X-ray detector, Al window 32mm x 2.5mm

Scintillation Probe Type 44A 
The sodium iodide crystal (32 mm dia by 2.5mm 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 15keV to 250keV. It is also beta sensitive for energies above 500keV.

Diameter 50mm Length 180mm. Aluminum window weight 14mg cm^-2.
Sensitivity 3.8, 1.6 & 1.4 counts s^-1 for 1Bq cm^-2 (2.7 x 10-⁵uCi cm^-2) of ¹²⁵I,^99mTc, ⁵⁷Co respectively.
Background 4-8 counts s^-1 depending on locale