Fluke 90100 manual Setting the Electrometer Gains and Offsets, Charge Gain QG

Model 90100

Operators Manual

The 35360A TRACKER Display supports four units of radiation. To convert between these units, use Table 5-1. This table was developed from accepted definitions of radiation units. While Table 5-1 shows sieverts and grays as equivalent, we acknowledge that other factors may contribute to this conversion. Additionally, the instrument allows you to display readings in monitor units. Because monitor units are not defined in terms of radiation units, and monitor units could vary from machine to machine, we suggest that you develop your own conversion factor from the Ion Chamber Calibration Units to monitor units.

Table 5-1. A Guideline to Converting Between Units

To Convert:	To:	Multiply By:
roentgen (R)	gray (Gy)	.00879
roentgen (R)	sievert (Sv)	.00879
roentgen (R)	rad	0.879
gray (Gy)	roentgen (R)	113.77
gray (Gy)	sievert (Sv)	1
gray (Gy)	rad	100
sievert (Sv)	roentgen (R)	113.77
sievert (Sv)	gray (Gy)	1
sievert (Sv)	rad	100
rad	roentgen (R)	1.1377
rad	gray (Gy)	.01
rad	sievert (Sv)	.01

DISPLAY CALIBRATION ITEMS

Charge Gain (QG)

The 35360A TRACKER Display uses the Charge Gain to convert the number from the analog-to-digital converter to charge. The Charge Gain must be in units of nanocoulombs per count.

Current Gain, Current Zero (IG and ADZ)

The 35360A TRACKER Display uses the Current Gain and Current Zero to convert the number from the analog-to-digital converter to current. The Current Gain must be in units of nanocoulombs per minute, and the Current Zero must be in units of counts.

Ion Chamber Calibration Factor (ICCF)

The 35360A TRACKER Display uses the Ion Chamber Calibration Factor to convert charge from the 35300A TRACKER Detector ion chambers to radiation units. The factory calibrates the 35300A TRACKER Detector in units of roentgens per nanocoulomb. The accuracy of the calibration factor is ± 2.5%.

5.7 Setting the Electrometer Gains and Offsets

To set the electrometer gains, you must have a Keithley Instruments, Inc. Model 263 Calibrator/Source or equivalent. The current required for calibration procedure below must be 15 nanoamperes ± 0.07%; the charge required for calibration procedure below must be 950 nanocoulombs ± 0.5%. The Electrometer Offsets must be specified before the Electrometer Gains.

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