[ Identification | Description | Input parameters | Links ]

The FermiChopper Component

Fermi Chopper with rotating frame.



Models a fermi chopper with optional supermirror coated blades
supermirror facilities may be disabled by setting m = 0, R0=0
Slit packages are straight. Chopper slits are separated by an infinitely
thin absorbing material. The effective transmission (resulting from fraction
of the transparent material and its transmission) may be specified.
The chopper slit package width may be specified through the total width 'xwidth'
of the full package or the width 'w' of each single slit. The other parameter
is calculated by: xwidth = nslit*w. The slit package may be made curved and use
super-mirror coating.

FermiChopper(phase=-50.0, radius=0.04, nu=100, yheight=0.08, w=0.00022475, nslit=200.0, R0=0.0, Qc=0.02176, alpha=2.33, m=0.0, length=0.012, eff=0.95)

Apr 2005: extensive external test, most problems solved (cf. 'Bugs')
Validated by: K. Lieutenant, E. Farhi

no absorbing blade width used

Input parameters

Parameters in boldface are required; the others are optional.
phasedegchopper phase at t=00
radiusmchopper cylinder radius0.04
nuHzchopper frequency. Omega=2*PI*nu in rad/s, nu*60 in rpm. Positive value corresponds to a counter-clockwise rotation around y.100
wmwidth of one chopper slit0.00022475
nslit1number of chopper slits200
R01low-angle reflectivity0.0
QcAA-1critical scattering vector0.02176
alphaAAslope of reflectivity2.33
m1m-value of material. Zero means completely absorbing.0.0
WAA-1width of supermirror cut-off2e-3
lengthmchannel length of the Fermi chopper0.012
eff1efficiency = transmission x fraction of transparent material0.95
zero_time1set time to zero: 0=no, 1=once per half cycle, 2=auto adjust phase0
xwidthmoptional total width of slit package0
verbose1set to 1,2 or 3 gives debugging information0
yheightmheight of slit package0.08
curvaturem-1Curvature of slits (1/radius of curvature).0
delayssets phase so that transmision is centered on 'delay'0


[ Identification | Description | Input parameters | Links ]

Generated on 2024-01-03 11:47:43