Mini 900 Scintillation Monitors
The 900 Series of radiation counters are well established in teaching, research, hospital and industrial laboratories. Their reliability and convenient design are particularly attractive for industrial hygiene applications or where budgets are tight.
Type 41
Sodium iodide crystal 19 mm dia. by 25 mm thick. Suitable for energies from 25 keV upwards. A lead cylinder surrounds the crystal giving the probe directional properties as well as reducing background. Diameter 41 mm Length 220 mm.
Type 41S
Similar to type 41 but without lead shielding and with a larger sodium iodide crystal (25 mm dia. by 38 mm thick) for increased sensitivity. Suitable for energies from 25 keV upwards. The probe is essentially omni-directional for medium and high energy gamma radiation. Diameter 38 mm Length 217 mm.
Type 42A
Sodium iodide crystal 23 mm dia. by 1 mm thick with a 14 mg cm-2 aluminum window. This probe has a higher sensitivity than the Type 41 for gamma energies below 60 keV to a minimum of 10 - 15 keV. An integral lead collimator makes it particularly useful for 125I thyroid monitoring and deep vein thrombosis location. Diameter 40 mm Length 187 mm.
Type 42B
This probe is the beryllium window version of the type 42 and detects very low gamma energies down to 5 keV. The response above 15 keV is almost identical to the 42A.
Type 44A
The sodium iodide crystal (32 mm dia. by 2.5 mm thick) is mounted on the front surface of the probe to facilitate monitoring of large contaminated areas. It is suitable for a range of energies from approximately 15 keV to 250 keV. It is also beta sensitive for energies above 500 keV. Diameter 50 mm Length 180 mm. Aluminum window weight 14 mg cm-˛.
Type 44B
This probe is the beryllium window version of the above and extends the sensitivity down to approximately 5 keV, making it useful for 55Fe.
[3.7 kBq (0.1µCi) of 55Fe at 10 mm yields approx 180 counts s-1.] - Window weight 47 mg cm-˛.
