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McStas: ESS_IN5_reprate Instrument at ESS

[ Identification | Description | Input parameters | Output parameters | Links ]

The ESS_IN5_reprate Instrument

An IN5 type (cold chopper) multi-frame spectrometer at ESS LPTS

Identification

  • Site: ESS
  • Author: Kim Lefmann (kim.lefmann@risoe.dk), Helmuth Schober, Feri Mezei
  • Origin:ESS
  • Date: September 20, 2006
  • Version: $Revision$

Description

McStas instrument for simulating IN5-TYPE (cold chopper) multi-frame spectrometer at ESS LPTS.
The sample is incoherent with an inelastic tunneling line.


Input parameters

Parameters in boldface are required; the others are optional.
Name Unit Description Default
Lmin AA Minimum wavelength emitted by the moderator 4.9
Lmax AA Maximum wavelength emitted by the moderator 5.1
lambda0 AA Target wavelength for the monochromating crystal 5
Pulse_width s Length of the long pulse. Default to 2 ms. 0.002
Num_pulses 1 Number of pulses to simulate. Default 1. 1
GUI_start m Distance from moderator to guide start 2.0
FO1_DIST m Distance from moderator to FO1 chopper 6
L_ballistic_begin m Length of expanding ballistic section in the beginning of the guide 19.5
L_ballistic_end m Length of compressing ballistic section in the end of the guide 17
Length moderator to F2 [m] Total length of spectrometer 100
SAMPLE_DIST m Distance from F2 to sample 1.2
DETECTOR_DIST m Length sample-detector 4
GUI_h m Height of guide opening at entry 0.105
GUI_w m Width of guide opening at entry 0.1
GUI_GAP m Gap between guides due to chopper hardware 0.05
H1 - -H4: [m] Height of guide elements 0.167
W1 - -W4: [m] Width of guide elements 0.116
H2 0.185
W2 0.15
H3 0.19
W3 0.15
H4 0.213
W4 0.14
H_chop m Height at F2 chopper position 0.075
W_chop m Width at F2 chopper position 0.03
H_end m Height of guide opening at exit 0.042
W_end m Width of guide opening at exit 0.0215
ALPHA m Parameter for supermirrors in guides, Swiss Neutronics best at 3.4 3.4
M 1 Parameter for supermirrors in guides, Swiss Neutronics best at 4 3.5
F_slow1 Hz Frequency of the FO1 chopper 16.6667
F_slow2 Hz Frequency of the FO2 chopper 0
F_fast1 Hz Frequency of the F1 chopper 0
F_fast2 Hz Frequency of the F2 chopper 200
N_fast 1 Number of symmetric openings in the fast F choppers 1
SLOW1_THETA deg Opening angle of the FO1 chopper 120
FO3 if 1, same as F2; if 2, half of F2, etc. [1] Inverse frequency of FO3 chopper 1
THETA_fast1 deg Opening angle of the F1 chopper 180
FAST_THETA deg Opening angle of the F2 chopper 5
Gamma 0=elastic [meV] Width of sample quasielastic scattering 0
Etun meV Tunneling energy 1
V_HOLE must be smaller than the outer radius: 0.01 [m] Radius of hole in V sample 0
FRAC_QUASIEL 1 Fraction of the sample that scatters quasielastically 0
FRAC_TUNNEL 0
TT deg 2Theta (or a4) scattering angle 50
RES_DE meV Adjustable zoom for energy monitor at detector position 0.5
port 30
cold 0.95

Links


[ Identification | Description | Input parameters | Output parameters | Links ]

Generated automatically by McDoc, Peter Willendrup <peter.willendrup@risoe.dk> / Fri Mar 17 20:40:07 2017


Last Modified: Friday, 17-Mar-2017 21:40:07 CET
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