1 University of Denver Presented to Henderson DUSEL Collaboration meetings, Nov , 2005 Jonathan F. Ormes, Ze’ev Shayer, Anneliese Andrews

2 DU science facilities in Clear Creek County Mt.Evans summit – 4,300 meters altitude, paved highway, 15 air-miles from Henderson Cosmic 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

3 Potential synergies?: Mt. Evans and HUSEP Joint outreach effortsContemporaneous particle measurements Info and details: Jon Ormes/Bob Stencel

4 DU Plan Model the radiation environment for DUSEL proposals Design for low background test lab

5 Simulation tool for experiment developers Match to background measurements Evolves to full 3-d spatial model of the mine and overburden

6 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

7 Comparisons MeasurementsCalculations  Near term Objective Identify any “showstoppers” that might interfere with experiment or facility design Slide provided by Dr. Tom Borak, CSU Goal: Characterize and Quantify the Radiological Environment

8 Muons Muons/(m 2 sr yr) Overburden (mwe) Central Midway Lower Upper mwe Central 6750 ft 4200 mwe Midway 5825 ft 5100 mwe Lower 4950 ft 6000 mwe Current Labs Muon flux vs. Overburden Upper Upper campus 8100 Shop 2500 mwe 7700 Shop 2900 mwe 7500 Level 3300 mwe

9 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

10 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

11 The DU Working Group Goals Compile 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

12 Muons & neutrinos from cosmic rays BESS and AMS have improved knowledge of the GCR fluxes Calculations of atmospheric neutrinos Barr et al., astro-ph/ Honda et al., astro-ph/ Interaction physics models CORSIKA, NUCRIN, FRITIOF, DPMJET-III, FLUKA, etc.

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

14 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.

15 Demo- Modeling Description Neutron Background Evaluations within Ordinary Concrete Room Soil Air Concrete

16 Geometrical Assumptions Room 4 m x 4m x 4m Concrete 1 ft thickness,  = 2.35 g/cc Soil SiO 2  = 2.33 g/cc

17 Results - Example Neutron Spectrum Shift Source Spectrum Neutron Spectrum Inside the Room

18 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

19 DU Experience in Cosmic Rays, Physics of Radiation Transport, and Code Design Primary cosmic rays Jonathan Ormes Particle Transport Theory and Modeling Ze’ev Shayer Dependable, evolvable software, distributed networked computing architectures, databases and graphical information systems Anneliese Andrews and colleagues

20 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 ( )

21 Backup charts

22 MCNPX Capabilities Physics Transport 34-particle types at nearly all energies by mixing and matching of nuclear data and model physics Physics Models includes; LAHET, FLUKA, Bertini, HETC, Isabel, CEM2k, INCL4/ABLA, MCNP5 and more Light-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 Specifications Multiple source particle types; repeated structures sources-path specification; Positron sources; sources on cylindrical surfaces, etc..

23 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 Techniques Population Control Methods Geometry splitting and Russian roulette; Energy splitting/roulette; Weight cutoff; Weight Windows and more Modified Sampling Methods Exponential transform; Implicit capture; Forced collisions; Bremsstrahlung biasing; Source direction and energy biasing; neutron induced photon production biasing Partially Deterministic Methods Point and Ring detectors; DXTRN spheres; Correlated sampling.

24 MCNPX Capabilities Graphics Mesh 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 Processing Distributed memory multiprocessing for all particles and energies. Message passing interface (MPI) multiprocessing.

25 Neutron Sources 10 point sources distributed randomly within the soil Watt fission spectrum ( ,n) Histogram Energy Spectrum ( ,n) Discrete or Histogram

26 Tally Specification - Example Neutron and Secondary Photons Average # of particles and spectrum Dose Rate (mrem/hr) Heat deposition within the room due to radiation (in concrete and air) Germanium detector response at various locations Etc…..

27 Computing Facility at DU A Network of 20 Sun Workstations Cluster 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)

28 Computing Facility at DU High-speed Ethernet cluster3 cluster2 cluster1

29 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)

30 Computer Science Tasks Data Acquisition and Sensor Network Dr. Hyunyoung Lee Spatial Temporal Database Dr. Mario Lopez and Dr. Seon Ho Kim Geographical Information System (GIS) Dr. Mario Lopez

31 Computer Science Tasks Geometric Modeling Dr. Mario Lopez High Performance Distributed Simulation Dr. Hyunyoung Lee, Dr. Mario Lopez, and Dr. Seon Ho Kim Dependable, Evolvable Software Dr. Anneliese Andrews and Dr. Hyunyoung Lee

32 Computer Science Faculty Expertise Dr. Anneliese Andrews Dependable, evolvable software Component-based software design Dr. Seon Ho Kim Large storage system Multimedia servers Spatial temporal database High performance computing

33 Computer Science Faculty Expertise Dr. Hyunyoung Lee Sensor network Parallel and distributed computing High performance distributed simulation Dependable computing Dr. Mario Lopez Geographical information system (GIS) Spatial temporal database High performance distributed simulation Geometric modeling

34 Areas of DU Expertise Related to HUSEP Cosmic Rays Simulation Software Development Parallel Processing Algorithm and Design Shielding Design and Analysis Radiological dose assessment Software Quality assurance Materials engineering Probabilistic safety assessment