The IN16B spectrometer at ILL has been upgraded with a new variable focusing guide, designed to enhance neutron flux at the sample position and improve energy resolution in backscattering spectroscopy. The horizontal variable focusing guide directs neutrons onto the Phase Space Transformation (PST) chopper. Adjusting the guide geometry helps match the beam phase space to the chopper’s acceptance, improving flux and resolution.
Technical highlights
- Segmented Design (3 sections)
– Upstream of the PST chopper: 4.5 m
– Between PST chopper and Doppler drive: 0.8 m
– Downstream of the PST chopper: 4.5 m
This modular layout enables precise control over beam shaping along the entire flight path. - Motorized Adjustment System
A total of 16 motorized actuators allow adjustment of the guide width, enabling fine-tuning of the neutron beam’s phase space to match specific experimental requirements. - Collision-Safe Mechanism
The mechanical design couples adjacent guide elements, preventing collisions and avoiding configurations that could lead to excessive irradiation or mechanical stress. - High-Precision Positioning
Stepper motors combined with a dedicated guiding system provide positional accuracy of approximately 0.05 mm, ensuring reliable and repeatable guide geometry adjustments. - Fixed Vertical Aperture
The guide maintains a constant height of 120 mm.
