Model 44-9 with Dose Filter - Model 44-9 DOSE
Introduction

Ludlum offers its Model 44-9 GM pancake detector with a removable energy compensation filter that flattens the energy response to facilitate measuring Ambient Equivalent Dose (Sieverts).

As most know, the venerable GM pancake has a significant over-response at lower energies between approximately 20 to 160 keV (see red line on graph below). Any dose measurements taken with an unfiltered GM pancake detector would thus have unacceptable errors at these lower energies. This  filter developed by Ludlum flattens the response to within  ± 20% referenced to 137Cs (662 keV) over an energy range of 20 keV to 1.2 MeV.

 

Energy Graph

 

This filter simply snaps on across the face of the Model 44-9 GM pancake probe whenever this type of measurements is desired. The filter is then easily removed to continue on with measuring contamination (cpm or Bq).

Note: The Model 2002-1050 Dose Filter is designed to fit Model 44-9 Series of Radiation Detectors with serial number 97000 and higher. The filter will not fit the Model 44-9-13 or older units unless modified.

 

Energy Compensation Filter Products

Model 26 Integrated Frisker series
Model 26-1 DOSE: Model 26-1 with snap-on filter (PN 48-4007)
 
Model 44-9 GM Detector series
Model 44-9DOSE: Model 44-9 detector with snap-on Dose Filter (PN 47-3789)
 
Filter Kit Modification for Model 26-1 and Model 44-9 instruments
Ambient Dose Equivalent Filter: kit includes snap-on filter (PN 2002-1050)