[d2n-analysis-talk] Radiation lengths for the yellow cover

[Diana Parno]

I've done a few calculations for candidate materials for the yellow  
cover on the target enclosure. I looked over the organic synthetics in  
the PDG table of Atomic and Nuclear Products and Materials, from nylon  
to polyvinyltoluene. A 35-mil thickness of these materials does not  
represent many radiation lengths; the maximum, for Teflon, is 0.0056  
radiation lengths. (The minimum is 0.00177 for polyethylene.) The  
corresponding mean energy loss, at worst, is 0.56% (again, for  
Teflon); the best is 0.18%.

This compares to a 2.2% mean energy loss for the glass wall of the  
target cell, assuming a 45-degree scattering angle. The contribution  
from the glass is between 4 and 12 times larger than that from a 35- 
mil yellow cover.

Interestingly, a 35-mil thickness of any of these plastics would be  
the second-largest contribution to the energy loss of the outgoing  
particles.  I've added the whole set of tables to the new wiki page https://hallaweb.jlab.org/wiki/index.php/Energy_Loss_%28d2n%29 
  , linked to from the main page as "Energy Loss (d2n)".

Best,
Diana