Lines 2-36 were replaced by lines 2-63 |
- partly by PSI, Risø, MaNEP and SNF. 14.9 Tesla is the maximum |
- field achievable with nowadays technology for a split pair coil (which |
- is needed for wide angle access). This limit could in principle be |
- increased to 17.5 by means of a dysprosium insert for small samples. |
- This option is not (yet) available at SINQ. |
- |
- !Specifications |
- ||Magnet |
- |field at sample |14.9 Tesla |
- | " without lambda stage|13.5 Tesla |
- |operating current for 14.9 T|120 A |
- |maximum allowed vertical and horiontal magnetic forces|1000 N |
- |homogeneity over a 10 mm diameter sphere|0.5% |
- |field stability in persistent mode|0.01 % / hour |
- ||Dimensions |
- |diameter of sample space|20 mm |
- |max. useable sample height|20 mm |
- |split access angle|+- 2 deg |
- |sample height for +-2 deg access(visible by neutrons) |14 mm |
- |horizontal access angle|> 330 deg |
- |distance from base of cryostat\\to scattering plane|240 mm |
- |total weight including cryogens|650+-30 kg |
- |total radial aluminium window thickness|43.4 mm |
- |total radial aluminium in entrance window|8.6 mm |
- |entrance window size (radiussed corners 3 mm)|15 x 15 mm |
- |useable LHe capacity|55 l |
- |LHe boil off (static mode)|<350 cc/hr |
- |LN2 capacity|60 l |
- |typical LN2 boil off|600 cc/hr |
- |diameter for transfer tube|12 mm |
- |temperature range (no field dependend limitations)|1.6 ... 300 K |
- |temperature stability|+- 0.1 K |
- |automatic needle valve control only above|3 K |
- |exchange gas needed in sample space (measured at RT)|<15 mbar |
- |sample space diameter above magnet|49.5 mm |
+ partly by |
+ * [PSI|http://www.psi.ch] |
+ * the [Carlsberg Foundation|http://www.carlsbergfondet.dk/] |
+ and the Danish National Science Foundation (danish: [FNU|http://www.forsk.dk]) |
+ * [MaNEP|http://www.manep.ch] |
+ * [SNF|http://www.snf.ch] |
+ |
+ [ma15d.jpg] |
+ |
+ 14.9 Tesla is the maximum field achievable with nowadays technology |
+ for a split pair coil (which is needed for wide angle access). This |
+ limit could in principle be increased to 17.5 by means of a dysprosium |
+ insert for small samples. This option is not (yet) available at SINQ. |
+ |
+ A rotatable sample stick has been made at PSI using a similar design at the |
+ ILL. This allows to leave the magnet in a fixed omega position and to |
+ turn the sample orientation within the magnet. |
+ |
+ !Restrictions |
+ |
+ __after several quenches, operation above 12.5 without lambda stage is not recommended [see|http://samenv:8080/sample_environment/61]__ |
+ |
+ Due to force limits, restrictions are defined for the use of MA15. |
+ ||Instrument ||Allowed Max. Field [[Tesla] |
+ |RITA-2 |11.5 ... 14.9, see [MA15 Rita Restrictions] |
+ |TASP |14.9, see [MA15 TASP Restrictions] |
+ |EIGER |13, see [MA15 Eiger Restrictions] |
+ |ZEBRA |14.9 for the longer distance as defined for MA15 |
+ On all other instruments, MA15 can not yet be used. |
+ |
+ [Specifications / Ramp Limits|MA15Specifications] |
+ |
+ More information on intranet page (Drawing): [LdmWiki:MA15] |
+ |
+ [Omega Motor Change on Rita2] |
+ |
+ [Cooldown Procedure|MA15Cooldown] |
+ |
+ !Pending Issues |
+ |
+ * The automatic needle valve does not always work properly. |
+ A mechanical problem was solved by Oxford Instruments. |
+ It is still a problem that sometimes the needle valve bar |
+ gets frozen. This problem might be avoided when keeping warm |
+ the top of the needle valve during fill. However, at high |
+ fields, the air dryer might not work! |
+ |
+ * The nitrogen level gauge does not work. This has to be fixed, but |
+ it seems that it may appear often. |
+ |
+ * During He-fill, LN2 has to be filled again in order to avoid |
+ air sucking into the LN2 dewar. |
+ |
+ * In order to be used possibly on other instruments, the instruments have to be |
+ checked for magnetic materials around the sample table. After some force |
+ tests, and after eventual modifications of the instrument, the conditions |
+ for a safe operations have to be defined. The next candidate for these |
+ tests is TASP. |
+ |
+ [ma15b.jpg] |
+ [ma15a.jpg] |
+ [ma15c.jpg] |