In this space, visitors are invited to post any comments, questions, or skeptical observations about Philo T. Farnsworth's contributions to the field of Nuclear Fusion research.
Subject: More book wormin'
Date: Jan 25, 3:58 pm
Poster: Richard Hull
On Jan 25, 3:58 pm, Richard Hull wrote:
As we are totally snowed in here in the south with 18" of th' white stuff, I poured over and organized more paper work today. I found two more references related to neutron dose rate and "fluence".
The NRC likes the figure 2.9X10e7 n/sec/sq.cm./rem
for 2.45mev Neutrons.
A table from and ICRU report #20, 1971 give a nice ready to use value of:
8.0 neutrons/sec/sq.cm./mrem for 2.45 mev neuts.
These are not far from the reduced values given here recently and I like the 8.0 neutron figure for the mrem and will use it exclusively in the future.
Also some corrections.....
Some of the bonner sphere units and other neutron survey meters deliberately over read the actual dose in an effort to play it safe and not allow accidental overdoses on "their watch" I found one manufacturer that is so frightened of the 1MEV RBE 11 neutron that it gives a correction ratio on a supplied graph of 8:1 for the measured dose versus the theoretical dose based on the rpg curve! I guess they supply that graph for those poor slobs trying to do flux measurements with their survey meters. Some of this is due to the type of thermalization done with a mix of inner borons shielding, cadmium and gadolinium moderator screens, in addition to multiple Polyethylene moderator cylinders.
The thought here is to snag all the manufacturer's data on any rate meter you get or you will probably end up overestimating your neutron production. This is why a proton recoil system is just a better deal albeit requiring a number of skills not often encountered in a single person and equipment found only in some of the more advanced hobbyist's labs.
- Re: More book wormin' (neutrons) - Jim Lux Jan 25, 6:11 pm