This system is back from repair and in operation. The only problem is a super-fluid leak in the Lambda
refrigerator that limits the maximum field to 11T instead of 13T. There is also a
3
He insert, which is available for use. Testing has been done to determine maximum fields at the different instruments. You will notice that some of them are fairly low. They are limited due to large forces acting on the magnet. Forces on this magnet are particularly large because it is asymetric and hence has a larger stray field. Contact a member of the
Sample
Environment Team
for more information.
|
Magnet Properties
|
|
Max Field at 4.2K
|
11 T
|
|
Max Field at 2.2K
|
N/A
|
|
Current at 11 T
|
100.719 A
|
|
Field Calibration
|
9.158 A/T
|
|
Max Ramp Rate 0-8.5 T
|
0.8 T/min
|
|
Max Ramp Rate 8.5-10
|
0.2 T/min
|
|
Max Ramp Rate 10-11 T
|
0.04 T/min
|
|
Persistence Switch Current
|
78 mA
|
|
|
Cryostat Properties
|
|
LN
2
Capacity
|
60 L
|
|
LHe Capacity
|
50 L
|
|
Static LN
2
Boil-off
|
0.40 L/hr
|
|
Static LHe Boil-off
|
0.35 L/hr
|
|
Sample Temp. Range
|
1.5-300 K
|
|
3
He Insert Temp. Range
|
0.3-300 K
|
|
*Click
Here for Sample Mounting Info*
|
|
|
Cool Down Info
|
|
LN
2
Pre-Cool Time
|
48 hrs.
|
|
LHe Cool Time
|
4 Hrs.
|
|
LHe Consumption
|
~200 L
|
|
|
Field Limits at Instruments
|
|
BT-7
|
11T
|
|
BT-9
|
4.8T
|
|
SPINS
|
6.4T
|
These are the instruments
where the system has
been tested. For more
information contact Dan Dender.
|
|
New System
After a long trip from Brookhaven National Laboratory (BNL) via England this sytem is finally in service.
We initially received the system on loan from BNL in 2003 only to find a leak into the vacuum jacket.
After being sent to England for repair, where a second leak was found, it is now back and in service. Even
though it is in service we still do not know everything there is to know about this system. As we gain more
experience things will run more smoothly, however, in the begining as with any new item there is a learning curve.
Please plan for this by allowing more time before, during and after your experiment than might normally be expected.
Notes:
- There is no tilt for two reasons: the weight and size are too much for a goniometer to handle safely and the goniometer is removed to make the beam height correct.
- There is no height adjustment on the standard sample stick, but there is on the 3He insert.
- There is a sample stick rotation motor that can be used in favor of rotating the entire cryostat.
- This magnet is asymetric which makes it possible to run a polarized beam of neutrons through it.
More Information:
- 11T Operation Manual (coming soon...)
- 3He Insert Manual (coming soon...)
-
How to Fill Liquid Helium (pdf will open in new window)
Last modified 13-April-2006 by website owner: NCNR (attn: )