The `Tunneling_sample` Component

Modified from: Vanadium sample.

Identification

Author: Kim Lefmann
Origin: Risoe
Date: 10.05.07
Version: 1.3

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, zthick.
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(radius_i=0.001,radius_o=0.01,h=0.02,focus_r=0.035,
          target_index=1)

Input parameters

Parameters in boldface are required; the others are optional.

Name	Unit	Description	Default
radius_i	m	Inner radius of sample in (x,z) plane	0
radius_o	m	Outer radius of sample in (x,z) plane	0.01
h	m	Height of sample y direction	0.05
focus_r	m	Radius of disk containing target. Use 0 for full space	0
frac	1	MC Probability for scattering the ray; otherwise penetrate	1
f_QE	1	Fraction of quasielastic scattering	0
f_tun	1	Fraction of tunneling scattering (f_QE+f_tun < 1)	0
gamma	meV	Lorentzian width of quasielastic broadening (HWHM)	0
E_tun	meV	Tunneling energy	0
target_x	-		0
target_y	m	position of target to focus at	0
target_z	-		0.235
focus_xw	m	horiz. dimension of a rectangular area	0
focus_yh	m	vert. dimension of a rectangular area	0
focus_aw	deg	horiz. angular dimension of a rectangular area	0
focus_ah	deg	vert. angular dimension of a rectangular area	0
xwidth	m	horiz. dimension of sample, as a width	0
yheight	m	vert. dimension of sample, as a height	0
zthick	m	thickness of sample	0
sig_a	barns	Absorbtion cross section pr. unit cell	5.08
sig_i	barns	Total incoherent scattering cross section pr. unit cell	4.935
V0	AA^3	Unit cell volume	13.827
target_index	1	relative index of component to focus at, e.g. next is +1	0

Output parameters

Name	Unit	Description	Default
StructVarsV
VarsV

The Tunneling_sample Component

Identification

Description

Input parameters

Output parameters

Links

The `Tunneling_sample` Component