APPLICATIONS

The THEBES™ II is used to perform linear accelerator quality assurance using

physicist-preferred air ion chamber technology for dose measurement, avoiding

the ion transport issue of the competing liquid chamber technology and radiation

damage issues of diode detectors. The detector array consists of 47 waterproof

sealed air ion chambers in a linear array. Two detector arrays will be offered:

Model 7020 with 47 ion chambers on a 0.5 cm pitch (23.5 cm total active length)

and Model 7040 with 47 ion chambers on a 1 cm pitch (47 cm total active length).

The software will perform beam contour analysis such as flatness and symmetry.

Beam contour data will be saved in an Access compatible database, facilitating

daily, weekly, yearly checks, aiding in following the guidelines in TG-40 and TG-51.

• 47 air ion chambers

• 0.5 cm spacing

• Central axis chamber

• Waterproof and sealed or vented

• Simultaneously checks symmetry,flatness, light field vs. radiation ield coincidence,

field size, beam enter, penumbra, constancy, and ntegrated total dose

• Real-time dose maps for service and setup

• No electronics in or near the beam

• Windows® applications software

• Calibrated by Global Calibration Laboratory (GCL)

The Victoreen THEBES™ II consists of a linear ion chamber array, electrometer,

communicator, THEBES™ II Contour Manager software, wall mount power supply,

and interconnecting cable. An acrylic base plate that holds the ion chamber array

and build up plates are also provided. The linear ion chamber array is permanently

connected to the electrometer by a 1.5 m shielded multiconductor cable to eliminate

radiation damage to the electrometer.

The THEBES™ II linear ion chamber array is a waterproof, linear array of 47 ion

chambers on 0.5 cm centers. The total active length of the array is 23.5 cm.

THEBES™ II has a 48 channel electrometer for 47 ion chambers plus diagnostics.

The THEBES™ II communicator provides power and the communication interface

for the THEBES™ II electrometer.

THEBES™ II Contour Manager Software is a Windows® based application that

will acquire beam contour data from the detector array and display graphically.