Loading PHI specimen mounts
This post explains the mechanics involved with loading PHI specimen mounts used on most of the older to current Physical Electronics surface analysis systems.
There are a number of different sizes and shapes of specimen (sample) mounts and they all use the same basic mounting and docking scheme.
The most common sample mount used on older Physical Electronics XPS and AES surface analysis systems is the Model 190 flat one inch diameter specimen holder shown below.
The basic concept is that there are two grooves on the outside of the sample mounts which are used to transfer the sample mount into the vacuum chamber, and to dock the sample mount to the specimen stage. The transfer arm has a fork on the end which connects to the bottom groove on the specimen mount and the specimen stage has three clips which snap into the bottom groove and hold the specimen mount to the stage. The top groove is used to hold the specimen mount while mounting it to the transfer arm fork or in the case of scanning auger systems, to transfer to the parking attachment.
There are two essential steps required to successfully dock and removing the specimen holders;
- Make sure that the specimen stage is perfectly centered under the transfer arm fork.
- The specimen stage center clip needs to be lined up with the notch on the transfer arm fork.
Once you have the location of the specimen stage micrometers for the load and un-load positions you can make some marks on the specimen stage micrometers so that you will be able to easily re-position the specimen stage for loading and unloading.
Loading PHI sample mounts procedure:
- After you attach the sample that you want to analyze to the specimen holder (using screws and clips or carbon/silver tape). Back-fill the intro with dry nitrogen and mount the specimen holder to the sample fork. There are 2 different types of specimen mount holding tools as shown below. Or you can use a clean needle nose pliers. Pull the transfer arm out a little bit so that you can lower the specimen mount into the load lock and then move the transfer arm back in so that the fork slides over the bottom groove on the specimen mount.
- Pump down the load lock by pressing the Pump Intro button on the AVC remote box.
- Move the specimen stage micrometers to the load sample position. The X and Y axis will be centered under the intro fork but the Z axis will be lowered from the dock position by at least 1 cm.
- After the load lock has pumped down (5 bars on the AVC remote plus a few more minutes – the longer you pump the sample, the lower the pressure burst and the less out-gassing you will have) press the Intro Sample button on the AVC remote and the V1 gate valve will open.
- Move the intro arm forward to bring the sample into the vacuum chamber and push it all the way in until it hits the stop. If adjusted properly, the stop will be the correct position for docking the specimen mount.
- The specimen mount should be directly above the specimen stage clips. If not adjust the X and Y on the specimen stage as needed.
- Raise the specimen stage Z axis so that the clips slide into the specimen holder bottom groove. You may need to slightly adjust the X Y or rotation (if so equipped) so that the specimen holder snaps into the clips. Slightly moving the specimen stage rotation or the tilt on the transfer arm can also help the specimen mount to snap down into the clips on the specimen stage as you move the specimen stage Z axis. If the specimen mount does not snap down with a minimal amount of force, back off and recheck the specimen stage X and Y position. You do not want to damage any of the three clips on the specimen stage by crushing them. Once the clips have snapped in adjust the Z slightly until there is no gap between the bottom of the specimen holder and the specimen stage.
- After the specimen mount is docked to the specimen stage, slowly retract the intro fork until it separates from the specimen holder and then once clear, pull the intro arm all the way out of the chamber. The V1 gate valve will close automatically.
To remove a sample from the system, repeat the above procedure with the exception that the Z axis should be in the dock position so that the intro arm fork mounts to the lower groove of the specimen mount. Once you dock the load lock fork to the specimen mount, drop the Z axis on the specimen stage in order to separate the specimen holder from the specimen stage clips.
When the specimen holder is clear of the specimen stage you can pull the intro arm all the way out of the chamber and V1 will close automatically.
RBD Instruments provides new and used PHI specimen mounts. We also provide the sample clip assembly. Contact us for more information at 541 330 0723 or visit our website by clicking the image below.