MODEL 2G600 AUTOMATIC SAMPLE DEGAUSSING SYSTEM

Features

• High maximum field — 2.5 kOe
• High field uniformity over sample region — 1%
• Provides for manual or computer controlled sample degaussing. Computer control is implemented with a high level command language over an RS232 data link
• Field incrementation at field zero crossings with equal positive and negative field excursions
• Very low treatment induced (spurious) magnetization
• High accuracy magnetic field settings provided by coil current feedback system
• Rate of field increase and decrease and time at maximum field are manually or computer selectable

Applications

• Precision geologic sample demagnetization using tumblers or sequential 3 axis demagnetization
• Material demagnetization to reduce effects of magnetic contamination

Description

The 2G600 Sample Degaussing System is intended to allow automatic degaussing of samples up to 2.5 kOe with a standard air cooled solenoid (Model 2G601). The 2G600 System can be completely controlled by an external computer over a serial RS232 data link.

When used with an automatic sample handler (e.g. Model 2G800) and a rock magnetometer measuring system (e.g. Model 2G760R), a complete sequence of measure and degauss cycles can be completed without removing the specimen from the holder.

The magnetic field amplitude is controlled by a 12 bit electronic attenuator; the attenuator is incremented at zero crossings with a user controlled number (1,2,4 or 8) of full cycles between amplitude incrementation. This ensures that the samples are always subjected to an equal number of equal amplitude positive and negative cycles between attenuator incrementations.

This attenuation technique coupled with the use of very low leakage and low corona AC capacitors and a low distortion power amplifier greatly reduces the production of treatment induced magnetizations. Because the degaussing coils tend to heat up with use, it is necessary to measure and control the coil current to ensure that an accurate and precise peak magnetic field is achieved.

We accomplish this by measuring the voltage drop across a small (0.25 ohm) precision resistor in series with the coil. This permits a magnetic field amplitude accuracy of 1% to be achieved even when very high fields (hence high coil heating) are used continuously.

Options

• Coil options
• Standard solenoidal (2G601S) — 2.5 kOe maximum field
• Transverse split pair (2G601T) — 2.0 kOe maximum field
• Low loss mu metal shield system

Operating Modes
Switch selectable: manual or computer
Maximum field (with 2G601S coil) 2.5 kOe
Peak field amplitude accuracy 1%
Peak field amplitude setability 0.5 Oe
Frequency of operation with 136 Hz 2G601S coil
Rate of field increase or decrease (selectable): Range Oe/sec. f 68 2f 34 4f 17 8f 8.5
Dwell time at maximum field selectable in 1 second increments from 0 to 9 seconds
Size and weight: 5"Hx19"Wx17"D
Control chassis 10 lbs. capacitor and current 10"Hx19"Wx19"D
Feedback chassis 15 lbs. coil (2G601S) 8.6"ODx5.5"L
Cylindrical shape with 3.15" diameter bore sample access 90 lbs. power amplifier 10"Hx19"Wx17"D 75 lbs.
Power requirements 115V @ 1 A or 220V @ 0.5
A control chassis capacitator chassis 115V @ 0.5 A or 220V @ 0.3
A power amplifier 115V @ 20 A or 220V @ 15 A

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