Fluke TRACKERTM 90100 - Manual (Page 9)

General Information
Specifications
1
1-5
1.6.2 Model 35360A TRACKER Display
Measurements Mode
The measurement mode is user-selected from the front panel prior to the start of the exposure.
Dose (rad): Electrometer is operated in integrating mode with capacitive feedback.
Dose Rate (rad/min): Electrometer is operated in non-integrating mode with resistive feedback.
Display Mode
The display mode is user-selected from the front panel and may be selected before, during, or following
the exposure.
Absolute: All five ion chamber measurement values are displayed in absolute dose measurement units
(typically rads or rad/min) as defined by the dose measurement unit's description.
Percent-of-Center: Only the center ion chamber measurement value is displayed in absolute dose
measurement units (typically rad or rad/min) as defined by the dose measurement unit's description.
Four peripheral ion chamber measurement values (top, bottom, left, and right) are displayed as a
percentage of the center ion chamber measurement value.
Electrometer / A-D Converter
Nominal Full Scale Output: 3 volts.
A/D Converter Resolution: 16 bits unipolar.
Nominal Full Scale and Sensitivity in Electrical Units:
A-D Dose
Full Scale
A-D Dose
Sensitivity
A-D Rate
Full Scale
A-D Rate
Sensitivity
1000.0 nC ± 2% 0.015 nC/count 1000.0 nC/min ± 2% 0.015 (nC/min)/count
An overrange indication will be displayed when the input current or charge have exceeded the full-scale
values. The full-scale value of any unit is guaranteed not to differ from nominal values by more than ±
2%.
Long Term Stability: Expected to be less than 0.25% of reading per year.
Non-linearity: Less than ± 0.4% of range.
Display Resolution: 0.003% of range (4-3/4 digits) for both dose and dose rate. Display resolution is
limited by the following relationship for all display units;
1 A-D Count ≤ 1 Display Count < 10 A-D Counts.
This relationship insures that the resolution of the measurement display values is as high as possible
without exceeding the inherent resolving capability of the
A-D converter.
Gain Temperature Stability: Less than ± 0.4% of reading over operating range of 10°C to 35°C.
Measurement Noise: Charge and Current measurement noise are less than ± 1 count at the display
exclusive of source noise effects. Typical effects from a Co60 source are on the order of ± 0.2 rad/min
at 100 rad/min. Source noise effects during dose rate measurements on a linear accelerator may be
excessive.
Measurement Accuracy: Fluke Biomedical factory calibration will provide a basic Charge (Current)
measurement accuracy of ±1% of reading ± 0.3 nC (± 0.3 nC /min) exclusive of long-term drift and
temperature effects. Similar results may be obtained in the field using a suitable calibration source
such as the Keithley Instruments, Inc. Model 263 Calibrator/Source and the included Customization
software.
Current Leakage: Less than 1 pA (typically 1 rad in 5 minutes)
Zero Offset Voltage: Factory trimmed to 0 counts at the display.