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Title: PENTRAN Modeling for Design and Optimization of the Spherical-Shell Transmission Experiments

Conference ·
OSTI ID:786232

The development of PENTRAN models and new methodologies for accurate and efficient simulations for the design and analysis of time-of-flight (TOF) experiments is discussed. The experimental setup measures the transmission of accelerator-generated neutrons (E > 1 MeV) through spherical iron shells using the TOF spectroscopy. The TOF facility includes a collimator, a thick wall with a hole, a TOF tunnel, and a detector placed {approx}620 cm from the neutron source. The goal of the experiment is to correlate the measured spectrum to different types of interactions, such as the total nonelastic-scattering cross section and its various components. The development of several 3-D PENTRAN models and the effectiveness of new quadrature sets are discussed. Initial calculations by means of the developed 3-D discrete ordinates model of the TOF experimental setup using the PENTRAN code with the S{sub 20} level-symmetric quadrature resulted in inaccurate solutions due to ray effects. To overcome this difficulty, new quadrature sets with local refinement capability were used. These new quadrature sets allowed more accurate, yet efficient, calculations. This study indicated that for the TOF model the P{sub n}-T{sub n} (Chebyshev) set with ordinate-splitting yields accurate results in a relatively short time.

Research Organization:
The Pennsylvania State University, University Park, Pennsylvania (US); National Institute of Standards and Technology, Gaithersburg, Maryland (US); Ohio University, Athens, Ohio (US)
Sponsoring Organization:
US Department of Energy (US)
OSTI ID:
786232
Report Number(s):
ISSN 0003-018X; CODEN TANSAO; ISSN 0003-018X; CODEN TANSAO; TRN: US0108849
Resource Relation:
Conference: 2001 Annual Meeting, Milwaukee, WI (US), 06/17/2001--06/21/2001; Other Information: Transactions of the American Nuclear Society, volume 84; PBD: 17 Jun 2001
Country of Publication:
United States
Language:
English