Revision as of 12:10, 9 February 2012

THE 9T MAGNET

... is working but this page is under construction :)

First test with 50Amps (~5.7T) worked!

In the picture a threaded rod is attracted by the magnet at 50A.

Operate the Magnet

Power Supply : OXFORD IPS 120-10 (Max.12 Amp @10Volt)
- Software Remote-control: IPS_120-10_v03.vi
- ! Change of Range when increasing the current at ~4.3A, when decreasing at ~3.4A! Don't get scared by the noise :)
Upper Magnet, Connection on window side of cryo. Power-cable are marked red (+) and blue (-).
Persistent current switch:
- Upper magnet - BOX VII, X9:1/4 ,R_Heater(4K)=135 ${\Omega }$ .
- I_Heater=55mA. The TVL-10 is used as current supply.
The region of the experimental platform between the first nuclear stage and the dilution refrigerator is compensated to 5mT when both magnets are at their full field.

After ramping the magnet the magnetized first nuclear stage must be precooled. The temperature dependence varies as T~t^-1/3.
The first nuclear stage was demagnetized by reducing the field in steps by a factor of 2 to a final field of few mT.
Sweep Rate B>0.5T : R=2T/h.
Sweep Rate B<0.5T : decrease by a factor of 2 proportional to the field.

To Power supply: M6 (#13 box wrench, #6 Allen key).
To Upper Magnet: Connection on window side.
To lower magnet: Connection on door side of the cryostat.
AMP-Plug (connected witch BOX VII): Control of persistent current switch, read-out of two Pt-100, heater

@@ Line 37: / Line 37: @@
 * I/B-Conversion: 10A = 1T (? not yet clarified, date: 14.Dec 2011)
 * Sweep Rate: 1 T/h = 10 A/h = 0.167 A/min
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 == Lower Magnet LMM ==
@@ Line 45: / Line 47: @@
 * I/B-Conversion: B(I) = 0.115 T/A * I[A] ,  ( 78.4A = 9T )
 * Sweep Rate: 1 T/h = 8.7 A/h = 0.145 A/min
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