CPI Indico 100 Series Service And Installation Manual page 171

CPI Canada Inc.
3D.8.0 RLF COMPENSATION (Cont)
Step
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
Millenia / Indico 100 Series Service Manual
Place 2.0 mm of copper (pure grade) in front of the collimator, ensuring that the radiation
is COMPLETELY blocked by the absorber.
Select the slowest film screen combination to compensate. This will normally be FILM
SCREEN 1.
Select >>.
Select RLF COMPENSATION.
From the LF COMP menu, select 50MSEC and set the value to 0 using the + or -
buttons.
Select mA appropriate to the film speed i.e. 100 mA for 100 speed film.
Make an exposure and adjust the mA if necessary to give an exposure time of
approximately 50 ms.
Load a test cassette with fresh film and install it in the image receptor.
Make an exposure using the same techniques. Record the mAs, then develop the film.
Note the O.D. This should be within 10% of the O.D. that was noted during AEC
calibration.
Make an exposure and reduce the mA to give an exposure time of approximately 500
ms.
Make an exposure using the same techniques. Record the mAs.
Enter an RLF offset at 50MSEC to give an mAs increase of approximately 10%.
Load a test cassette with fresh film and install it in the image receptor. Make an exposure
and develop the film.
If the measured O.D. is not within 5% of the value in step 10, adjust the 50 ms RLF offset
value as appropriate using the + and - buttons.
Repeat steps 14 and 15 until the required O.D. is achieved.
Make an exposure and reduce the mA to give an exposure time of approximately 1000
ms.
Select the 500MSEC RLF adjustment and set the value to 0 using the + or - buttons.
Make an exposure using the same techniques. Record the mAs.
Enter an RLF offset at 500MSEC to give an mAs increase of approximately 20%.
Load the test cassette with fresh film and install it in the image receptor. Make an
exposure and develop the film.
If the measured O.D. is not within 5% of the value in step 10, adjust the 500 ms RLF
offset value as appropriate using the + and - buttons.
Repeat steps 21 and 22 until the desired density is achieved.
THE FOLLOWING STEPS ONLY APPLY IF TECHNIQUES ARE USED RESULTING IN
AEC EXPOSURE TIMES GREATER THAN APPROXIMATELY 1500 MS.
Make an exposure and reduce the mA such as to give an exposure time of
approximately 1500ms.
Select the 1000MSEC RLF adjustment and set the value to 0 using the + or - buttons.
Make an exposure using the same techniques. Record the mAs.
Enter an RLF offset at 1000MSEC to give an mAs increase of approximately 30%.
Load the test cassette with fresh film and install it in the image receptor. Make an
exposure and develop the film.
If the measured O.D. is not within 5% of the value in step 10, adjust the 1000 ms RLF
offset value as appropriate using the + and - buttons.
Repeat steps 28 and 29 until the desired density is achieved.
Select BACK three times to return to the AEC CALIBRATION menu.
Repeat steps 2 to 31 for FILM SCREEN 2 and FILM SCREEN 3 if required.
Action
Ch # 740904-06 Rev. D
3D
AEC Calibration
Page 3D-37