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MA6 vertical field cryomagnet
Restrictions
| Instrument | Field Limit | Comment |
|---|
| DMC | 2.8 Tesla | |
| MARS | 6 Tesla | |
| TriCS | 6 Tesla | |
| PREP | 6 Tesla | in its trolley, far enough from "Kabelkanal" |
| HRPT | 6 Tesla | (measured forces 140 N vertically and horizontally) |
max. Forces on Magnet:
| horizontal | 500N |
| vertical | 500N |
Specifications
Energisation rates (Tesla/min)
| Field range | Training mode (slow) | Normal mode (fast) |
| below 4.8 T | 0.1922 | 0.3844 |
| 4.8 ... 6 T | 0.0641 | 0.3844 |
Main Coils
| Guaranteed maximum central magnetic field | 6 Tesla |
| Current for full field | 93.661 A |
| Homogeneity over 15 mm diameter sphere | 1.0 % |
| Magnet clear bore diameter | 50 mm |
| Nominal inductamce | 18.13 Henry |
| Switch heater current for open state | 65 mA |
| Current decay in persistent mode | < 1/10000 / h |
| Distance of magnetic field centre for base of cryostat | 165 mm |
| Neutron split | 40 mm |
| Vertical neutron access on a 15 mm sphere | ±15 deg |
| Horizontal neutron access | 340 deg |
Resistance values (Ohm)
| | RT | 77 K | 4.2 K |
| Magnet coil | 48.4 | 39.4 | 0.1 |
| Switch heater | 114.7 | 112.5 | 104.5 |
| Spare switch heater | 112.7 | 110.4 | 103.5 |
| Thermometer on coil (Allen Bradley) | 317.5 | 385 | 4560 |
General
| Liquid He evaoration rate (needle vale close, no current) | <275 cm3/h |
| Liquid N2 evaporation rate | 300 cm3/h |
| Useful liquid He volume | 22 l |
| Liquid N2 volume | 25 l |
| Approximate weight | 150 kg |
Pending Issues
Some quenches appeared in 2011, we hope that can be solved by strictly obeying the
training mode ramps.
Solved Issues
The following problems seem to be solved after repair at Oxford Instruments (Aug 2010)
- The magnet seems to have a cold leak, occuring only occasionaly at low temperatures.
As a workaround the main vacuum has to be pumped constantly. (Jul 2009)
- The magnet sometimes quenches (only above 4.8 T)
Attachments:
ma6_homogeneity.png
This particular version was published on 15-May-2012 12:59:08 UTC by MarkusZolliker.
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