Ludlum Measurements 43-5, Manual

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M43-5 Alpha Scintillator
February 2021
page 2
1. Remove protective window frame.
2. Remove window with metallized
polyester assembly from scintillation
retainer face.
3. Remove aluminized metallized
polyester from window screen and
clean off old glue from screen.
4. Inspect silicone gasket and replace if
damaged.
5. Inspect scintillation retainer face for a
complete coating of ZnS. Re-coat, if
necessary.
6. Reglue two layers of 0.4 mg/cm
2
aluminized metallized polyester to
window screen, placing glue only on
the outer edge of the screen.
** CAUTION **:
The thin metallized polyester film is
very susceptible to puncture. Extreme
care should be exercised while gluing
the aluminum metallized polyester to
the
window screen and when
reinstalling window with metallized
polyetser assembly to the face of the
probe.
7. Reinstall window with meatllized
polyester to face of probe.
Malfunctions caused by the tube, such as a zero
count, intermittent or a very reduced count,
may occur. After thoroughly checking for a
light leak, replacement of the tube may be
necessary. After removing the tube from the
probe body, check the front of the tube face. A
tube that has become defective may show clear
through the face, instead of the dark amber
color.
3.2 Replacement of PMT
To replace the PMT, perform the following
steps: (See Drawing 77 x 23.)
NOTE: If the replacement is for an original
“based” tube (Part No. 01-5001), refer to
instructions included in the installation kit.
NOTE: When needed, use thermal strippers
to strip the white Teflon high-voltage signal
wire to prevent damaging the wire.
1. Unfasten connector end cap (removing
four screws).
2. Slowly remove connector end cap and
pull out as far as wires will allow.
3. Remove (desolder) ground and high-
voltage wires from connector end cap.
4. Remove sponges.
5. Remove photomultiplier tube assembly
(including circuit board).
6. Unplug ground and high-voltage wires
from tube circuit board.
7. Remove metallic shield.
8. Slide the metallic shield over the new
tube and tape to tube.
9. Plug in ground and high-voltage wires
to appropriate connectors.
10. Place tube assembly into handle.
11. Install sponges.
12. Reconnect (solder) the high-voltage
and ground wires to connector end cap.
13. Install connector end cap to complete
final assembly.