Cylindrical Ion Chambers - Victoreen Model 550 Series

Radiation Therapy

Cylindrical Ion Chambers

Victoreen Model 550 Series

• Cylindrical Ion Chambers for use

with Model 35040 and Model 530

electrometers

Introduction

Model 550 Series Cylindrical Ionization

Chambers are fully guarded thimble-type

probes for use in a variety of applications.

Equilibrium caps are available for each

probe, extending their energy range up to

12 MeV. Sensitive volumes have been

selected such that the nominal coulomb-

to-roentgen calibration factors are

convenient powers of ten. The cables may

be terminated by triax BNC connectors for

compatibility with Model 530, Model

35040 electrometers, or coax UHF

connectors for compatibility with the older

model electrometers.

Applications

The family of Cylindrical Ionization

Chambers is designed to meet a wide range

of radiation measurement and dosimetry

applications required for diagnostic x-ray

and radiation therapy in medical facilities.

The 550 Series Ion Chambers offers volumes of 330, 33, 3.3, 0.33 cm 3 for scatter, dose

and rate measurements and accommodate energies from 21 keV to 12 MeV when used

with equilibrium caps.

The selection guide on the next page will assist the user in selecting the appropriate

chamber for rates from 0.03 to 2300 R/s and for sensitivities from 100 to 0.1 nA/R/s.

• Wide range of applications in

Diagnostic X-Ray and Radiation

Oncology suites

• Accommodates energies from

21 keV to 12 MeV (with

equilibrium cap)

• The 550 Series offers volumes of

330, 33, 3.3, and 0.33 cm 3

• Chamber sensitivities are

available for 100, 10, 1, and

0.1 nA/R/s

• These chambers accommodate

rates of 0.03, 1.5, 10, or 2300 R/s

• Ion Collection Efficiency

information is available for specific

frequencies

Specifications

Available model(s)

Equilibrium caps - model numbers and

specific energies

550-3 550-4 550-5 550-6A

550-3

550-4

550-5

550-6A

Scatter, Diagnostic

Orthovoltage, Supervoltage

Teletherapy, Orthovoltage

Supervoltage, Diagnostic

Applications

137 Cs, 60 Co,

2 MeV 550-3-26 550-4-26 550-5-26 550-6-25

4 MeV 550-3-27 550-4-27 550-5-27 550-5-26*

6 MeV 550-3-28 550-4-28 550-5-28 550-5-27*

8 MeV 550-3-29 550-4-29 550-5-29 550-5-28*

10 MeV 550-3-30 550-4-30 550-5-30 550-5-29*

12 MeV 550-3-31 550-4-31 550-5-31 550-5-30*

* Used in conjunction with 550-6-25.

Volume

330 cm 3

33 cm 3

3.3 cm 3

0.33 cm 3

± 6%, 21 keV to 520 keV

without build-up medium

± 3%, 42 keV to 520 keV

without build-up medium

Energy Response

Sensitivity

100 nA/R/s

10 nA/R/s

1 nA/R/s

0.1 nA/R/s

**Intensity Limit @ 99.5% (Rate)

0.03 R/s

1.5 R/s

10 R/s

2300 R/s

Ion Collection Eff. (Pulse)

0.3 mR @ 60Hz

2 mR @ 400 Hz

6 mR @ 1.3 kHz

80 mR @ 17kHz

Wall Material

Acrylic

Polystyrene

Wall Thickness (density thickness)

166 mg/cm 2

133 mg/cm 2

Chamber Diameter

55.9 mm

28.2 mm

15.5 mm

7 mm

Cable Length

3 m

7.5 m

Max. Rep. Rate

60 Hz

400 Hz

1.25 kHz

17 kHz

*Stem Scatter-X-Ray

0.10%

0.70%

0.90%

0.70%

*Stem Scatter - 137 Cs

0.10%

0.20%

Distance for 1.5% Geometry Error

36 cm

18 cm

6 cm

Leakage

4 x 10 -15 A

Cable Termination: Triax BNC or Coax UHF. Specify when ordering.

* Stem Scatter is included in calibration.

** Rates are calculated from chamber geometry. For measurements of rates equal to or greater than those in the

above table, the chamber ion collection efficiency should be investigated.