max.Force
horizontal | 500N |
vertical | 1000N |
Instrument | Allowed maximum field [Tesla] | Conditions |
---|---|---|
AMOR | 4 | field perpendicular beam |
AMOR | 6.8 | field parallel beam |
RITA-II | 4 ... 6.8 | see below |
SANS-I | 6.8 / 6.2 (full field) | with spin flipper only when field perpendicular to beam |
SANS-II | 6.8 / 6.2 (full field) | |
TASP | 6.8 | see below (A3 does not move > 4 Tesla) |
EIGER | 6.8 / 6.2 (full field) | goniometer removed |
ZEBRA | 6.8 / 6.2 (full field) | L1 = 1500 mm, L2 = 785 mm (1D detector) |
ZEBRA | 5 / 5 | L1 = 1000 mm, L2 = 785 mm (1D detector) |
Goniometer removed.
Provisional force measuremnents on RITA-II have shown that
the operation of MA7 on Rita-II is allowed:
* at a distance of more than 680 mm or a2 angles < 42.7 the analyser tank touches the wall at a4 ~= 45
For any other configuration force tests have to be redone.
How the distance has to be measured.
In this example the distance is around 400 mm.
Provisional force measuremnents on AMOR have shown that the operation of MA7 on AMOR is allowed with a field perpendicular to the beam at least up to 4 Tesla. The distance to the shielding wall between AMOR and SANS-II has to be at least 540 mm, measured from the aluminium window (or about 870 mm to the magnet centre).
Torque Calculations
In general, the forces are not only radial, but also tangential, inducing a torque onto the magnet. For estimating the forces on the fixation, we need to take into account the distance of the fixation points from the coil center.
For MA7, with a mean coil radius of about 100 m and fixation points at about 150 mm for the coil center, we get the following:
Ro: object distance (mm)
phi: angle (deg) between field direction and direction of object, for maximum force on fixation
Fp: force when object on magnet axis (in field direction)
Ft: maximum total force on fixation
Ro | phi | Ft / Fp |
---|---|---|
<600 | 0 | 1.0 |
800 | 20 | 1.04 |
1000 | 27 | 1.13 |
1200 | 32 | 1.25 |
For the distance to the shielding wall we have to add 1/5 of the edge distance for the mean distance of the material that has to be taken into account (870 * 6/5 = 1044 mm).
Measured force at 3.4 Tesla: 180 N.
Extrapolated to 5 Tesla: 390 N.
Factor 1.2 for including torque: 470 N.
With a reasonable security margin, we allow to go up to 4 Tesla.
Goniometer removed.
Beryllium Filter Distance 27 cm (see photo)
Sample table - Monochromator - 73 cm
A2 | a4 | Allowed field |
---|---|---|
-92 < A2 < -41 (Ei=14.7 meV) | <= 119 | 6.8 Tesla |
WARNING: Motor A3 may not move with a field > 4 Tesla
This data is derived from the force test 7. July 2015:
4.8 Tesla, horizontal force 150 N (towards Beryllium filter), vertical force 180 N.
Allowed up to maximum field independend of the field direction.
With spin flipper only when field perpendicualr to beam and in asymmetric mode. Other configurations with spin flipper have to evaluated.
Force measurements (without spin flipper):
field direction | field | horizontal force | vertical force |
---|---|---|---|
parallel to beam | 4.9 Tesla | 80 N | 340 N |
perpendicular to beam | 4.9 Tesla | 110 N | 180 N |
4.9 T perpendicular to beam | 300 N vertical | 140 N horizontal |
4.9 T parallel to beam | 300 N vertical | 60 N horizontal |