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 • Measurement values from peripheral ion chambers displayed in
either absolute dose measurement units or as percentage of
center ion chamber’s measurement value
• Microprocessor-controlled, 4-line by 20-character VFD displays
measurement results directly in user’s choice of radiological
units corrected for air density
• Precision five channel electrometer provides ± 0.03% 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 300 V electronic bias supply and rechargeable
battery supply are continuously monitored
• Annunciators indicate abnormal bias or low battery voltage
The TRACKER™ Therapy Beam Evaluation System, Model 90100, is a quality assurance system that measures high energy accelerators and Co60 dose and dose rate, enabling user calculation of beam constancy, flatness, and symmetry. The system consists of the Model 35300A detector and Model 35360A display. The Model 35300A TRACKER detector array incorporates four orthogonally placed ion chambers on a 10 cm 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. The entrance surface indicates ion chamber locations for alignment with a therapy beam light field system. The Model 35360A TRACKER™ display contains five electrometers and a microprocessor-controlled, 4-line by 20-character, vacuum fluorescent display (VFD) that provides excellent readability of dose and dose rate measurements in virtually any lighting condition.
The TRACKER™ Therapy Beam Evaluation System performs quality assurance tests for linear accelerators and 60Co. 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 accessories include buildup plates and a buildup retaining hardware kit.
• Therapy Beam Evaluation System
• Superior stability verified by years of customer satisfaction
• Simultaneously measures dose or dose rate from five detectors
• Absolute and percent-of-center display modes
• Corrections for temperature and pressure
• 4-line by 20-character VFD for excellent readability in all lighting
conditions
• User selectable gain factors
Specifications
Electrometer
Accuracy 1% of reading (1 count)
Stability <0.25 % of reading per year
Zero drift (1 count 10 °C to 35 °C)
Nominal ion chamber characteristics
Window area density 600 mg/sq cm (0.5 cm acrylic plastic)
Sensitivity 3.52 R/nC at 22 °C and 760 mmHg
Active cross-sectional area 1.06 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 Co60 beam. The comparison is performed in free air and results in a R/nC calibration factor for each of the five ion chambers.
Source modes and energies
Photons 300 keV to 25 MeV, with suitable buildup material
Electrons 2 MeV to 25 MeV, with suitable buildup material
Recommended operation conditions
Source distance 100 cm
Collimated field size 25 cm x 25 cm
Source dose rate range 50 rads/min to 500 rads/min
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 V ac to 240 V ac without operator switching. IEC 320/C13 style receptacle enables worldwide operation by simply switching line cords
Physical
Detector dimensions 13.25" W x 17.25" D x 0.875" H
Display dimensions 10" W x 4" D x 9.4" H
Total weight 26 pounds
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