The iCAM/MF moving filter detector head provides iCAM monitor users with an option in filter handling. In place of the fixed, card mounted filter, which must be changed manually at regular intervals, the mechanism passes a continuous belt of filter material under the detector. Hence, when a filter change is required, instead of manual intervention being necessary, the iCAM unit firmware commands the mechanism to step the filter on, presenting a clean piece of filter material to the detector. The length of the filter roll, combined with the ability of the iCAM monitor compensation algorithms to adapt to filter spectrum shape changes, allows up to twelve months operation with no manual intervention in typical applications. This renders the iCAM/MF instrument ideal for use in hazardous or inaccessible areas where frequent personnel access is undesirable, e.g., long term unattended environmental monitoring. It also allows the iCAM monitor to operate in high dust-loading environments, where otherwise frequent manual filter changes would be required.

The sampling head can draw an air sample either directly from the ambient air or remotely via a 1 in. bore hose or pipe connected via the standard iCAM air inlet adaptor.

The mechanism incorporates measurement of the pressure drop across the filter, to assist in determining when a filter change is necessary. The iCAM firmware (V200 or greater) can change the filter on any or all of the following conditions:

• Preset time interval
• Preset air volume
• High filter pressure drop
• Low flow
• High activity
• High radon/thoron background