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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 even-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 are developing a constantly rotating sample device that removes the deadtime associated with moving. For optimal samples, the continuous data collection and sample rotation can result in a double neutron count duty cycle.
We have recent experience adding a CHRNS: Cryogenic Goniometer to NICE and the motor control system, VIPER, was also updated to be compatible with time-stamps giving confidence in a swift incorporation of this device into the experiment control and data acquisition procedures.
System: Rotation Stage for 100mm ILL Cryostat
The rotation system consists of:
- rotation stage to be mounted on top flange of the 100mm ILL cryostat
- rotatable sample stick to be inserted in 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 allowed within sample position, up to 1000mm above sample position
- Sample stick material: 316 SS
- Sample stick shall be ‘very stiff’ to avoid twist while rotation
- The stick should be designed for continuous rotation back and forth with >1 year between service/failure
- Calibrated, 1.4K– 300K, 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 shall be easily removable from the cryostat for sample change without removing the rotation stage mounted on top flange of the cryostat
- Rotation system shall provide vacuum in the sample well of the cryostat, leak rate shall be better than 1e-8 mbar/lt sec
Contacts
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(301) 975-5134