I The Graser: Examining a Cold War Spy Story

[sophiecentaur]

I came across a reputedly true bit of Cold War spy stuff in a book "Farewell: the greatest spy story of the twentieth century" by Sergei Kostin.

It's about a KGB defector, Colonel Vladmir Vetrov who blew the structure of the KGB to the French. As a result, the US sowed the seeds of a spoof about US development of a Gamma Ray Laser to the Russians. He's mentioned in Wikipedia so it's not just fiction.

The Russians have always had their fair share of clever Physicists but no one seemed to question this as a possible piece of military technology. It cost them a lot of money and effort to try to do what they thought the US had done.

What could be the basis which made them think that Nuclear transitions could be used in a laser type reaction? Even to think that X ray energy photons could be produced from electron transitions seems crazy.

Is there something that I am missing or was I right to smell a rat about the Graser?

 

[trurle]

I came across a reputedly true bit of Cold War spy stuff in a book "Farewell: the greatest spy story of the twentieth century" by Sergei Kostin.

It's about a KGB defector, Colonel Vladmir Vetrov who blew the structure of the KGB to the French. As a result, the US sowed the seeds of a spoof about US development of a Gamma Ray Laser to the Russians. He's mentioned in Wikipedia so it's not just fiction.

The Russians have always had their fair share of clever Physicists but no one seemed to question this as a possible piece of military technology. It cost them a lot of money and effort to try to do what they thought the US had done.

What could be the basis which made them think that Nuclear transitions could be used in a laser type reaction? Even to think that X ray energy photons could be produced from electron transitions seems crazy.

Is there something that I am missing or was I right to smell a rat about the Graser?

The hypothetical "nuclear-pumped laser" relying on electron transition can in principle produce hard X-rays (30 kEv for xenon, or 60 kEV for tungsten rod lasing medium) which is quite close to lower edge of gamma-rays (100 kEv) to be sometimes named gamma-laser.

Also, some work was done to see if gamma-lasing can be achieved with naturally occurring meta-stable nuclear isomer of tantalum. The stimulated gamma-ray amplification was actually achieved in the US (by about 3%), but without gamma-ray mirrors (which do not exist) true gamma laser is not possible to construct for now.

 

[sophiecentaur]

gamma-ray mirrors (which do not exist)

I found out about using grazing incidence reflection on paraboloid mirrors for X ray telescopes but I imagine the higher the energy, the more shallow the angle needs to be. Hard to make an etalon on that basis.

 

[Roberto Teso]

I think you can find very interesting to read this: https://stfc.ukri.org/news/gamma-ray-laser/ and deepen by reading their paper Coherent gamma photon generation in a Bose–Einstein condensate of ^135m Cs downloadable on ScienceDirect.

 

[trurle]

I think you can find very interesting to read this: https://stfc.ukri.org/news/gamma-ray-laser/ and deepen by reading their paper Coherent gamma photon generation in a Bose–Einstein condensate of ^135m Cs downloadable on ScienceDirect.

That was a speculative calculation only, not based on any experiment. With their Bose-Einstein condensate assumption authors do ignore non-unity Debye-Waller Factor in real systems. DBF below 1 can easily result in more absorption than amplification.

 

[Roberto Teso]

May be, but in the article they written:

This research is no longer just theory. UCL’s Professor of Physics, Professor Ferruccio Renzoni, and his team are now busy setting up an experiment at the University of Jyväskylä Accelerator Laboratory in Finland. Key components, assembled at UCL, are already in place in Finland at the experimental facility. There, a cyclotron particle accelerator will produce the unstable caesium, and the UCL’s laser system will trap and cool it to 100 nano-kelvin, with a view to successfully producing the world’s first coherent gamma-ray emissions.

so, they are building a real experiment, not only calculations.

 

[trurle]

May be, but in the article they written: so, they are building a real experiment, not only calculations.

Yes, recently (in last 20 years or so) do exist an awful practice of "multiplying" papers - first describing simulation results, and in next paper the intermediate results, next paper engineering of research equipment etc up to experimental results, regardless of positive or negative results. Because positive results are typically in 1-10% range depending on area of research, the practice produce a lot of published garbage similar to one we are discussing.
Lets wait for five years and see if the UCL team will be able to produce anything better than speculations.

 

[sophiecentaur]

Thanks for the input chaps. So far, it seems that the Graser is still far from a potential Weapon, which is what the Russians (and the West) would have liked. That episode was a great example of the war of misinformation that was being waged flat out.
We now have 5G in its place.

 

[Klystron]

I came across a reputedly true bit of Cold War spy stuff in a book "Farewell: the greatest spy story of the twentieth century" by Sergei Kostin.

It's about a KGB defector, Colonel Vladmir Vetrov who blew the structure of the KGB to the French. As a result, the US sowed the seeds of a spoof about US development of a Gamma Ray Laser to the Russians. He's mentioned in Wikipedia so it's not just fiction.

The Russians have always had their fair share of clever Physicists but no one seemed to question this as a possible piece of military technology. It cost them a lot of money and effort to try to do what they thought the US had done.

What could be the basis which made them think that Nuclear transitions could be used in a laser type reaction? Even to think that X ray energy photons could be produced from electron transitions seems crazy.

Is there something that I am missing or was I right to smell a rat about the Graser?

Thanks for this addition to my planned summer reading. My local library does not list the Kostin book but does have DVD copies of a French/Russian movie that matches your description. Hope the movie shows diagrams of the hypothetical graser and what applications were expected.

The Soviets developed gyrotrons during this period, originally as oscillators but then as amplifiers in the sub-millimeter wavelengths between masers and lasers. While not directly related to gamma emissions, an analogy to magnetron and klystron use should be interesting considering that gyrotrons are not constrained by cavity wavelength size thus avoiding overheating at higher frequencies and power.

The "gamma mirror" problems mentioned in some replies are also avoided using a gyrotron analogy. I suppose the intended applications of the graser device would help determine how useful the gyro-analogy proves. Studying the advances in this technology -- free-electron lasers, terahertz radiation, xasers, and grasers -- post Cold War, should provide an interesting summer.

 

[sophiecentaur]

Thanks for this addition to my planned summer reading.

Hmm. It wasn't amongst my best reads of recent years. The style is flat and it goes on and on about details of Soviet life that are really not that interesting. The central character is strange and not a sympathetic one, despite his contribution to the West's fortunes. I wouldn't necessarily suggest Dan Brown instead; he's ghastly in a different way. If you want a nice long read which keeps you at it, try Wolf Hall by Hilary Mantel. You will learn some interesting (albeit a bit biassed) English history at the same time.

 

[mfb]

Even to think that X ray energy photons could be produced from electron transitions seems crazy.

Huh? That is done routinely. Every x-ray machine does it.
If you mean gamma rays: By definition radiation from high energy electronic transitions are called x-rays, not gamma rays, but that is purely a convention for the names.

A crude x-ray laser pumped by a nuclear explosion was an actual project in the US: Project Excalibur. No mirrors, obviously, it is a single-pass amplification.

I don't see gamma ray lasers discussed as serious project.

 

[sophiecentaur]

Huh? That is done routinely. Every x-ray machine does it.

Yeah, I know about Xray emissions. I was referring to the possibility of getting a population inversion so that tasing could occur. Are there examples of metastable states existing in those shells? I was thinking that the outer electrons would have too much of an effect to get well defined energy levels.

 

[mfb]

See the Wikipedia article I linked. Accumulation of electrons in the outer shells is quicker than filling the inner shells, you can get population inversion if the timing is right.

 

[sophiecentaur]

See the Wikipedia article I linked. Accumulation of electrons in the outer shells is quicker than filling the inner shells, you can get population inversion if the timing is right.

Ah - that bit was buried in amongst more chatty stuff. From what it says about X Ray Lasers, we are talking about 1W per atom. That's some power! I guess the Russians would not have been too worried if they had had the details.

 

[jim hardy]

oh my goodness

Hafnium and the curse of imagination

https://www.aps.org/publications/apsnews/200706/backpage.cfm
old jim