|
|||
|
|
Suggested Environmental Magnetizm Combinations
Molspin equipment usually centres on cylindrical samples 1" (25.4mm) diameter x 1" (25.4mm) long. For Environmental work investigators usually use 10 ml plastic pots with lids. These pots are available from a number of sources but are also available via Molspin Ltd. Molspin has developed a series of holders to take these pots. They are called the environmental set. If the set is ordered at the same time as the apparatus these holders are supplied at the standard cost. The set allows measurements to be made on soil samples of Natural Remanent Magnetizm (NRM), Saturation Isothermal Remanent Magnetizm (SIRM), Isothermal Remanent Magnetizm (IRM) and Anhysteretic Remanent Magnetization (ARM).
Spinner Magnetometer
As a minimum (unless you already have one), you will need a spinner magnetometer. These devices spin the sample in a shielded enclosure within coils to identify the North pole magnetic vector. Molspin's Minispin is designed to work in the field (or in a laboratory) and, when linked to a laptop computer, provides the perfect field research capability. The magnetometer operates continuously for around 8 hours on a single charge and the unit can be recharged from the cigarette lighter in a car/van.
To jump to the datasheet for the Minispin, click here. The large sample Minispin may also be of interest here. However, the large samples (approximately a 2" cube) are not readily interchangeable with the small sample pots.
Demagnetizer
You will need a demagnetizer of one form or another to determine the magnetic grain type and material within the soil sample or to remove secondary magnetizm. There are two options to choose from here being a Field Demagnetizer and a Thermal Demagnetizer. The Field Demagnetizer is better when working with domains whilst the thermal demagnetizer will provide the Curie temperature for the magnetic grains. Each method has its own merits and you should investigate both before choosing the method you wish to adopt (the best laboratories have both methods available to them). Molspin provides a field demagnetizer which tumbles the sample in one axis to ensure maximum secondary maznetizm removal.
Molspin's demagnetizer provides fields of up to 1500 Oersteds (depending upon the version selected). Power consumption is around 700W allowing use from a domestic supply.
To jump to the datasheet for the Demagnetizer, click here.
One of the advantages of a field demagnetizer is the ability to study Anhysteretic Remanent Magnetization where samples are subjected to a small constant DC field in a reducing AC field. If you wish to study this then you will need an ARM unit, the datasheet for which can be found here.
If you are particularly interested in characterising magnetic particles, you could opt for the PARM (Partial Anhysteretic Remanent Magnetizationunit which again provides a small constant DC field for the sample but allows the user to choose the AC field intensity at which the field starts as well as the peak field encountered. The AC field is then reduced and cuts off at the original starting point. The data sheet for the PARM unit can be found by clicking here.
For a thermal demagnetizer, Molspin suggests those made by Magnetic Measurements Ltd which can be found by clicking here. However, the polystyrene pots used here are not suitable containers for use during thermal demagnetization.
Pulse Magnetizer
You will need a pulse magnetizer if you intend to study isothermal remanent magnetization (IRM). These devices provide a large pulse of magnetising field (up to 1 Te) over a very short period (1/100 second). This is achieved using a capacitor bank but has the advantage that the power consumption is around 100W - easily possible from a domestic power supply.
Molspin's pulse magnetizer provides fields of up to 1 Tesla and (depending upon the version selected) down to 0.1 T with precision.
To jump to the datasheet for the Pulse Magnetizer, click here.
Don't forget when ordering to indicate that the equipment is to be used for environmental magnetizm!