PDR-56F Radiac Set Scintillation Counter

© Brooke Clarke 2013
PDR-56F Radiac Set
          Scintillation Counter

Background
Description
Problems
Manuals
Related
Links

Background

Detectors for radioactivity come in many forms.  The most common are Geiger-Mueller tube based but they are not as sensivitive as the scintillation counter (Wiki) type, like this PDR-56F.

When a radioactive particle hits an atom of the crystal (scintillator) a photon of light is emitted.  The crystal must be in a light tight housing so the only light is from the crystal.  Typically the light is detected by a photomultiplier tube (Wiki). The electrical pulse that comes out of the photomultiplier tube has a pulse amplitude that is proportional to the energy of the particle that generated it.  The PDR-56 is designed to detect the X-Ray (medium energy Gamma Rays (Wiki)) that come from Plutonium 239 (Wiki).  More generalized detectors can be used in Multi-Channel Analyzers (MCA) to display a graph of the energy magnitude vs. energy level thus allowing analysis of radioactive materials.

The PDR-56 might be called a Single Channel Analyzer since the X-Ray (Wiki) probe (DT-590A) is optimized for detecting 239P.

Description

The PDR-56 set consists of the meter and three probes (main, auxiliary and X-Ray) as well as some related items like a storage case, carrying strap and probe extended.

The crystal used for the DT-590A  X-Ray Probe is CaF2(Eu) in order to detect 14-21 keV gamma radiation from 239P.  See the Links below for a modification that uses a NaI(T1) crystal and readjustment of the trim pots so for a general use gamma detector, like for use in an MCA.

The main probe and auxiliary probe share the same 931 photomultiplier tube and are just different sensing crystals.

Fig 1 Radiacmeter w/ Main Probe
PDR-56F Radiac
                  Set Scintillation Counter
Fig 2 Cable (always needed)
PDR-56F Radiac
                  Set Scintillation Counter
Fig 3 Main Probe Telescoping Extension
PDR-56F Radiac
                  Set Scintillation Counter
Fig 4 Carry Strap
PDR-56F Radiac
                  Set Scintillation Counter
Fig 5 H-43B Headphones
NSN: 5965-00-651-7372
CAGE: 96696 Canberra Ind.
PDR-56F Radiac
                  Set Scintillation Counter
Fig 6 DT-228A Aux Probe
PDR-56F Radiac
                  Set Scintillation Counter
Fig 8 DT-590A 239P X-Ray Probe
PDR-56F Radiac
                  Set Scintillation Counter

Fig 9 DT-224B Main Probe
PDR-56F Radiac
                  Set Scintillation Counter

Fig 12 IM-160F Radiacmeter
PDR-56F Radiac
                  Set Scintillation Counter

Fig 13 CY-7375 Storage Case
PDR-56F Radiac
                  Set Scintillation Counter
Fig 14 "D" battery positions
PDR-56F Radiac
                  Set Scintillation Counter
Fig 15 Missing Test Source?
PDR-56F Radiac
                  Set Scintillation Counter
Fig 16 Main Probe opened & DT-228A Aux Probe
931A Photomultiplier tube
PDR-56F Radiac
                  Set Scintillation Counter
Fig 17 Aux Probe on Extension
PDR-56F Radiac
                  Set Scintillation Counter
Handle shows on meter, but when in use is held in the hand
that's not carrying the meter.


Problems

Instead of zeroing on the 10K range the needle is pinned to the right (past full scale), but does zero on the other ranges.

Manuals

TM 11-6665-245-12
TM 11-6665-245-12-HR
TM 11-6665-245-20P
TM 11-6665-245-34
TM 11-6665-245-34P

Related

RADIAC CALIBRATOR SET AN/UDM-7( )
Radiation Detectors
Bicron Surveyor 50
PDR-27
The Polonium Pen (Tech Lib web page)

Links

Home-Built Radiac (Radiation Detector and Meter) for a Surplus DT-590A/PDR-56F Scintillation Probe
Converting a DT-590A/PDR-56F “X-Ray” Probe into a General-Purpose NaI(Tl) Gamma Probe

PRC68, Products for Sale, Alphanumeric index to web pages

This page created 15 Jan 2013