I What is the point of a spacer in neutron activation?

[says]

I'm just reading over some experimental notes for neutron activation analysis and I see the mention of a spacer being placed between the irradiated sample and the detector face. What does a spacer actually do? I did a quick google but couldn't really find anything.

 

[.Scott]

I'm just reading over some experimental notes for neutron activation analysis and I see the mention of a spacer being placed between the irradiated sample and the detector face. What does a spacer actually do? I did a quick google but couldn't really find anything.

I can think of three potential purposes for a spacer. The first is to fix the distance between the specimen and the detector - to make readings comparable from one to the next. The second is to protect the detector from becoming contaminated by the specimen. The third applies to reactor environments. Spacers are used there to displace whatever fluids (usually water or water solutions) are in the reactor.

Spacers can also have mechanical purposes - as carriers or guides.