How to Change a Deuterium (D2) Lamp

Answer

This Information Applies To: All Agilent Spectroscopy Systems (AA50,55,240,280)

Issue:  The deuterium (D2) lamp will need replacing if the lamp fails to light or it cannot match the hollow cathode element lamp energy in the Optimize page in SpectrAA Software. See Figure 1.

Figure 1. Optimize page in SpectrAA Software

Steps to Follow:

Warning: Hot Surface and Eye Hazard. The deuterium lamp and its cover become very hot during operation. To prevent skin burns, allow the assembly to cool down before removing it.

Warning: The deuterium lamp emits dangerous levels of UV radiation. To avoid eye and skin damage, NEVER interfere with the interlock switch, or attempt to operate the lamp unless it is mounted in the instrument.

Figure 2. Video showing D2 lamp replacement

To change the deuterium lamp, follow these steps. For a video of lamp replacement, see Figure 2.

1. Make sure that the instrument is turned off. Allow time for the deuterium lamp and housing to cool.
2. If fitted, remove the hollow cathode lamp in Position 1.
3. Undo the thumbscrew at the top of the deuterium lamp compartment.
4. Lift the lamp assembly up and out of the lamp compartment.
5. Pull the white plug at the end of the deuterium lamp lead out of its socket, then completely remove the deuterium lamp assembly from the instrument.
6. Loosen the screw in the lamp holder assembly (labeled '1' in Figure 3) and slide out the lamp.

 Figure 3. D2 Lamp with bracket

7. Slide a new deuterium lamp through the clamp until the center of the aperture (labeled '2') is aligned with the notch in the backing plate (labeled '3'). This will set the correct height of the lamp.
8. Rotate the lamp so that the face of the lamp with the aperture (labeled '2') is parallel with the top edge of the bracket (labeled '4'). This will set the correct rotation of the lamp.
9. Tighten the screw loosened in Step 6 to secure the lamp in the holder.
10. Reconnect the deuterium lamp plug in the lamp compartment.
11. Replace the lamp in the lamp compartment and replace the thumbscrew at the top of the deuterium lamp compartment.

Tip: After installation, a new deuterium lamp must be aligned. See steps below.

To align a deuterium lamp:

1. Open a worksheet in SpectrAA Software for the appropriate element and has background correction turned on in the worksheet.
2. Go to Optimize page. See Figure 1. 
3. Confirm the hollow cathode (element) lamp is optimized by adjusting the two screws on the lamp holder for maximum signal on the HC Lamp scale. Adjust one screw, then the other, in both directions. See Figure 3. Click Rescale to bring the signal into range or increase a small signal.
4. Repeat the procedure in step 3, but observe the D2 lamp scale.
5. If the deuterium lamp signal is too small, check that you have correctly installed the deuterium lamp. If so, click Rescale. This will bring the signal back into range for display. You should also click 'Rescale' if the signal becomes too large.

Tip: If both lamps are correctly aligned, the 2 scales (HC and D2) on Figure 1, will be approximately the same height.

Learn how to effectively maintain and troubleshoot your Agilent Spectroscopy System): Guidelines for Troubleshooting and Maintenance of AA Systems