Dear Recep Kurtulus ,

you know that the x-ray attenuation increases with the atomic number and with the thickness/mass coverage/concentration of these elements of the shield.

So any replacement of Pb (from the x-ray/gamma optical point of view) should be done via a quite high atomic number element or a combination of such elements embedded in an appropiate matrix.

Sr (Z=38) is a candidate for this:

Article Lead free X-ray shielding glass

as well as Bi (Z=83, next to Pb):

https://www.xraycurtains.com/products/transparent-lead-free-acrylic-radiation-protection-window

For example Ba (Z=56) is used in radiation shielding concrete as well as in combination with Pb in radiation shielding glass.

E.g.:

Article Design, structure, microstructure and gamma radiation shield...

Dear Recep Kurtulus,

The goal is to replace Pb on those materials. However, very dense materials would be necessary, polymeric, mineral, that blocks or absorbs the photon energy. In a polymeric solution, the Interaction needs to avoid accelerated aging; Fast aging is the limitation nowadays, a severe central problem.

Best regards,

WNM

Dear Gerhard Martens

Many thanks for your kind sharing. The replacement of Pb or PbO is not so easy, therefore we are agreed on high-density substance incorporations. However, what I'm trying to say that almost all commercial radiation shielding glass materials are based on PbO content, however, the literature studies are striving for non-lead ones. In this sense, what will be next for the commercial ones? I mean, what is the next lead-free candidate for commercialization?

With warm regards.

Dear Wagner Da Nova Mussel

Thanks a lot for your kind interest. We are totally agreed on dense material existences for effective radiation shielding. However, the debate is still apparent about the toxicity of Pb, then is not it worth replacing it with other glass systems and let them commercialize?

With kind regards.

Dear Recep Kurtulus ,

From a commercial point of view, a new solution is only viable if consistent. So, even with up-and-coming dense materials already available, if they demand a relatively short replacement time due to accelerated aging, the solution is not ideal. Pb doped glasses shielding rest for a lifetime; Dense materials will compete if the lifespan achieves similarities in protection and durability.

Best regards

WNM

The idea behind the usage of lead oxide, for radiation shielding could have emerged from the concept, that in all radioactive transformation, the end product is always lead, and naturally we cannot think of toxicity. Radiation is far more toxic than lead. There is a possibility that nano lead may require more findings to arrive a solution.

Dear Govindarajan Maniraju, is radiation really far more dangerous than chemical toxicity (e.g. of lead)? I mean, sure, high doses of any of the two will cause serious problems. But while radioactivity decays over time, chemical activity (or ability to react with some reagent) persists unchanged throughout time. Could you comment more on that?

If the chemical activity could persists unchanged with time, the entire medical field could not have survived in these 200 years, yes, I mean to say that, it can be treated chemically or biochemically..

We have to consider what kind of radiation? Particles or only photons. The absorption profiles and attenuation are there for each case. Without going into science I will say my personal opinion is in composite plastics with layering of different orientations of different high Z, high A, high e. That’s the resonable solution for general radiation no matter the material of choice of doping. For specific applications it’s totally different. Specific doping can increase the electron holes for example and with increasing photons some plastics increase efficiency. But general shielding, I think the future is composite layering and each material for alphas, betas, gammas.

Dear Emmanouil Tzomos

Many thanks for your explanations.

Thank you kindly Recep Kurtulus . Do you agree with my points? is there a place you would like to add or correct?

Dear Emmanouil Tzomos

I agree with you on your ideas. However, we should think of a "transparent appearance" in radiation shielding materials so as to provide an observation window for medical applications. Therefore, for me, the importance of glass in radiation shielding will not be ended but increased day-to-day.

Recep Kurtulus true. Indeed we need transparent materials. I have to add that composite plastics exists and researched with high degree of manipulation to their dispersive qualities. It starts by monocrhmatic study and extends to range. Both transparency can be achieved and many would agree that the pros/cons are there. Yet personally talking do I love glass? Yes. Do I think of it in any case superior and also account for its more expensive yet also feasible composite manufacturing? The challenge that it’s solid-liquid nature gives? Yes. Of its enrichment with oxides or even the old-new idea of noble metal nanoparticles? Yes. But ideally yes. An art superior, expensive and tough on application. A tailored factory suit not democratically factory made. I very much agree with you but on this basis.

I am sorry if I was to lastly add. We have to remember dispersive properties are also dynamical from the degree of non or minimal rigidity to highly shifting or adaptable. A small crude example, transparent-opaque commercial glass walls for offices. Degradation, ionization, excitation, etc all there for us to struggle with and yet take advantage. I find thinking about glass again a really nice thing.