Can focus be improved using a Fresnel zone plate? https://www.mdpi.com/1996-1944/5/10/1752

I emailed  Dr. Tony Coulson a link to your idea. I hope he can help. I also hope that you let me help you with your project

I think this would work out as long as you get someone to mentor you/ help you with your idea. I would love to get you in touch with someone I know who could help. I am going to get the person's email and send the person a link to your idea.

Hey,

nice idea, but this won't work:

First, the tube you selected has a focal spot size of 3mm. This means that with a tube-object-sensor ratio of 1:1 you can only create images with a feature size of 3mm. Everything smaller will be blurry.

Second, your tube relies on spontaneous field electron emission, which only occurs at the rated operation voltage. That is 150kV, so you get 150keV xray out of it. 150keV penetrates basically anything organic without significant absorption, so you'll be only able to x-ray stuff like Iron and higher atomic numbers.

Also please note that this tube is probably designed to be fully suspended in oil during operation.

Also, fluorescent screens combined with a optical camera make horrible x-ray sensors (from my own experience), especially for x-ray microscopy. Most medical screens have very thick phosphor layers that are great to reduce the dose for the patient as is makes the screen more sensitive, unfortunately this also reduces resolution to ~0.1mm.

I would recommend you getting an used digital x-ray sensor from ebay. For the source, have a look for "microfocus x-ray". I'm afraid at the current point even with a lot of diy enthusiasm it is not possible to achieve what you want for under $1000.

Hi man thanks for interest :) Here is a really pessimistic point of view hahah. Yeah but that's what we are making on here on hackaday.io : facing problem, work hard on what make us dream and maybe achieving it :) !

Honestly I don't know a lot about focusing, spot size ect .... but for my project (the dimension of PROTOTYPE 1.0 are not shown), for what I want to build, this is not a problem. From what I could read,  caracteristics of my x-ray tube are okay for this usage. 

Yeah the big default of my x-ray tube is that changing the energy of the x ray is not easy, the tube is more stable at 150 KeV, but you can run it on lower or even higher energy, but this reduce the life time of the tube. 

Even so, phosphore, calcium ... wich are present in living thing will also make contrast in the sample. I also envisage to make some invasives scan with the use of constrast products like iodine or krypton (on plant for example). Even so, a low constrast image could be used to produce an 3D model. 

Yeah the tube have to be placed under insulating oil. I don't represent it on the PROTOTYPE 1.0 to make it easier to understand how this machine work.

Yes a digital sensor is the best solution, but obviously this is really expensive (even used), that's why I use this solution. I hope to achieve a good resolution with this system. I read a paper wich describe these kind of system (a fluoroscope) and it sayed that it's possible to achieve good resolution who "rivals" with medical imaging. 

I'm really happy with your feedback and your advises, thank you. I know this project is really complex. But I really want to construct it, and that's what I will do, we will see where it takes me hahaha.

Don't hesitate to send me a private message if you want to talk about it more deeply, or give me more advises. Have a nice day man. Maybe you should follow my project to see how I will resolve these problems :)