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CHRNS: MACS sample rotator
The MACS rotator mounted on the cryostat.
Status: Operational
The device has been tested with a 100g sample cell.
The device has motor logic installed in to NICE and is driven by the new event-mode capable VIPER system
Principle:
Given that neutron instrument motors and detectors take several seconds to move and reach a stationary state to make the next data point measurable, we developed a constantly rotating sample device that removes the deadtime associated with moving. For optimal samples, continuous data collection and sample rotation can result in an improvement of a factor of two neutron-count duty cycle.
The rotation system consists of:
- Rotation stage mounted to the top flange of the 100mm ILL cryostat
- A rotatable sample stick to be inserted in the 100mm sample well
- Controller, cables
Specs for the rotation system:
- Aperture diameter: 100+ mm
- 360 deg rotation with adjustable rotation limits
- Bi-directional rotation
- Position accuracy at sample position: 0.005 deg
- Backlash at sample position: no more than 0.01 deg
- Axial load capacity results from operation with vacuum in the sample well
- Rotation speed MAX: no less than 2 deg/s
- Rotation speed MIN: up to 0.1 arcmin/s
- Distance from cryostat top flange to sample position: 1192mm
- Nothing magnetic is within sample position, up to 1000mm above sample position
- Sample stick material: 316 SS
- Sample stick is stiff and avoids twist while rotation
- The stick is designed for continuous rotation back and forth with >1 year between service/failure
- Calibrated, 1.4 K– 300 K, Cernox sensor attached at the sample stick bottom end
- Sample mount: 5/16-18 threaded stud
- Heat buffers to allow normal operation of the cryostat down to 1.5K at sample position
- Sample stick is easily removable from the cryostat for sample change without removing the rotation stage mounted on tthe op flange of the cryostat
- Rotation system provides vacuum in the sample well of the cryostat, leak rate is better than 1e-8 mbar/lt sec
Contacts
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(301) 975-5134