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Molspin Shielded Alternating Field Demagnetizers


Shielded AF Demagnetizer

The MOLSPIN shielded demagnetizer enables demagnetization of specimens in peak fields up to 1000 Oersteds (.1T). The unit has a two axis tumbler and can accommodate cylindrical samples up to 1" long and 1" diameter. The coil assembly and sample are housed inside a triple walled mu-metal bucket shield. Total power consumption is only 700 watts so the unit can be used without any special power provisions.

The electronics are of novel design whereby the field is both created and changed in a digital manner. This allows the decrease in field to take place only when the field is crossing the axis. The two-axis tumbler ensures that all parts of the sample are subjected to the demagnetizing field. For users particularly concerned with rotational remanent magnetization, the unit is available with a tumbler reversing option which reverses the direction of the tumbler every 2, 4, or 8 rotations.

Tumbler Reversing Option

The two axis tumbler normally rotates in one direction but an option is available that allows the rotation to be reversed after a predetermined number of rotations.



High Field Shielded Demagnetizer

A breakthrough in isolating the coil from the magnetic shield together with extensive re-design of the power supply and power amplifier has allowed the maximum field to be increased to at least 1500 Oersteds.

It has a cooling system and includes reversal of the rotation as standard. The sample size is unchanged at 2.54cm diameter and 2.54cm long.

Although the appearance size is the same as the original (which is still available) the weight is greater. The P.A R.M and A.R.M attachments remain the same.



Optional Features

PARM Attachment

parm.jpg (8008 bytes) A new Molspin device that can be added to the shielded demagnetizers allows Partial Anhysteretic Remanent Magnetization procedures to be performed. The new device is attached to the Shielded Demagnetizer by way of a 5-way plug. All demagnetizers supplied after 31 March 1996 have the 5-pin socket installed and so are "PARM" ready. Older demagnetizers can be modified to take the new socket.


The PARM device has two 10 turn potentiometers fitted with counting dials. One of them defines the field at which the PARM field will come on, the other the field at which the PARM field goes off. This flexible system allows the place and range of the PARM field to be set anywhere on the demagnetizing cycle.

The value of the PARM field (up to one Oersted) is set on a meter. The field only comes on during the reducing phase of the demagnetizing cycle. However a switch allows the field to remain on for the whole cycle if this is desired. In this mode the PARM device becomes a standard ARM device.

ARM Attachment

As well as the PARM device there is also an ARM attachment. This consists of the same coil as the PARM device that is placed within the demagnetizing coil and which can produce a constant field of up to one Oersted.



Please contact ASC Scientific at for current prices.

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