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McStas: ESS_IN5_reprate

[ Identification | Description | Input parameters | Links ]

The ESS_IN5_reprate Instrument

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


  • Site: ESS
  • Author: Kim Lefmann (, Helmuth Schober, Feri Mezei
  • Origin: ESS
  • Date: September 20, 2006


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.
LminAAMinimum wavelength emitted by the moderator4.9
LmaxAAMaximum wavelength emitted by the moderator5.1
lambda0AATarget wavelength for the monochromating crystal5
Pulse_widthsLength of the long pulse. Default to 2 ms.2.857e-3
Num_pulses1Number of pulses to simulate. Default 1.1
GUI_startmDistance from moderator to guide start2.0
FO1_DISTmDistance from moderator to FO1 chopper6
L_ballistic_beginmLength of expanding ballistic section in the beginning of the guide19.5
L_ballistic_endmLength of compressing ballistic section in the end of the guide17
LengthmTotal length of spectrometer (moderator to F2)100
SAMPLE_DISTmDistance from F2 to sample1.2
DETECTOR_DISTmLength sample-detector4
GUI_hmHeight of guide opening at entry0.105
GUI_wmWidth of guide opening at entry0.1
GUI_GAPmGap between guides due to chopper hardware0.05
H1mHeight of guide elements0.167
W1mWidth of guide elements0.116
H2mHeight of guide elements0.185
W2mWidth of guide elements0.15
H3mHeight of guide elements0.19
W3mWidth of guide elements0.15
H4mHeight of guide elements0.213
W4mWidth of guide elements0.14
H_chopmHeight at F2 chopper position0.075
W_chopmWidth at F2 chopper position0.03
H_endmHeight of guide opening at exit0.042
W_endmWidth of guide opening at exit0.0215
ALPHAmParameter for supermirrors in guides, Swiss Neutronics best at 3.43.4
M1Parameter for supermirrors in guides, Swiss Neutronics best at 43.5
F_slow1HzFrequency of the FO1 chopper16.6667
F_slow2HzFrequency of the FO2 chopper0
F_fast1HzFrequency of the F1 chopper0
F_fast2HzFrequency of the F2 chopper200
N_fast1Number of symmetric openings in the fast F choppers1
SLOW1_THETAdegOpening angle of the FO1 chopper120
FO31Inverse frequency of FO3 chopper (if 1, same as F2; if 2, half of F2, etc.)1
THETA_fast1degOpening angle of the F1 chopper180
FAST_THETAdegOpening angle of the F2 chopper5
GammameVWidth of sample quasielastic scattering (0=elastic)0
EtunmeVTunneling energy1
V_HOLEmRadius of hole in V sample (must be smaller than the outer radius: 0.01)0
FRAC_QUASIEL1Fraction of the sample that scatters quasielastically0
FRAC_TUNNEL Fraction of the sample that scatters on the tunneling peaks0
TTdeg2Theta (or a4) scattering angle50
RES_DEmeVAdjustable zoom for energy monitor at detector position0.5
cold Fraction of neutrons emitted from the cold moderatorx0.95


[ Identification | Description | Input parameters | Links ]

Generated on 2023-09-19 20:01:36

Last Modified: Tuesday, 16-Apr-2024 20:05:20 CEST
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