion Overview

The discussion centers on gamma light sources with energies of 10 MeV or higher, exploring their production methods, applications, and specific reactions of interest. Participants share insights on electron accelerators, particularly linear accelerators (LINACs), and their relevance to radiation oncology and nuclear reactions.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant inquires about gamma light sources, specifically their production methods and energy spectra, suggesting that electron accelerators with tungsten or tantalum targets may be involved.
  • Another participant confirms that such gamma rays are produced with electron linacs and provides a reference to a relevant workshop paper.
  • A third participant echoes the previous point about electron linacs and expresses appreciation for the referenced paper.
  • Additional information is provided about commercially available LINACs from manufacturers like Varian and Siemens, noting their use in radiation oncology and the potential concerns regarding fast neutrons from photoneutron reactions.
  • One participant expresses interest in gamma emissions in the range of 5 to 12 MeV, linking them to neutron capture in structural alloys and suggesting implications for chemical physics related to corrosion and radiation-induced segregation.

Areas of Agreement / Disagreement

Participants generally agree on the production of high-energy gamma rays using electron linacs, but there are varying interests and applications discussed, particularly regarding the specific energy ranges and their implications in different contexts.

Contextual Notes

Some discussions involve assumptions about the energy thresholds and the specific reactions being investigated, which may not be universally applicable across all contexts. The references provided may not cover all aspects of the topic.

mesa
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TL;DR
In need of information on high energy and flux gamma light source for nuclear transmutation experiments.
Hello, I am looking for something a bit out of my wheelhouse today, gamma light sources (10 MeV or higher on the max energy threshold).

Does anyone here have experience or more information on these machines? Are they typically electron accelerators utilizing a tungsten or tantalum target? I am guessing we would see a spectrum similar to when measuring high energy Betas during gamma spectroscopy for 'low' energies (considering running a Pb or Bi alloy with a high energy Beta emitter post NAA for tighter measurements next week to get a better look at these spectrums).

I ask because I am interested in running the Ra226+g-->Ra225+n reaction and subsequent beta minus decay to Ac225 for comparrison to our reactor method.

This requires a high energy gamma outside of what can typically be made in a reactor or with our accelerator so need to do some some digging. I see the folks at TUNL using the HIGS have an article stating they can hit 10^10g/s above 25MeV; I am assuming the 'g' is for gamma in their writeup.

Either way, any information is appreciated!
 
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Such gamma rays are produced with electron linacs.

See - International Workshop on Next Generation Gamma-Ray Source (readily accessible).
https://arxiv.org/abs/2012.10843

Good set of references and contacts.
 
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Astronuc said:
Such gamma rays are produced with electron linacs.

See - International Workshop on Next Generation Gamma-Ray Source (readily accessible).
https://arxiv.org/abs/2012.10843

Good set of references and contacts.
I enjoyed the paper so much I printed a copy for my collection, thank you Astronuc.
 
There are some commercially available LINACs that produce electrons and gammas for radiation oncology. Two major manufacturers are Varian and Siemens.

https://www.oncologysystems.com/res...h-energy-linear-accelerators-comparison-chart
https://www.oncologysystems.com/res.../siemens-linear-accelerators-comparison-chart

Fast neutrons from photoneutron (γ,n) reactions induced by high energy gammas (E > 7 MeV) are a concern in medical oncology.

Secondary neutron spectra from modern Varian, Siemens, and Elekta linacs with multileaf collimators​

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2738742/

Monte Carlo characterizations mapping of the (γ,n) and (n,γ) photonuclear reactions in the high energy X-ray radiation therapy​

https://www.sciencedirect.com/science/article/pii/S1507136713010031

I'm interested in gammas in the range of 5 to 12 MeV, which are induced by neutron capture in certain nuclides found in structural alloys, the main culprit being Ni-isotopes. There is circumstantial evidence to suggest the presence of high energy gammas influences the chemistry (chemical physics) of alloys with respect to corrosion and radiation-induced segregation.
 

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