The `Tunneling_sample` Component

A Double-cylinder shaped all-incoherent scatterer with elastic, quasielastic (Lorentzian), and tunneling (sharp) components.

Identification

Site:
Author: Kim Lefmann
Origin: Risoe
Date: 10.05.07

Description

A Double-cylinder shaped all-incoherent scatterer
with both elastic, quasielastic (Lorentzian), and tunneling (sharp)
components. No multiple scattering. Absorbtion included.
The shape of the sample may be a box with dimensions xwidth, yheight, zdepth.
The area to scatter to is a disk of radius 'focus_r' situated at the target.
This target area may also be rectangular if specified focus_xw and focus_yh
or focus_aw and focus_ah, respectively in meters and degrees.
The target itself is either situated according to given coordinates (x,y,z),
or defined with the relative target_index of the component to focus
to (next is +1).
This target position will be set to its AT position. When targeting to
centered components, such as spheres or cylinders, define an Arm component
where to focus to.

The outgoing polarization is calculated as for nuclear spin incoherence:
P' = 1/3*P-2/3P = -1/3P
As above multiple scattering is ignored .

Example: Tunneling_sample(thickness=0.001,radius=0.01,yheight=0.02,focus_r=0.035,
target_index=1)

Input parameters

Parameters in boldface are required; the others are optional.

Name	Unit	Description	Default
thickness	m	Thickness of cylindrical sample in (x,z) plane	0
radius	m	Outer radius of sample in (x,z) plane	0.01
focus_r	m	Radius of disk containing target. Use 0 for full space	0
p_interact		MC Probability for scattering the ray; otherwise transmit [1]	1
f_QE		Fraction of quasielastic scattering [1]	0
f_tun		Fraction of tunneling scattering (f_QE+f_tun < 1) [1]	0
gamma		Lorentzian width of quasielastic broadening (HWHM) [meV]	0
E_tun		Tunneling energy [meV]	0
target_x		X-position of target to focus at [m]	0
target_y		Y-position of target to focus at [m]	0
target_z		Z-position of target to focus at [m]	0.235
focus_xw		horiz. dimension of a rectangular area [m]	0
focus_yh		vert. dimension of a rectangular area [m]	0
focus_aw		horiz. angular dimension of a rectangular area [deg]	0
focus_ah		vert. angular dimension of a rectangular area [deg]	0
xwidth		horiz. dimension of sample, as a width [m]	0
yheight	m	vert. dimension of sample, as a height	0.05
zdepth		depth of sample [m]	0
sigma_abs		Absorbtion cross section pr. unit cell [barns]	5.08
sigma_inc		Total incoherent scattering cross section pr. unit cell [barns]	4.935
Vc		Unit cell volume [AA^3]	13.827
target_index	1	relative index of component to focus at, e.g. next is +1	0

AT (	,	,		) RELATIVE
ROTATED (	,	,		) RELATIVE

The Tunneling_sample Component

Identification

Description

Input parameters

Links

The `Tunneling_sample` Component