Exradin A12S Ion Chamber

Proven guard design yields stable, precise measurements and minimizes settling time by creating uniform field lines
Shell, collector, and guard are made of durable, long lasting Shonka conductive plastic
Use of homogeneous material throughout the chamber minimizes perturbation of the beam due to the presence of the chamber and optimizes measurements
Axially symmetric design of the chamber provides an uniform, isotropic response
Inherent waterproof construction eliminates need for additional protective coverings
Two separate stem pieces of 5.1 cm and 12.7 cm can be coupled together for ease of use
A matching 2.8 mm thick 60Co build-up cap of C552 Shonka air-equivalent plastic is provided for air calibrations and measurements
Additional build-up caps of Delrin and brass are available
Ionization collection efficiency is 99.9% or better
Collecting volume is 0.65 cc

UNCOMPROMISING QUALITY

For absolute dosimetry calibrations in water, air, or other phantom material

DESIGNED FOR ABSOLUTE DOSIMETRY CALIBRATION

Exradin Farmer-type Chambers are specifically designed for absolute dosimetry calibrations in water, air, or other phantom material. The Model A12S thimble chamber is a modified Farmer-Type Chamber Model A12. The collector length of the Model A12S is approximately one-third the size of the Model A12, which confines its collecting volume to more of the tip of the chamber.

FAST, PRECISE MEASUREMENTS

Its waterproof construction and two piece removable stem makes it ideal for use in water phantoms. The chamber vents through a flexible tube that surrounds the triaxial cable, ensuring the collecting volume is in pressure equilibrium with the surroundings. The design assures there are no stem or voltage soakage effects, providing precise and reliable measurements.

DURABLE CONSTRUCTION, BUILT TO LAST

Farmer-type Chambers are constructed of rugged C552 Shonka air-equivalent plastic, providing excellent conductivity and years of reliable use.

Specifications

REF Number	92725
Collecting Volume	0.25 cm³
Nominal Calibration Factor	14 R/nC
Centroid of Collecting Volume	5.8 mm from tip of chamber
Collector Diameter	1.0 mm
Outside Diameter of Shell Collecting Volume	7.1 mm
Wall Thickness	0.5 mm
Shell, Collector, and Guard Material	Shonka air-equivalent plastic C552
Included ⁶⁰Co Buildup Cap	Wall thickness of 2.8 mm; contructed of C552
Venting	Vented to the ambient via the flexible vent tube surrounding the triaxial cable
Stem	1.3 cm OD black phenolic, two-piece with 5.1 and 12.7 cm segments
Nominal Collection Efficiency	1.000
Maximum Polarizing Potential	1000 V
Nominal Inherent Leakage Currents	10^-15 A
Low-Noise Triaxial Cable	50 ohms, 29 pF/ft, 1.5 m long
Signal Connector	Triaxial BNC plug (2-Lug, male pin); others available upon request
High Voltage Connector	Integral with triaxial connector (shell of chamber is common with connector body)
Waterproof	Yes
Product Standards	CE₀₄₁₃, Designed to meet IEC 60601-1, IEC 60731

Model 12s Schematic