Review for Test#2 1. Work a problem involving charged particle penetration and energy deposition using Table 3.6 data.

Review for Test#2 1. Work a problem involving charged particle penetration and energy deposition using Table 3.6 data.

Review for Test#2 2. List and describe any or all of the 5 neutron source mechanisms discussed in class.. 3. Calculate the neutron yield due to spontaneous fission and/or  (alpha,n) emission.

5. Calculate the gamma ray yield from radioactive sources. Review for Test#2 4. List and describe any or all of the 7 gamma ray source mechanisms discussed in class. 5. Calculate the gamma ray yield from radioactive sources.

7. Define the response function. Review for Test#2 7. Define the response function. 8. Calculate deposited energy from: (1) Isotropic elastic scatter of neutrons or (2) Isotropic inelastic scatter of neutrons

10. Be able to work problems like any of the homework problems. Review for Test#2 9. Discuss (and distinguish) free field flux response functions versus local flux response functions. 10. Be able to work problems like any of the homework problems.

10. Be able to work problems like any of the homework problems. Review for Test#2 9. Discuss (and distinguish) free field flux response functions versus local flux response functions. 10. Be able to work problems like any of the homework problems.

For the MCNP portion of the course, be able to: Review for Test#2 For the MCNP portion of the course, be able to: 1. Construct an SDEF card from a described source's SPATIAL (point, surface, box, sphere, or cylinder shaped) and ENERGY characteristics. I will NOT give you any cheat sheet about the SDEF parameters (ERG, POS, RAD, ...)

Source description variables Commands: POS=Position of a point of interest RAD=How to choose radial point AXS=Direction vector of an axis EXT=How to choose point along a vector X,Y,Z=How to choose (x,y,z) dimensions VEC=Vector of interest DIR=Direction cosine vs. VEC vector Combinations: X,Y,Z: Cartesian (cuboid) shape POS, RAD: Spherical shape POS, RAD, AXS, EXT: Cylindrical shape VEC,DIR: Direction of particle

Volumetric/beam sources Cuboid sources: X,Y,Z=How to choose (x,y,z) dimensions Spherical sources POS=Position of the sphere center RAD=How to choose radial point (usually a distribution using -21 2) Cylindrical sources POS=Position of base of the cylinder AXS=Direction vector of an axis EXT=How to choose point along a vector RAD=How to choose radial point Beam source POS=Position of the source center VEC=Vector of direction of the beam DIR=Direction cosine vs. VEC vector (distirbution or just 1.0)

X axis of a distribution: SI Syntax: Description: The SIn and SPn cards work together to define a pdf to select a variable from. option= blank or Hhistogram =Ldiscrete =A(x,y) pairs interpolated =Sother distribution #’s

Y axis of a distribution: SP Syntax: Description: Specification of y axis of pdf for distribution n. option=blankcompletes SI =-ppredefined function The P values are the y-axis values OR the parameters for the desired function p—and the SI numbers are the lower and upper limits The predefined distribution we will use most often is 21: SIxx rlow rhigh SP -21 exponent

Description of Problem Just using an empty sphere with a source at origin:

Tutorial 2 Code Tutorial 2, base case c Cells * 1 0 -1 imp:n=1 99 0 1 imp:n=0 c Surfaces * 1 sph 0 0 0 10 c Data cards * mode n sdef pos = 0. 0 0 erg=10 f1:n 1 ctme .25 PRINT

Variations ERG: U235 fission neutron spectrum 8 cm cube source centered on (0,0,0) 4 cm spherical source around origin 18 cm (r=1 cm) x-axis cylinder source centered on origin

2. Explain and set up a tally of the F1, F2, or F4 varieties. Review for Test#2 2. Explain and set up a tally of the F1, F2, or F4 varieties.

Particle crossing tally: F1 Syntax: Description: Tally of current integrated over a surface. Prefixing with ‘*’ changes the units—particles to MeV. Like other tallies, the time dependence is inherited from the source—the code doesn’t care. MCNP5 Manual Page: 3-78

Surface flux tally: F2 Syntax: Description: Tally of flux averaged over a surface. Prefixing with ‘*’ changes the units—particles/cm2 to MeV/cm2. MCNP5 Manual Page: 3-78

Cell flux tally: F4 Syntax: Description: Tally of flux averaged over a cell. Prefixing with ‘*’ changes the units—particles/cm2 to MeV/cm2. MCNP5 Manual Page: 3-78

Energy bins: En Syntax: Description: Create energy UPPER ranges from LOW to HIGH MCNP5 Manual Page: 3-96

Review for Test#2 3. Create a response function from provided data (continuous). You may need your calculator for (energy, probability) values.

Response function: DE, DF Syntax: Description: Used to specify a fixed (non-reaction-based) response function of interpolated (DEi,DFi) pairs. Either axis can be linear- or log-based. (A=LIN or LOG…B=LIN or LOG) MCNP5 Manual Page: 3-97 Example: F4:n 31 DE4 LIN 0 1 2 DF4 LIN 10 20 0

ANSI/ANS Dose Response Functions

Using MCNP-Provided Response Functions The alternate use of the FM card is to use energy dependent values that MCNP knows to get the reaction rates that you want; Cross sections for any reaction in any material covered by the libraries (using ENDF MT numbers) Special “dosimetry” cross sections for special purposes Syntax: FM14:x C mat# reaction# x=particle type C=multiplier (negative means times atom-density of mat#--in which case C is generally the negative cell volume) reaction#=any standard ENDF MT # + any of the special reaction values from Table 3.5 of MCNP manual

Review for Test#2 4. Create an energy-independent, unmultiplied, rectangular mesh tally. I will give you enough information to figure out the tally grid: (x,y,z) min values, max values, and number of divisions.

Set up a Mesh Tally This is a mesh of rectangles (you can also do a cylindrical mesh) that the answer will be collected on. This uses the FMESH card, with the following syntax: FMESHx4:n ORIGIN x0 y0 z0 IMESH x1 IINTS nx JMESH y1 JINTS ny KMESH z1 KINTS nz OUT ij where: (x0,y0,z0) is the lower left corner of the mesh (x1,y1,z1) is the upper right corner of the mesh nx,ny,nz tell how many divisions there are in the mesh in the 3 dimensions OUT ij indicates that you want an (x,y) grid of points (for each z level) (You can use other combinations (e.g., jk would give you a (y,z) grid for each x level)

Set up a Mesh Tally (3) Test of FMESH tally c cells 1 0 -1 2 2 1 -11.35 -2 999 0 1 c surfaces 1 sph 0 0 0 1000 2 rpp 50 55 -100 100 -100 100 c data mode p sdef erg=2 pos = 0 0 0 par=2 fmesh4:p origin -500 -500 -1 imesh 500 jmesh 500 kmesh 1 iints 40 jints 40 kints 1 out ij imp:p 1 1 0 m1 82000 1

Tutorial 3 Base Code Tutorial 3, base case c Cells * 1 0 -1 imp:p=1 2 1 -2.702 1 -2 imp:p=1 99 0 2 imp:p=0 c Surfaces * 1 sph 0 0 0 10 2 sph 0 0 0 15 c Data cards * mode p sdef pos = 0. 0 0 erg=10 m1 13027 1 f1:p 1 2 ctme .25 PRINT

Description of Problem A hollow (thick) aluminum ball:

Variations Outer surface current in 0.1 MeV energy increments, 0.05 cosine increments Outer surface flux in 0.1 MeV energy increments Cell flux (in Al) Cell flux with ANSI dose response Dose map