QSA Global, Inc.
40 North Avenue Burlington, MA 01803
888.272.2242
781.272.2000
qsa-global.com
Operations Manual
MAN-038 March 2019
Page 22 of 100
STEP 4 Continued
Projecting and Retracting the Source Assembly
Push the lock slide
GREEN MARKING
laterally from
left to right (as seen behind the projector) until the lock
slide
RED MARKING
fully appears from behind the
previous position of the lock slide and you feel or hear
the sleeve snap into the slide.
When the
GREEN MARKING
is visible, the source
assembly is locked into the secured position within the
gamma-ray source projector.
When both
RED MARKINGS
are visible, the
source
assembly is free to be projected from, and retracted
to, the gamma-ray source projector.
Ensure all personnel leave the immediate area.
Go to the remote control crank.
If an odometer is fitted, adjust the reset knob to read
zero.
The source assembly can now be projected.
Projecting
Rapidly rotate the control crank handle in the
EXPOSE
direction (counter-clockwise on standard
controls, clockwise on reverse controls) to move the source assembly out of the gamma-ray source
projector to the radiographic focal position.
The control crank handle will stop turning when the source reaches the source stop. Do not use
excessive force.
The odometer (if fitted) will indicate the approximate total distance traveled, 7 ft (2.1 m) for each guide
tube section.
Set the brake to ON to prevent movement of the source assembly during the radiographic exposure.
Start timing the radiographic exposure from the moment the source assembly reaches the exposure
head.
Survey meter readings observed during the projection operation should increase rapidly from
background to a high level as the source emerges from the projector. Then readings should fall as
the source moves out towards the focal point, fall sharply as the source enters a collimator (if used)
and remain steady throughout the exposure.
Actual survey meter readings will depend on the source activity, distance, collimators and shielding.
The sequence of changes should be observed and the readings noted.
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