- Designed for ultra long-term stability error of
approximately 0.1% per five years.
- Virtually removes effects of system leakage during
measurement. Uncorrected leakage <10fA over temperature
- Maximum non-linearity variation from straight line of 0.1%
for all charge and current ranges.
- Automatic exposure reset.
- Wide bias voltage range from -500V to +500V.
- Eleven user-defined bias settings accurate to ±0.3 volt.
- Stores up to 32 user-entered ion chamber calibration
- Displays leakage and accumulated charge.
- Displays average current and dose rate.
- Battery and line operation.
- Flexible data presentation with up to 16 user-defined
- Meets all specifications within five minutes after power-on.
The Advanced Therapy Dosimeter, Model 35040, is a reference
grade instrument with superior performance in either its basic
configuration or customized to user preferences. The Advanced
Therapy Dosimeter exceeds the recommendations of calibration
laboratories for leakage, linearity, and stability by a wide
margin. The long-term stability error is designed to be less than
0.1% over five years. Non-linearity error is much less than
recommended by calibration laboratories, and system current offset
error is virtually nonexistent for practical measurements. The
Advanced Therapy Dosimeter satisfies fundamental user requirements
and provides the flexibility to customize displays and perform
automatic calculations. While significantly raising the standard
of measurement, the Advanced Therapy Dosimeter provides useful
information that is not available from other dosimeters.
The Advanced Therapy Dosimeter is used in calibration dosimetry,
quality assurance, and diagnostic testing of linear accelerators.
A unique electrometer design provides more accurate dose and dose
rate measurements than conventional high meg resistor or capacitor
feedback electrometers. The flexibility of the Advanced Therapy
Dosimeter optimizes user efficiency and saves time. The Advanced
Therapy Dosimeter is fully stable within five minutes, a fraction
of the time of conventional dosimeters. Front panel controls
select ion chamber calibration factors, enable air density
correction, facilitate temperature and pressure entry, and allow
bias voltage selection and display. The Advanced Therapy Dosimeter
measures effective exposure time in a single exposure, thus
eliminating the need for multiple exposures for Cobalt 60 and
User-customized and front-panel selectable display screens can
simultaneously and in real time show dose, dose rate, effective
exposure time, average current/rate, accumulated charge/dose, bias
voltage, leakage, and other important information that ensures the
validity of the measurement.
The Advanced Therapy Dosimeter's customization software allows
the user to design up to 16 display screens that display internal
conditions, set-up parameters, measurement values, and text
information. The software allows the user to enter up to 32 ion
chamber calibration factors. Users can program up to 11 bias
voltages in 1/10-volt increments from -500 volts to +500 volts in
any sequence and select the values from the front panel. The
customization software operates with an IBM-compatible PC and
connects via a RS-232 cable.