Gamma rays over very large areas

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Discussion Overview

The discussion revolves around the generation of large area gamma rays using different systems, specifically comparing the HERMES III facility at Sandia National Labs with Ti Sapphire laser systems. Participants explore the feasibility, efficiency, and potential applications of these gamma ray generation methods, including their implications for simulating nuclear explosion effects.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • Some participants note that HERMES III can generate large area gamma rays through bremsstrahlung radiation, while questioning if Ti Sapphire laser systems can achieve similar results.
  • There is a discussion about the power and efficiency of Petawatt lasers, with some arguing that their short pulses and low total energy make them less effective for gamma ray generation.
  • One participant expresses curiosity about the potential to simulate nuclear explosion effects on military tanks using laser systems, suggesting that larger systems might be necessary for generating extensive gamma ray fields.
  • Some participants challenge the motivation behind generating large area gamma rays, questioning the practical applications and research benefits of such efforts.
  • There are suggestions that increasing the distance from the source or using scattering could help spread out the radiation, though this would reduce intensity.
  • Several participants express disagreement regarding the conclusion that Ti Sapphire laser systems can generate large area gamma rays like HERMES III, with some explicitly stating "No" in response to this claim.

Areas of Agreement / Disagreement

Participants do not reach a consensus on whether Ti Sapphire laser systems can generate large area gamma rays comparable to HERMES III. There are competing views on the efficiency and practicality of using laser systems for this purpose, and the discussion remains unresolved.

Contextual Notes

Participants express uncertainty about the efficiency of converting laser pulses to gamma rays and the implications of using different systems for generating gamma rays over large areas. There are also limitations in understanding the specific energy and dosage relationships involved in these processes.

Who May Find This Useful

This discussion may be of interest to researchers and practitioners in fields related to radiation physics, laser technology, and military applications, particularly those exploring advanced gamma ray generation methods.

Rev. Cheeseman
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TL;DR
Generating gamma rays over very large areas by other means other than large accelerators in order to simulate nuclear explosion effects on military tanks, satellites, missiles, etc.
According to this link https://apps.dtic.mil/dtic/tr/fulltext/u2/a351472.pdf, HERMES III at Sandia National Labs can generate very large area gamma rays by converting the electron beam into bremsstrahlung radiations after hitting the tantalum target. As we can see in the isodose contours in the linked article especially at page 40, the gamma ray field is indeed huge. It makes sense since the target size ranges from the size of transistors to the size of military tanks.

Here, in this link https://spie.org/news/3737-gamma-ray-generation-using-a-laser-accelerated-electron-beam?SSO=1 it was said that Ti Sapphire laser systems have very high power which is at Terawatt and Petawatt level. Ti Sapphire laser systems can be used to generate gamma rays too of course with the aids of some other components, but I'm not sure if the gamma rays generated are the same size as the gamma rays produced by HERMES III.

So, my question is can we generate very large area gamma rays with Ti Sapphire laser systems just like the HERMES III? Maybe by increase the size?
 
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You understand that dosage is basically Energy deposited and you are quoting power for the laser...apples vs apples /s...what is the question ??
 
Petawatt lasers have extremely short pulses, their total energy is small, and converting their pulses to gamma rays isn't particularly efficient.

What is the purpose of having gamma rays over a large area? Scanning over representative places is so much easier.
 
hutchphd said:
You understand that dosage is basically Energy deposited and you are quoting power for the laser...apples vs apples /s...what is the question ??

Sorry for that as I still don't fully understand how accelerators and laser plasma work. HERMES III is 16 terawatt while the titanium sapphire laser system is 30 terawatt which leads me thinking that more powerful gamma rays can be generated through the laser system. But I could be wrong.

I'm curious if we can generate very large area gamma rays that can simulate nuclear explosion effects on military tanks, like the HERMES III, but by using laser systems instead of vacuum diodes, large accelerators, etc. If we can generate the same gamma ray fields over very large areas for example areas with 100+ feet radius with laser systems including the compact and smaller one, it will be like the transition from vacuum tubes to solid-state devices.
 
mfb said:
Petawatt lasers have extremely short pulses, their total energy is small, and converting their pulses to gamma rays isn't particularly efficient.

What is the purpose of having gamma rays over a large area? Scanning over representative places is so much easier.
So, in order to simulate nuclear weapon effects on military tanks which to generate very large area gamma ray fields, the laser system must be big too?
 
I am puzzled by the motivation for the question. Exact numbers for gamma ray exposure to occupants of a tank seem pretty far down humanity's list of things we need to know.
 
hutchphd said:
I am puzzled by the motivation for the question. Exact numbers for gamma ray exposure to occupants of a tank seem pretty far down humanity's list of things we need to know.

It is just a thought experiment, like the analogy of transition from vacuum tubes to solid-state devices. Maybe I should rephrase my question.

The HERMES III generated 22MeV bremsstrahlung gamma ray fields over very large areas while the titanium sapphire laser system can generated 30MeV bremsstrahlung gamma rays according to the second link in my first question. But we're not sure if the gamma rays generated by the laser system can cover huge areas like the HERMES III.

So, in order to generate huge gamma ray fields over huge areas, the laser system must be large too?
 
You can always increase the area by going farther away from the source to make the radiation spread out. Add some scattering if you are impatient (don't want a large tunnel to the target). This makes the intensity go down, of course.
I still don't see the point. Which specific research question would profit from it?
 
mfb said:
You can always increase the area by going farther away from the source to make the radiation spread out. Add some scattering if you are impatient (don't want a large tunnel to the target). This makes the intensity go down, of course.
I still don't see the point. Which specific research question would profit from it?

Ok, so in conclusion, we can use the titanum sapphire laser system to generate intense gamma ray fields over very large areas just like HERMES III. That means scientists can reduce cost and take up less space as HERMES III is much larger than the laser system.
 
  • #10
No
 
  • #11
hutchphd said:
No

Can you give explanations?
 
  • #12
wonderingchicken said:
Ok, so in conclusion, we can use the titanum sapphire laser system to generate intense gamma ray fields over very large areas just like HERMES III. That means scientists can reduce cost and take up less space as HERMES III is much larger than the laser system.
I have no idea how you got that impression from my posts.
 
  • #13
mfb said:
I have no idea how you got that impression from my posts.

Sorry for that. Can you give more detailed explanations and conclusion that can be made from your previous post?
 

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