And I also wanted to ask if I constructed a wall made out of it, with GCRs and SEPs and Neutron radiation (basically every radiation in space) from the other side, how many kgs per m^2 of H-BNNT would be required to bring the radiation levels below the maximum permissible limit? For example, if I constructed a wall out of polyethylene, then it would be 7 metric tonnes per m^2, according to http://space.alglobus.net/papers/Easy.pdf. I want to know this value, along with the density, for H-BNNT. Please cite your sources as well, since I need to reference this.

  • Is not a question about the density of H-BNNT more something for those over at chemistry? – Hohmannfan Apr 18 '16 at 15:13
  • I am using it for calculating the wall of a spacecraft, or at least a general question about radiation protection, so I figured it will go here. No problem, i will add it there also. Can you help me out with this? – VSA Apr 18 '16 at 15:18
  • H-BNNT is something you would like to use for neutron shielding, but that is not the most needed type of shielding in space. Charged particles, gamma and x-rays is the problem there. Against those, higher density materials is the thing you go for. That is not the kind of properties you get from elements with a low atomic number, like boron and nitrogen. – Hohmannfan Apr 18 '16 at 15:28
  • I will add layers of polyethylene as well – VSA Apr 18 '16 at 15:35
  • The same question should not be posted on two sites. That would spread information around, making it harder to find, and mean people answering would often waste their time because they don't realize someone else already wrote a good answer. It is known as cross-posting. Did you already post the 2nd question? – kim holder Apr 18 '16 at 15:43
up vote 3 down vote accepted

You might be interested in this paper: Properties of H-BNNT for radiation shielding applications. It briefly mentions how the neutron absorbing properties of the material can be used for radiation shielding in space, but the main purpose is to find a value for the density of it. A simulation approach is used (it is not clear if someone has actually managed to produce the material yet), and the paper concludes with a density of 2.62 g/cm³

A definitive value for how many kg/m² of shielding material is very difficult to give any measure for. Firstly, the amount of radiation received at various locations in space varies extremely, secondly, tolerable radiation doses is dependent on mission length, and the properties for H-BNNT for non-neutron radiation seems hard to find.

Finally, bringing mass just to act as shielding is a last resort in space exploration as every gram counts. A more common approach is to use for example tanks of waters or the fuel tanks for that purpose.

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