Ziehm Imaging, Inc.
Vision Installation Manual
MAN 06-0015, Rev. A
Page 21
M a i n t e n a n c e R e p o r t : E x p o s u r e Ti m e s
Fig. 9
Plotting the Half-Value Layer
This halving thickness is the half-value layer (HVL) of the useful x-ray beam. The
HVL must not be less than 3.0 mm at 110 kVp. If the HVL is lower that 3.0mm, deter-
mine the cause and take corrective action.
Exposure Times
Test
1. Connect an oscilloscope to test point F on the U54 board.
2. Place 3 mm of lead in the path of the x-ray beam, to block radiation to the image
intensifier.
3. Set the kV to 60 kV, and time to 0.4 seconds.
4. Press the hand switch to release radiation.
5. Read the exposure time on the oscilloscope (start from the beginning of a positive
wave to the end of the negative wave that follows), and write the exposure time
below.
6. Set the time to one second, make another exposure, and write the time below.
If the variation in exposure time is greater than 10%, determine the cause and take cor-
rective action.
Exposure Time
0.4 sec. ________ s
1 sec. ______________ ms
