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

The ILL_Lagrange Instrument

IN1-Lagrange hot neutrons spectrometer for liquids at the ILL.

Identification

• Site: ILL
• Author: E. Farhi
• Origin: LLB/ILL
• Date: 13 Apr 2006

Description

IN1-Lagrange hot neutrons spectrometer for liquids at the ILL.

The dedicated liquid and amorphous instrument Lagrange is a spectrometer with
constant final neutron energy, and variable incoming neutron energy.
The analyser is a focusing barrel covered with PG analyser, all focusing to
the detector. The flux is thus very high, and the resolution is that given
buy the PG crystal mocaicity.

The monochromator take-off angle is 2Theta_M ~ 20-25 deg, variable. The available
monochromators are all vertically focusing, Cu (200) for 0.7 Angs, Cu (220)
for 0.5 Angs.

Cu       002 DM=1.807 AA
Cu       220 DM=1.278 AA
PG       002 DM=3.355 AA
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Examples

(Test cases in bold)

• Test: lambda=0.897 Detector: Detector_I=3704.83

Input parameters

Parameters in boldface are required; the others are optional.

Name	Unit	Description	Default
lambda	AA	Wavelength at monochromator	0.897
DM	AA	d-spacing of monochromator	1.807
RV	m	Monochromator vertical curvature, 0=flat, -1=automatic	-1
coh	str	File name for sample coherent scattering contribution	"Rb_liq_coh.sqw"
inc	str	File name for sample incoherent scattering contribution	"Rb_liq_inc.sqw"
L1	m	Source-Monochromator distance	6.35
L2	m	Monochromator-Sample distance	2.55
L3	m	Sample-Detector distance	0.901
verbose	1	Print spectrometer configuration. 0 to be quiet	1

Links

• Source code for ILL_Lagrange.instr.
• The D4 diffractometer at the ILL

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

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Last Modified: Friday, 11-Sep-2026 15:00:09 CEST