Radiation Detector - Model 44-9
CE Seal

The GM pancake-type detector in the Model 44-9 is arguably the most popular radiation detector used throughout the world. This detector is sensitive to alpha, beta, and gamma radiation, is enclosed within a rugged metal enclosure, and is conveniently shaped and sized for checking contamination on people and objects.

This detector operates between 850 to 1000 volts, and is compatible with any Ludlum instrument capable of supplying 900 Vdc and an input sensitivity of 30 mV or higher.                         

Similar Models

Model 44-40: uses a lead housing to reduce background
Model 44-9-18: incorporates a gooseneck-type flexible end with an extension handle stretching to 0.9 m (36 in.) length
Flatten the Energy Response
The venerable GM pancake detector has a significant over-response at lower energies that produce false exposure and dose readings. To correct this situation, Ludlum offers simple snap-on filters anytime exposure or dose measurements are required.
Note: The Model 2002-1050 Dose Filters and Model 4002-1066 Exposure Filters are designed to fit Model 44-9 Series of Radiation Detectors with serial number 97000 and higher. Neither filter will fit the Model 44-9-13 or older units unless modified.
Ludlum Measurements offers two energy compensation filters that flatten the energy response of the Model 26 to facilitate measuring either the exposure rate or the ambient dose equivalent rate. The filters flatten the response to within ±20% referenced to 137Cs (662 keV) over an energy range of 33 keV to 1.2 MeV for exposure and down to 20 keV for ambient dose equivalent.

Energy Compensation Filter Products

Model 26 Integrated Frisker series
Model 26-1 DOSE: Model 26-1 with snap-on Exposure Filter (PN 48-4007)
Model 26-1 EXP: Model 26-1  with snap-on filter and replacement screen (PN 48-4006)
Model 44-9 GM Detector series
Model 44-9DOSE: Model 44-9 detector with snap-on Exposure Filter (PN 47-3789)
Model 44-9EXP: Model 44-9 detector with snap-on Dose Filter and replacement screen (PN 47-3788)
Filter Kit Modification for Model 26-1 and Model 44-9 instruments
Ambient Dose Equivalent Filter: kit includes snap-on filter and replacement screen (PN 2002-1050)
Model 26 Exposure Filter Kit: includes snap-on Exposure Filter for Model 26 series (PN 4498-334)
Model 44-9 Exposure Filter Kit: includes snap on Exposure Filter for Model 44-9 series (PN 4002-1066)