[ Identification | Description | Input parameters | Links ]
ILL_IN6 InstrumentIN6 is a time focussing time-of-flight spectrometer designed for quasielastic and inelastic scattering for incident wavelengths in the range of 4 to 6 Angs. An intense beam is extracted from the H15 guide by a vertically focussing monochromator array. It consists of three composite pyrolytic graphite monochromators using the full height (20 cm) of the guide and focussing the beam at the sample position. In order to minimise the interference with the subsequent instruments, the monochromator can deliver only four wavelengths: 4.1; 4.6; 5.1; and 5.9 Angs. The second order reflection from the graphite monochromator is removed by a beryllium-filter cooled at liquid nitrogen temperature. To achieve the time-focussing condition, the beam is pulsed by a Fermi chopper. It has a small slot length to ensure a good transmission. The normal distance between the Fermi chopper and the sample is 38 cm. To prevent frame-overlap when the chopper is rotating faster than 7500 rpm, a suppressor chopper is placed before the Fermi chopper and rotates in phase with the latter. The secondary spectrometer consists first of an evacuated sample area. The detector bank is entirely covered with detector boxes, thus avoiding the inconvenience of moving the counters. This instrument model contains a cold source a triple monochromator (using the GROUP), two Fermi Choppers (including one background chopper), a liquid sample handling coherent and incoherent processes (elastic and inelastic) with multiple scattering, customized monitors, and the SPLIT mechanism to improve the statistics. The H15 guide is not described in this model.
| Name | Unit | Description | Default |
| lambda | Angs | wavelength within 4.14|4.6|5.12|5.92 | 4.14 |
| dlambda | Angs | wavelength HALF spread. default is 0.075 | 0.075 |
| SPEED | rpm | Fermi chopper speed. -1=auto, 0=stopped in open pos. | -1 |
| M1 | coder values | monochromator motor 1 position. -1=auto | -1 |
| M2 | coder values | monochromator motor 2 positinn. -1=auto | -1 |
| M3 | coder values | monochromator motor 3 position. -1=auto | -1 |
| MONITOR | something like time in s | monitor preset | 1 |
| CHA_WIDTH | us | channel width. -1=auto | -1 |
| TOF_DELAY | us | TOF delay. -1=auto | -1 |
| TOF_CHA_RESOL | 1 | number of channels. | 128 |
| ELPEAK | 1 | elastic peak channel. -1=auto | -1 |
| RATIO | 1 | Suppressor speed ratio. -1=no suppressor. | 1 |
| mFC | 1 | super mirror FermiChopper coating m-value | 0 |
| PHASE | deg | Fermi phase w/r/ to Suppressor. -360=auto | -360 |
| Sqw_coh | str | sample coherent S(q,w) file name | "Rb_liq_coh.sqw" |
| Sqw_inc | str | sample incoherent S(q,w) file name | "Rb_liq_inc.sqw" |
| radius | m | outer radius of sample hollow cylinder | 0.01 |
| thickness | m | thickness of sample hollow cylinder | 0.005 |
ILL_IN6.instr.
[ Identification | Description | Input parameters | Links ]
Generated on 2023-09-19 20:01:36