Fluke 90100 manual Model 35360A Tracker Display, Measurements Mode, Display Mode

General Information

Specifications 1

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	A-D Dose	A-D Rate	A-D Rate
Full Scale	Sensitivity	Full Scale	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.

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