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University of Denver

Presented to Henderson DUSELCollaboration meetings, Nov. 18-19, 2005

Jonathan F. Ormes, Ze’ev Shayer, Anneliese Andrews

JOrmes@du.edu

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DU science facilities in Clear Creek County Mt.Evans summit – 4,300 meters altitude, paved highway, 15 air-miles from HendersonCosmic ray research history: 1930 Compton; 1939 Rossi; 1950s/60s – multi-university research activities.Continuing science: 1972 astronomical facilities, 1997 upgrades

Quark research 1966 New telescopes 1997

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Potential synergies?: Mt. Evans and HUSEP•Joint outreach efforts•Contemporaneous particle measurements

Info and details: www.du.edu/physastronJon Ormes/Bob Stencel 303-871-2135

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DU PlanModel the radiation environment for DUSEL proposals

Design for low background test lab

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Simulation tool for experiment developers

Match to background measurementsEvolves to full 3-d spatial model of the mine and overburden

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Computations

•Experiment simulation tool

•Muons and atmospheric neutrinos•Penetration, energy spectra & angular distributions

•Gamma ray and neutron transport•Locally produced particles•Radon motion

Radiological Modeling

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Comparisons

Measurements CalculationsNear term Objective

Identify any “showstoppers” thatmight interfere with experiment

or facility design Slide provided by Dr. Tom Borak, CSU

Goal: Characterize and Quantify the Radiological Environment

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Muons

Muo

ns/(

m2 s

r yr

)

Overburden (mwe)

Central

Midway

Lower

Upper 2500-3300 mweCentral 6750 ft 4200 mweMidway 5825 ft 5100 mweLower 4950 ft 6000 mwe

• Current LabsMuon flux vs. Overburden

UpperUpper campus8100 Shop 2500 mwe7700 Shop 2900 mwe7500 Level 3300 mwe

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Some Specific Examples of DU Support

Background Sources Characterized Input to modeling tools

Maintain database

Model Background Suppression Shielding Design (passive and active)

Detector Response Simulation tool

3-D model of the overburden

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Sources of background

Neutrons and gammas from radioactivity in rock: U/Th/K.Neutrons, gammas, alphas and betas from radioactivity in detector components (including shielding).Neutrons produced by cosmic-ray muons.Background from radon (special case).Cosmogenic activation.Structural material activation

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The DU Working Group GoalsCompile existing simulations of various types of background in underground laboratories and compare the results from different MC codes with each other

Compare measurements of neutron, gamma fluxes, spectra, etc. with codes.

Investigate methods of background suppression and rejection (passive shielding, active vetoes etc.); help formulate requirements for shielding and veto systems

Calculate expected background rates in detectors

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Muons & neutrinos from cosmic raysBESS and AMS have improved knowledge of the GCR fluxesCalculations of atmospheric neutrinos

Barr et al., astro-ph/0403630

Honda et al., astro-ph/0404457

Interaction physics modelsCORSIKA, NUCRIN, FRITIOF, DPMJET-III, FLUKA, etc.

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Background Source Term Evaluation

For example neutron and gamma production in U/Th decay chainsSoftware: SCALE5.1/ SOURCES-4A (Wilson et al. SOURCES4A, Technical Report LA-13639-MS, Los Alamos, 1999) - code to calculate neutron flux and energy spectrum arising from U/Th contamination in various materials.

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Particle Transport Through the Rocks and Shielding

MCNPX is a general-purpose Monte Carlo radiation transport code for modeling the interaction of radiation with everything. MCNPX stands for Monte Carlo N-Particle eXtended. MCNPX is fully three-dimensional and time dependent. It utilizes the latest nuclear cross section libraries and uses physics models for particle types and energies where tabular data are not available

Geometry can also be done with a code such as GEANT4.

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Demo- Modeling DescriptionNeutron Background Evaluations within Ordinary Concrete Room

Soil

Air

Concrete

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Geometrical Assumptions

Room 4 m x 4m x 4m Concrete 1 ft thickness, = 2.35 g/ccSoil SiO2 = 2.33 g/cc

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Results - ExampleNeutron Spectrum Shift

1.00E+00

1.00E+01

1.00E+02

1.00E+03

1.00E+04

0 2 4 6 8 10 12 14 16 18 20

Energy (MeV)

Source Spectrum Neutron Spectrum Inside the Room

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Innovative Shielding Design

Z. Shayer and R. C. Amme “ Low-Cost Radiation Shielding Material Using Recycled Rubber and Metal Powder” U.S. Patent Application 60/577,441 (2004)Z. Shayer and R. C. Amme “ Dual Purpose Effective Radiation Shielding Material for Space Mission Applications” Proceeding of the Space Nuclear Conference 2005, San Diego, CA June 5-9, 2005, Paper 1128

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DU Experience in Cosmic Rays, Physics of Radiation Transport, and Code Design

Primary cosmic raysJonathan Ormes

Particle Transport Theory and ModelingZe’ev Shayer

Dependable, evolvable software, distributed networked computing architectures, databases and graphical information systems

Anneliese Andrews and colleagues

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Plan for DU Support to HUSEP

Assist “Low background group” for S2 proposal with “toy model” of radiation transport from the surrounding rock and simulate proposed shielding (2005)NSF proposal for more detailed simulation of cosmic ray background (2006)Create detailed modeling tool for simulating the instrumental response to the radiological environment (2007-2009)

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Backup charts

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MCNPX Capabilities

PhysicsTransport 34-particle types at nearly all energies by mixing and matching of nuclear data and model physicsPhysics Models includes; LAHET, FLUKA, Bertini, HETC, Isabel, CEM2k, INCL4/ABLA, MCNP5 and moreLight-ion recoil; Inline generation of double differential cross-sections and residual (MCNPX can produce and track ions created by elastic recoil from neutrons and protons); Photon Doppler broadening; Weight-window generator and exponential transform for model physics:

Source SpecificationsMultiple source particle types; repeated structures sources-path specification; Positron sources; sources on cylindrical surfaces, etc..

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MCNPX Capabilities

Tally Specifications Surface Current; Average surface flux; Average cell flux; Flux tally at point and ring detector; default dose specification; Pulse-high tallies with variance reduction; Residual nuclei tally; Proton reaction and photonuclear reaction multipliers: Expended radiographic tally, etc..

Variance Reduction TechniquesPopulation Control Methods

Geometry splitting and Russian roulette; Energy splitting/roulette; Weight cutoff; Weight Windows and moreModified Sampling Methods

Exponential transform; Implicit capture; Forced collisions; Bremsstrahlung biasing; Source direction and energy biasing; neutron induced photon production biasingPartially Deterministic Methods

Point and Ring detectors; DXTRN spheres; Correlated sampling.

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MCNPX Capabilities

GraphicsMesh tallies (tally grid superimposed over geometry); 2-D color tally contour for lattice and radiography; Geometry plot of WWG superimposed mesh; cross-section data plots.

Parallel ProcessingDistributed memory multiprocessing for all particles and energies.Message passing interface (MPI) multiprocessing.

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Neutron Sources10 point sources distributed randomly within the soil

Watt fission spectrum(,n) Histogram Energy Spectrum(,n) Discrete or Histogram

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Tally Specification - ExampleNeutron and Secondary Photons

Average # of particles and spectrumDose Rate (mrem/hr)Heat deposition within the room due to radiation (in concrete and air)Germanium detector response at various locationsEtc…..

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Computing Facility at DU

A Network of 20 Sun WorkstationsCluster 1: 5 Sun Blade/100’s (500 MHz Ultrasparc 2-e processor and 256 Mb of RAM)Cluster 2: 5 Ultra 5’s (333 MHz Ultrasparc 2-i processor and 128 Mb of RAM)Cluster 3: 10 Ultra 10’s (300 MHz Ultrasparc 2-i processor and 128 Mb of RAM)

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Computing Facility at DU

High-speed Ethernet

cluster3

cluster2

cluster1

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Near Term Task

Toy model of Neutron and Gamma Background at Site (Chemical Composition Data of the Rocks) spontaneous fission, U-238 (U/Th traces in the Rock) (,n) reaction on light elements (O, Al, etc.)

Fast Cosmic muons (negligible ?)Comparison Between Modeling and Measurements (SCALE5.1/MCNPX and Measurements)

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Computer Science Tasks

Data Acquisition and Sensor Network

Dr. Hyunyoung Lee

Spatial Temporal DatabaseDr. Mario Lopez and Dr. Seon Ho Kim

Geographical Information System (GIS)

Dr. Mario Lopez

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Computer Science TasksGeometric Modeling

Dr. Mario Lopez

High Performance Distributed Simulation

Dr. Hyunyoung Lee, Dr. Mario Lopez, and Dr. Seon Ho Kim

Dependable, Evolvable SoftwareDr. Anneliese Andrews and Dr. Hyunyoung Lee

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Computer Science Faculty Expertise

Dr. Anneliese AndrewsDependable, evolvable softwareComponent-based software design

Dr. Seon Ho KimLarge storage systemMultimedia serversSpatial temporal databaseHigh performance computing

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Computer Science Faculty ExpertiseDr. Hyunyoung Lee

Sensor networkParallel and distributed computingHigh performance distributed simulationDependable computing

Dr. Mario LopezGeographical information system (GIS)Spatial temporal databaseHigh performance distributed simulationGeometric modeling

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Areas of DU Expertise Related toHUSEP

Cosmic Rays SimulationSoftware DevelopmentParallel Processing Algorithm and DesignShielding Design and AnalysisRadiological dose assessmentSoftware Quality assuranceMaterials engineeringProbabilistic safety assessment