Fluke Biomedical 943-35 - Manual (Page 6)

Victoreen 942-35,943-36,943-36H, 943-37,943-237A
Operators Manual
1-2
Model 943-36
The 943-36 Gamma Scintillation Detector consists of an integral 1.5 inch diameter by 1.0 inch thick
sodium iodine (Nal) crystal/photomultiplier tube assembly and preamplifier, enclosed in a stainless steel,
housing. The aluminum crystal housing protrudes through the process end of the detector for maximum
efficiency. The detector is normally used for monitoring of radioactive iodine, or in liquid process monitors,
where the detector is protected from the process by a stainless steel well that is part of the detector shield
assembly. The well is provided separately.
Model 943-36H
The 943-36H is similar in construction to the 943-36, and is modified to operate at process temperatures
of up to 160°F with less than a 10% decrease in output at low photon energies (below 662 keV), and less
than a 5% decrease in output at high energies (662 keV and above). This detector is recommended for
use in applications where the process temperature is above 120°F.
Model 943-37
The 943-37 Gamma Scintillation Detector consists of an integral 2.0 inch diameter by 2.0 inch thick
sodium iodine (Nal) crystal/photomultiplier tube assembly and preamplifier, enclosed in a stainless steel
housing. The stainless steel housing completely encloses the scintillator and is used where direct contact
with the process is required. The 2 inch crystal provides more sensitivity to both ambient and process
radiation than the 943-35 or 943-36 detectors, and is used in applications where low ambient background
radiation is anticipated.
Model 943-237
The 943-237A Americium Detector contains a small capsule of Americium 241, which is inserted in the
sodium iodine (Nal) crystal. The function of the Americium is to provide a high-energy pulse output for
regulation of the high voltage power supply under conditions where fluctuations in the process
temperature are expected, or where pulse height spectrometry is desired. The americium-doped
detectors are designed to be used in conjunction with the 960AM series Americium Regulator Module or
the 942-200-90 SCA/Americium Regulator board for dynamic regulation of the detector high voltage.
Americium 241 is selected as the source of calibrating energy for the regulated detector, because the
equivalent energy level of the pulse (approximately 5.4 MeV) is relatively distant from that of the isotopes
normally being monitored.
1.4 Specifications
The 943 series Gamma Scintillation Detectors have been assembled with parts selected for the high
reliability required in nuclear applications. Unauthorized repairs made to the detector will void the
warranty and may affect the nuclear qualification. The detectors should be returned to Fluke Biomedical
for authorized, qualified (ANSI 45.2.6, Skill Level II) service or repair.
The following detector models are no longer
manufactured, and may be replaced as shown
below.
Obsolete Model Description Replacement
943-38 2 x 2 in crystal, carbon steel housing 943-37
943-238A 2 x 2 in crystal, carbon steel housing, with Americium 943-237A
NOTE