Exradin A2 Ion Chamber

Proven guard design yields stable, precise measurements and minimizes settling time by creating uniform field lines
Shell, collector, and guard are all 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
Additional Cobalt-60 build-up caps of C552, D400, and A150 are available
Ionization collection efficiency is always 99.9% or better
Collecting volume is 0.54 cc

UNCOMPROMISING QUALITY

For relative dosimetry scanning and measuring points in water, air, or other phantom material

A PERFECT BALANCE BETWEEN FAST SCANNING AND POINT DOSE MEASUREMENTS

The Spokas Thimble Chamber permits the precise measurement of exposure and air kerma in photon beams and of absorbed dose in photon, electron, proton, neutron, and mixed photon-neutron beams.

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

The Model 2 Exradin Spokas Thimble Chamber is available in three versions of rugged, Shonka plastic, providing excellent conductivity and years of reliable use:

C552 air-equivalent plastic, Model A2, REF 92718, appropriate for exposure or air kerma
D400 polystyrene-equivalent plastic, Model P2, REF 92720, appropriate for use with a polystyrene phantom
A150 tissue-equivalent plastic, Model T2, REF 92721, appropriate for absorbed dose in either tissue or water

Specifications

REF Number	92718 - A2 92720 - P2 92721 - T2
Collecting Volume	0.54 cm³
Nominal Calibration Factor	6 R/nC
Centroid of Collecting Volume	7.0 mm from tip of chamber
Collector Diameter	4.6 mm
Outside Diameter of Shell Collecting Volume	11.4 mm
Wall Thickness	1.0 mm
Shell, Collector, and Guard Material	A2 - Shonka air-equivalent plastic C552 P2 - Polystyrene-equivalent plastic D400 T2 - Shonka tissue-equivalent plastic A150
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 A2 Schematic