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Ordering Info


The IC-18 is a three terminal 0.1cc cylindrical ionization chamber. It is available in 2 different wall materials; tissue equivalent plastic and graphite. These chambers are used for direct comparison of radiation source strengths, beam monitoring in accelerator facilities, and accurate measurement of absorbed dose at a prescribed experimental point. By using a pair with different wall materials it is possible to measure mixed fields and separate the gamma and neutron components.

The cylindrical detector is mounted on the end of a stem with the signal connections made through a terminal block. The block contains the BNC signal connector and the MHV high voltage connector. The stem effects are less than 1 x 10E-12A for a 1 x 10E4 R/h exposure with Co60. The effect may be minimized by using a + and – collecting voltage on the detector and averaging the readings.

Model Number Chamber Volume Wall Material Wall Thickness Wall Density
IC-18 0.1 CC Tissue Equivalent 0.064 185 mg/cm2
IC-18G 0.1 CC Graphite 0.064 300 mg/cm2

Ionization Chamber: Cylindrical collecting volume; guarded three-terminal design; Tissue Equivalent plastic or graphite wall and collecting electrode; mounted on a 10.5-inch (26.7 cm) long aluminum stem; built in gas flow provision is optional
Wall Materials: Graphite, high purity, r =1.80 g/cm3, A-150 tissue equivalent plastic
Signal Connector: BNC, mates with UG26OB/U or equivalent
Signal Output IC18: 2.7 x10E10 R/coul for air with Cs137
Leakage: Typically 5 x 10E-15 A when low noise coax is used (measured without collection voltage).
Collection Efficiency: 99% for 3x10E5 R/h @ 250V, 99% for 7x10E5 R/h @ 300V
Recommended Signal Cable: Low noise coaxial, e.g., MALCO 250-3834-0000
High Voltage Requirements: Positive or negative polarity, 250 to 500 V depending on source strength. Shell is at high voltage potential.
High Voltage Connector: MHV, mates with UG 932 A/U or equivalent; optionally SHV
High Voltage Cable: RG-59/U or equivalent
Overall Size and Weight: Length including connectors, 14.0 inches (35.7 cm); stem is 10.5 inches (26.7 cm) long; weight 94 grams
Calibration Furnished: R/coul at Cs137 with air and appropriate gas
Accessories: Supplied with wooden storage box


Ordering Information

See model numbers in table above. Add additional options below. All ionization chambers are supplied with storage box.
-GF: with gas flow provision
-WH: with waterproof housing
-BC: with TE buildup cap
Consult factory for other wall materials.

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Specifications subject to change without notice.
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