Program - Brookhaven National Laboratory

The European Activation SYstem has been re-engineered and re-written in modern programming languages
so as to answer today’s and tomorrow’s needs in terms of activation, transmutation, depletion, decay and
processing of radioactive materials. The new FISPACT-II inventory code development project has allowed
us to embed many more features in terms of energy range: up to GeV; incident particles: alpha, gamma,
proton, deuteron and neutron; and neutron physics: self-shielding effects, temperature dependence and
covariance, so as to cover all anticipated application needs: nuclear fission and fusion, accelerator physics,
isotope production, stockpile and fuel cycle stewardship, materials characterization and life, and storage
cycle management. In parallel, the maturity of modern, truly general purpose libraries encompassing
thousands of target isotopes such as TENDL-2012, the evolution of the ENDF-6 format and the capabilities
of the latest generation of processing codes PREPRO, NJOY and CALENDF have allowed the activation
code to be fed with more robust, complete and appropriate data: cross sections with covariance, probability
tables in the resonance ranges, kerma, dpa, gas and radionuclide production and 23 decay types. All such
data for the five most important incident particles (n, p, d, α, γ) are placed in evaluated data files up
to an incident energy of 200 MeV. The resulting code system, EASY-II(12) is designed as a functional
replacement for the previous European Activation System, EASY-2010. It includes many new features
and enhancements, but also benefits already from the feedback from extensive validation and verification
activities performed with its predecessor. This work was funded by the RCUK Energy Programme under
grant EP/I501045.
PR 49
’List-Mode’ Data Acquisition and Analysis for a Compton Suppression System
R. Britton, P.H. Regan, Centre for Nuclear and Radiation Physics, Department of Physics, University of
Surrey, Guildford, GU2 7XH, UK.
Compton Suppression techniques have been widely used [1] to reduce the Minimum Detectable Activity
(MDA) of various radionuclides when performing gamma spectroscopy of environmental samples. This is
achieved by utilising multiple detectors to reduce the contribution of photons that Compton Scatter out
the detector crystal, only partially depositing their energy. Photons that are Compton Scattered out of
the primary detector are captured by a surrounding detector, and the corresponding events vetoed from
the final dataset using coincidence based fast-timing electronics. The current work presents the use of
a Lynx T M data acquisition module from Canberra UK (Harwell, Oxfordshire) to collect data in ‘List-
Mode’ [2], where each event is time stamped for offline analysis. A post-processor developed to analyse
such datasets [3] allows the optimisation of the coincidence delay, and then identifies and supresses events
within this time window. This is the same process used in conventional systems with fast-timing electronics,
however in the work presented, data can be re-analysed using multiple time and energy windows. All data
is also preserved and recorded (in traditional systems, coincident events are lost as they are vetoed in real
time), and the results are achieved with a greatly simplified experimental setup. Monte-Carlo simulations
of Compton Suppression systems have been completed to support the optimisation work, and are also
presented here. This work is supported by grants from the Engineering and Physical Sciences Research
Council (EPSRC-UK).
[1] Britton R (2011) J Radioanal Nucl Chem 292(1):33-39 [2] Burnett J, Davies A (2011) J Radioanal Nucl
Chem 288(3):699-703 [3] Britton R (2012) J Radioanal Nucl Chem, DOI 10.1007/s10967-012-1811-1
PR 50
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