- Dose acquisition and
simultaneous display from five detectors
- Measures dose or dose rate
- Constancy, flatness, and
symmetry in one measurement
- Absolute and percent-of-center
- 4-line by 20-character Vacuum
Fluorescent Display (VFD) for excellent readability in all
- Temperature and pressure
The TRACKER Therapy Beam Evaluation
System, Model 90100, is a quality assurance system that measures
therapy radiation sources, including dose and dose rate, enabling
user calculation of beam constancy, flatness, and symmetry. The
system consists of the Model 35300A Detector and Model 35360A
The Model 35300A TRACKER detector
array incorporates four orthogonally-placed ion chambers on a 10cm
radius from a fifth isocentrally-located ion chamber, allowing
ratio-to-center dose measurement. Each ion chamber, which is
identical to the others and vented to the atmosphere, is a
circular, parallel-plate configuration and is fully guarded for
low leakage. An overlay indicates ion chamber locations for
alignment with a therapy beam light field system. The Model 35360A
TRACKER display contains five electrometers and is characterized
by a microprocessor controlled, 4-line by 20-character Vacuum
Fluorescent Display (VFD) that enables excellent readability of
dose and dose rate measurements in virtually any lighting
The TRACKER Therapy Beam Evaluation
System performs quality assurance tests for linear accelerators,
Cobalt 60, and therapeutic x-ray equipment. The system's quick
setup and operational ease make it ideal for daily checks of beam
constancy, symmetry, and flatness.
A five-channel electrometer enables
measurement of dose or dose rate in either absolute or ratio to
center. Dose measurement values may be displayed in units of R,
rad, Sv, or Gy. Dose rate measurement values may be displayed in
units of R/min, rad/min, Sv/min, or Gy/min.
The TRACKER System may be operated
from either AC line power or from its high capacity internal
battery. The battery is charged automatically when the unit is
connected to AC line power, either during use or when idle.
Consulting physicists and service
engineers will appreciate the TRACKER System's portability. An
optional carrying case eases transport and storage. Other optional
accessoriesinclude buildup plates of various thickness' and
materials and a buildup retaining hardware kit.
- Measurement values from
peripheral ion chambers displayed in either absolute dose
measurement units or as percentage of center ion chamber's
4-line by 20-character VFD corrects for air density and
displays measurement results directly in user's choice of
- Precision five channel
electrometer provides +/-0.05% linearity.
- High performance rechargeable
system allows eight hours of continuous operation from a
three-hour charge; low battery annunciator indicates when
<30 minutes of operation remains.
- Levels of internal 300V
electronic bias supply and rechargeable battery supply are
continuously monitored; annunciators indicate abnormal bias or
low battery voltage.
Front Panel Features
- Power On/Off Key: All front
panel settings are stored at power-down and recalled at
- Test/Detector Key: Sequence of
screens display Firmware Revision, Last Calibration Date, Bias
Voltage Level, Battery Voltage Level, Battery Current, Ion
Chamber Calibration Factors, and optional text line.
- Units Select Key: Allows user
selection of dose or dose rate units (rad and rad/min).
Display Units Conversion Factor DUCF) as entered during
- Air Density Key: Allows user
selection of temperature and pressure, and displays Air
Density Correction Factor (ADCF). Also allows air density
correction to be switched on or off.
- Gain Select Key: Allows user to
switch Front Panel Gain Factors (FPGF) on and off. Displays
and provides a means of setting five individual gain factors.
- Measure Select Key: Displays
measurement screen and allows user selection of measurement
display mode for peripheral ion chambers (absolute or
percentage of center).
- Reset Key: Resets the displayed
dose measurement values.
- 4-Line by 20-Character Vacuum
Fluorescent Display (VFD): Provides excellent visibility in
all lighting conditions. Measurement values updated at a rate
of three per second.
Rear Panel Features
- RS-232 Receptacle (RJ-45 Style):
User customization and field calibration via supplied MS-DOS
Customization Program. Fully remote and automated operation.
- AC Line Power Receptacle: AC
Line Input Range of 100 - 240 VAC without operator switching.
IEC 320/C13 style receptacle enables worldwide operation by
simply switching line cords.
- Nominal Dose and Rate Display
- Dose Full Scale Dose Sensitivity
Rate Full Scale Rate Sensitivity
- 3093 rad 0.1 rad 3093rad/min 0.1
Source Modes and Energies
Photons: 300keV to 25MeV, with
suitable buildup material.
Electrons: 2MeV to 25MeV, with suitable buildup material.
Recommended Operating Conditions
Source Distance: 100cm.
Collimated Field Size: 25cm x 25cm.
Source Dose Rate Range: 50 to 500 rads/min.
Nominal Chamber Characteristics
Window Area Density: 600mg/sq cm
(0.51cm acrylic plastic).
Sensitivity: 3.52 R/nC at 22oC and 760mm Hg.
Active Cross-Sectional Area: 0.93 sq cm.
Collection Efficiency: >99% at 500 rads/min pulsed; >99.9%
at 500 rads/min continuous.
Ion Chamber Factory Calibration
Method: Each of the five ion
chambers within the detector array is calibrated by comparison
with a reference standard ion chamber in a 60Co beam. The
comparison is performed in free air and results in a R/nC
Calibration Factor for each of the five ion chambers.
STANDARD SYSTEM COMPONENTS
- Display - 35360A
- Detector - 35300A.
- 49ft/15m Detector to Display
Interface Cable - 37783-15.
- AC Line Cord. (Both U.S. and
European styles available.)
- Instruction Manual - 37826.
Total Weight: 26lbs/11.7kg.