A blog on the repair, operation and calibration of surface analysis systems and components including electron spectrometers, sputter ion guns and vacuum related hardware. Click on the Index tab below to see a list of all posts. Visit our website at http://www.rbdinstruments.com
Actuel 1.8 adds new features to assist with saving and graphing data. As always, updates are free and can be found here.
Set the Auto-Save Interval
Prior to Actuel 1.8, the auto-save interval for recorded graph data was every 5 minutes. The latest version gives you the option to save the data every half-minute to every 30 minutes.
Option to Show / Hide Graph
You now have the option to show or hide the graph display. This is useful if you only want to record data and not view the real-time graph information. Large data sets and fast sampling rates can cause some performance issues on slower PCs, and this option mitigates that.
Set a Fixed Range for the Graph Y-axis
By default, the Y-axis scale automatically adjusts to the range of the incoming data, with the options to display dual or single polarity, and to zero the baseline.
9103 Actuel Y-axis Default Range
The fixed-range option for the Y-axis is especially useful, as it serves as a Y-axis zoom (independent of the X-axis) and also allows you to more easily compare data between multiple units or sessions. You can set the min and max for the range as well as the units.
9103 Actuel Y-axis Default Range
There have been some minor changes to the user interface to accommodate the new options. The Data window is now (slightly) larger, and the formatting options have been moved to the Data Options group.
For more information on RBD Instruments’ 9103 USB picoammeter, visit our website here –
The raster size potentiometers that are used in the 11-065 ion gun control are coarse single turn potentiometers that make it difficult to accurately reproduce raster sizes.
By replacing the single turn potentiometers with 10-turn 1% potentiometers, the accuracy of the raster sizes is greatly improved. This will improve the repeatability of your sputter rates when changing raster sizes. One turn of the raster size potentiometer will now equal 1 mm instead of 10 mm.
When you replace the 25 kΩ 1-turn deflection potentiometers in the 11-065 with 25 kΩ 10-turn potentiometers, note that CCW = black and CW = solid brown. The other wires are the wipers.
You will also need to replace the one turn raster size knobs with a 10 turn vernier dial.
TIP: When removing the old potentiometers you can simply cut the tabs off the old ones and then insert and solder the tabs into the new potentiometer. That is much easier than un-soldering the wires from the old potentiometers.
It is very important that the CW, CCW and wipers wires match up with the old potentiometers. Otherwise the raster sizes might be backwards (0 = full raster and 10 = zero raster.
If your 11-065 controller ever needs repair and you send it to RBD Instruments, we will ask you if you would like us to add this update to your 11-065 as part of the repair.
If you are new to UHV vacuum chambers and how to create a seal using copper gaskets when mounting optics, this blog post has some useful tips.
In many cases, installing the copper gaskets that are used to seal flanges on UHV vacuum chambers is as simple as placing the copper gasket in the knife edge recess. If the flange is facing down, then the gasket can be placed on the optics part being installed and the gasket will stay in place.
But in cases where the flange is perpendicular to the floor, the gasket will not stay in place on its own because the gravitational constant will prevent the gasket from staying in place. In other words, the gasket will fall.
There are a few ways to install a gasket onto the flange. But first, you need to make sure you’ve removed the old gasket properly.
Removing Gaskets
When you remove the old gaskets, you want to be very careful not to nick the knife edge on the flange when removing the old copper gasket because a nicked knife edge often results in a vacuum leak. And, nicked knife edges are difficult and sometimes very expensive to repair.
Usually the gaskets will come off easily with a minimum amount of force. For those gaskets that are pressed in tightly and very hard to remove, I have found that using a long-nosed vice grips locking pliers works quite well.
You can adjust the gap on the pliers so that it firmly clamps down on the gasket, then simply bend the pliers so that the leverage will pop the gasket off the flange. It works every time and most importantly, it follows the number one rule of flanges – protect the knife edge. You can use a screwdriver to pry up the edge of the gasket, but if the screwdriver slips, you risk damaging the knife edge.
The first method is to use a gasket clip. Gasket clips hold the copper gasket to the flange via a spring action. They line up with the flange’s leak check groove and hold the gasket in an area that is just past the knife edge of the flange.
Here is a link to the gasket clips that Ideal Vac provides:
Gasket clips work well most of the time. Sometimes they will not work due to geometry limitations with other nearby flanges or optics.
If you do not have gasket clips, there are some other ways to mount a copper gasket to a horizontal flange.
Method 2: Elongate the Gasket
The second method is to elongate the gasket. This works well for larger copper gaskets, such as those for 10-inch and 8-inch flanges. It works with smaller gaskets as well, but you will need to drop them from a higher distance from the floor.
For an 8-inch gasket, hold the gasket about 1 foot above the floor. Hard concrete floors work best. This technique will not work on carpet.
Drop the gasket on its edge and it will hit the floor and bounce back up. You need to catch it when it bounces back up. If you don’t catch it and it falls to the floor, that is OK. You will just need to clean the gasket off with some isopropanol or methanol.
It takes a little bit of practice to get the correct height from which you are dropping the gasket. But the general rule is that the smaller the gasket, the higher the height. I have used this technique on 10-inch to 4.5-inch gaskets with good results. 10-inch flange gaskets should be dropped from about 6 inches. 4.5-inch gaskets should be dropped from about 18 inches. 2.75-inch gaskets are more difficult as they are harder to deform than the larger gaskets.
When you insert the gasket into the flange, you need to press it into the knife edge recess. The slight elongation will act like a spring and the gasket will stay in place.
Method 3: Cellophane (Scotch) Tape
Which brings us to the third method for mounting copper gaskets – cellophane (Scotch) tape.
You can use Scotch tape to mount the gasket as long as the tape is just barely on the gasket. Since the tape is mounted outside the knife edge, then it is OK if any of the tape stays on the gasket because it will be on the air side of the knife edge.
The pictures below show the knife edge cuts on common gasket sizes. For most copper gaskets (2.75- to 10-inch flange sizes) the knife edge is approximately .100 inches from the outside edge of the gasket. For the very small 1.33” flange, it is .050 inches from the gasket’s outside edge.
The procedure is to place the tape to where it is barely on the gasket (outside the knife edge region) and then very lightly touch the flange. You can use 2 or 3 sections of tape as needed.
Once you get the optics part mounted to the flange with just a few nuts or bolts to hold it in place, pull the tape straight up and away from the flange. Usually all of the tape will come out. But if any small piece of tape is left behind, it will not matter since it is on the air side of the knife edge and will not have an effect on the vacuum.
Rotate the flange slightly to make sure that the copper gasket is properly seated before you tighten the bolts.
And don’t forget that if you are up to air for awhile and need to cover a flange or optics component with aluminum foil, you should use a UHV foil such as All Foils. UHV foil does not have an oil coating on it like foil from the super market does.
There are 2 schools of thought on tightening copper CF gaskets. The most prevalent is to use a star pattern where you crisscross the bolts that you are tightening as shown in the drawing below.
Star pattern method of tightening bolts on a CF flange
The other method is to simply tighten in a circle pattern (which is the method that I prefer). The trick with this method is that you need to use very small increments of increased torgue as you move from one bolt to the next, otherwise you can over-tighten one section of the gasket or possibly bend the flange out of shape which would result in a leak. But, going in a circle is easier to keep track of which bolt is next.
Here are some links to other posts on the subject of how to tighten a CF copper gasket, so that you can make your own decision on which way is best. The top link has some information on recommended torgue for different size flanges.
