Re: Bonner Sphere Unfolding

[JPreisig@AOL.COM]

Hmmmmmm,


      This is from:    jpreisig@aol.com   .



      Dear Gus Potter:


              There are many Bonner Sphere unfolding codes --- some are described

in Patterson and Thomas' book "Accelerator Health Physics".  More recent

descriptions can be found in Cossairt's Accelerator Health Physics

coursebook (Cossairt is at FermiLab) --- "Topics in Radiation at Accelerators:

Radiation Physics For Personnel and Environmental Protection".


              Some unfolding codes can be obtained from RSICC (the Radiation

Shielding Information Center or whatever it is called now --- Oak Ridge, Tenn.).

Codes are usually available from RSICC for a modest handling charge.  Make sure

the unfolding code you are using has response matrices for the detectors you

are actually using.  I have used BON4/BON5 with some success.  It may

be available from Henry Kahnhauser at Brookhaven Lab.  RSICC has a web-site,

I think.


     Other unfolding codes are:  LOUHI, BUNKI, etc.  There are many.  The people

who do Bonner work at Los Alamos might be willing to share their unfolding

code with you --- call 'em up.  Hertel at Georgia Tech does Bonner work.

Also Paul Goldhagen at Environmental Measurements Lab (NY City).  I think

Goldhagen is doing some deconvolution of results, as opposed to unfolding.

Maybe he is solving for something different than what I was looking for.


     The Bonner unfolding problem is mathematically underdetermined.  One

has six to eight detector counting data points, and one is solving for

flux densities (or fluences) in 25 or 32 energy bins.  This is discussed

in Patterson & Thomas, and in a scientific memorandum from the Princeton-

Penn Accelerator (a 1960's or 1970's paper by Awschalom).  Iterative 

unfolding solves the problem, as well as other solution techniques.


      Questions, just e-mail me???   Good Luck!!!!


                         Regards,        J.R. Preisig, Ph.D.