RaySafe Xi - Manual (Page 34)

dose
the dose is accumulated from the start trig point plus trig delay until the end trig.
Figure 2. Trig delay activated
NOTE! The trig level setting (25, 50 or 75 %) affects the dose measurement.
NOTE! The backscatter protection of the RaySafe Xi R/F detector may cause differences in readings
compared to ion chambers. If both are placed directly against an object, i.e. image receptor or
lead apron, the RaySafe Xi R/F detector will read lower compared to an ion chamber. However
the RaySafe Xi R/F detector will be reading True Input Dose while the ion chamber is reading
the input dose plus back scatter from the object directly behind it. If using the RaySafe Xi R/F
detector and an ion chamber in free air they should be comparable ± both meter tolerances.
the raysafe Xi r/f detector measures dose with a multi-segment sensor, and the active compensation feature
automatically corrects the displayed dose (and dose rate) for beam qualities with an hVL of 1 – 14 mm al (for
example: a filtration of 45 mm al at 140 kVp gives an hVL of about 13 mm al).
for mammography the active compensation corrects the dose for selected beam quality with an added
filtration of up to 2.5 mm al (not valid for the w/al scanning detector).
the raysafe Xi transparent detector measures dose with a multi-segment sensor, and the active compensation
feature automatically corrects the displayed dose and dose rate for beam qualities with an hVL of
2 – 10 mm al.
the Ct meter is an ionization chamber with carbon fiber housing. It has a flat energy dependence curve and
automatic pressure and temperature correction.
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raysafe Xi user Manual – Measurement definitions