[ Identification | Description | Input parameters | Links ]

# The `ILL_H8_IN1` Instrument

Hot neutron three-axis spectrometer IN1@ILL

## Identification

- Site: ILL
- Author: Emmanuel Farhi
- Origin: ILL (France)
- Date: 2006

## Description

    IN8 is installed on beamtube H10 (diameter F = 200 mm).

    IN1 works in a time-sharing mode. This means that the same monochromator is
    also used by the Be-filter spectrometer IN1-BeF and by the liquids
    diffractometer D4. Changing over between the three different instruments can be
    done without difficulty in about two hours.

    The monochromator unit carries three different vertically focussing
    monochromators built from copper single crystals (available reflecting planes
    Cu(200), Cu(220) and Cu(331)). The exchange of the monochromator planes is
    controlled by the instrument computer. The radius of curvature can be
    automatically adjusted as function of reflected energy in order to maintain
    maximal flux at the sample position in the course of energy scans. The
    scattering angles on the monochromator cover a range of 10<2theta_m <90
    allowing for scanning neutron energies from 13 meV to more than 1 eV..

    The IN1-TAS spectrometer: the scattering angles at the sample and the analyser
    can be changed in the intervals -115<2theta_S<115 and -120<2theta_S<120. Three
    different analysers (PG(002), Cu(200), Cu(220)) can be installed in order to
    optimise intensity and resolution for a given experiment. Various resonance
    absorption filters (e.g. Er, Sm, Hf ...) can be used to suppress higher order
    contaminations from the incident beam or in the scattered beam. An oriented
    Pyrolytic Graphite filter is designed for experiments eventually demanding
    thermal neutron energy range.

    In this TAS configuration, Cu220 are used as monochromator and analyser,
    with a single type detector.

## Input parameters

Parameters in boldface are required; the others are optional.

Name | Unit | Description | Default
KF | Angs-1 | Outgoing neutron wavevector | 10
KI | Angs-1 | Incoming neutron wavevector | 0
QM | Angs-1 | Wavevector transfer in crystal | 0.5
EN | meV | Energy transfer in crystal | 0
verbose | 1 | print TAS configuration. 0 to be quiet | 1
WM | m | Width of monochromator | 0.18
HM | m | Height of monochromator | 0.20
RMH | m | Monochromator horizontal curvature, 0 for flat, -1 for automatic setting | -1
RMV | m | Monochromator vertical curvature, 0 for flat, -1 for automatic setting | -1
DM | Angs | Monochromator d-spacing | 1.278
NHM | 1 | Number of horizontal slabs composing the monochromator | 15
NVM | 1 | Number of vertical slabs composing the monochromator | 15
WA | m | Width of analyzer | 0.16
HA | m | Height of analyzer | 0.12
RAH | m | Analyzer horizontal curvature, 0 for flat, -1 for automatic setting | -1
RAV | m | Analyzer vertical curvature, 0 for flat, -1 for automatic setting | -1
DA | Angs | Analyzer d-spacing | 1.278
NHA | 1 | Number of horizontal slabs composing the analyzer | 15
NVA | 1 | Number of vertical slabs composing the analyzer | 15
L1 | m | Source-Monochromator distance. Contains 1st Collimator of length 5.34 | 7
ALF1 | arc min | Horizontal collimation from Source to Monochromator | 120
ALF2 | arc min | Horizontal collimation from Monochromator to Sample A | 120
ALF3 | arc min | Horizontal collimation from Sample to Analyzer | 120
ALF4 | arc min | Horizontal collimation from Analyzer to Detector | 120
BET1 | arc min | Vertical collimation from Source to Monochromator | 120
BET2 | arc min | Vertical collimation from Monochromator to Sample A | 120
BET3 | arc min | Vertical collimation from Sample to Analyzer | 120
BET4 | arc min | Vertical collimation from Analyzer to Detector | 120

## Links

- Source code for `ILL_H8_IN1.instr`.
- Rescal for Matlab at http://www.ill.eu/instruments-support/computing-for-science/cs-software/all-software/matlab-ill/
- Restrax at http://omega.ujf.cas.cz/restrax/

[ Identification | Description | Input parameters | Links ]