Author Archives: Randy

Using the CMapp Extended Conditioning Feature for the microCMA

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CMapp (software for the microCMA) versions 1.2 and greater now have a feature which allows for extended conditioning of the integrated 3kV electron gun.

To access this feature, first make sure that the Beam Voltage and Filament Current in the Electron Gun Controller are both turned off.

Open the conditioning dialog box by selecting the System / Conditioning… menu command or by pressing the Conditioning Icon on the task bar. Next, follow these steps:

Conditioning Icon
CMapp Conditioning Dialog
CMapp Conditioning Dialog
  1. Check the Filament Degas box and set the time in minutes that you want the filament current to ramp up. For new installations the degas filament current value is imported from the factory properties file and can be set for a time of 60 minutes. After the electron gun has been fully conditioned you can reduce the Filament Degas Time to as short as 5 minutes.

  2. Next check the Beam Conditioning box and set the starting voltage to 0 and the ending voltage to 3000. For new installations this can be set to 120 or 180 minutes. That is how long it will take to bring the beam voltage all the way up. After the electron gun has been fully conditioned you can reduce the Beam Conditioning Time to as short as 5 minutes, but 20 or 30 minutes is the recommended minimum Beam Conditioning Time.

  3. Next check the Filament On box. Checking this will keep the filament on while the beam voltage is being ramped up. This helps to condition the electron gun by letting the heat from the filament keep the electron gun warm.

  4. Make sure that the Multiplier Conditioning box is not checked and then check the Extended Conditioning box. If the Multiplier Condition box is checked then the Extended Conditioning box is grayed out.

  5. With the Extended Conditioning box checked, enter the amount of time that you would like to let the electron gun sit with the filament current on and the beam voltage at 3kV.  Typically, this time is set to 120 to 180 minutes.

  6. Press the Start button and the Conditioning routine will ramp up the filament, then ramp up the beam voltage, then hold the beam voltage at 3000V and keep the filament ON until the time runs down.

The Extended Conditioning feature helps to outgas the electron gun and condition the electron gun ceramics which in turn helps with the stability of the electron beam and data signal to noise.

Learn more about Auger Electron Spectroscopy and RBD’s microCMA.

Scientific Glassblowing Resources

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Glassblowing has been around for thousands of years, and we see examples of it every day. From neon signs to Murano glass to Chihuly glass exhibits. Less well known but very important to science is the art and craft of scientific glassblowing which is the process of creating glass apparatus used in research and production.

Over the years I have had the good luck to be working at universities on one or another type of vacuum chamber related instrument where some glass to metal seal was damaged but was able to be repaired by the resident glass blower.  More recently it seems that many of the glassblowers at universities are retiring and not being replaced. So, to an extent, scientific glass blowing is becoming a nearly lost art as this interesting article on the History of Glassblowing explains.

But all is not lost as there are still scientific glass blowers who are handing down their glassblowing expertise to those who will carry on the tradition.

Also, there are some schools which offer glassblowing courses such as Salem Community College.

Listed below are some companies that provide custom scientific glass blowing services. These companies can also repair broken glass to metal seals.

Nunn Better Glass

http://www.nunnbetterglass.com/

Precision Glass Blowing

https://www.allenglass.com/

https://farlowsci.com/

Finally, The American Glassblowers Society has a Find a Glassblower link that lists glass blowers from different parts of the USA. https://asgs-glass.org/#

11-065 Filament Current Test

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This blog post shows you how to test the filament current supply on an 11-065 when it is connected to the 04-303 ion source.

Make sure that the 11-065 main power switch is OFF and then remove all cables and the power cord. Put the 11-065 on the table top or bench. Note that you will need to connect the black high voltage cable from J9 on the back of the 11-065 to the 04-303 ion source.

Remove the top cover on the 11-065.

11-065 Top Cover

Remove the High Voltage cover on the right hand side. Remove the 4 outside screws, not the 4 inside screws.

11-065 high voltage cover
Remove 4 outside screws

The two high voltage boards are now visible.

HV2 board is on the left, HV1 board is on the right

On the right hand HV1 board, E93 is the high voltage output, E92 and E91 are the filament current output connectors. With the 11-065 power OFF and the high voltage OFF and set to zero, unplug the E92 connector and then connect a current meter that can go up to 10 amps DC between the E92 cable lug and the E92 connector on the HV1 board. Make sure that the meter leads are not touching anything.

CAUTION! High voltages can be present on this board. As long as you have the high voltage on the 11-065 set to zero (fully CCW) and the high voltage switch set to off, then there is no high voltage present. Refer this test to someone who is trained to work safety with high voltage if you are not familiar with operating a DVM.

Remove E92 cable from HV1 board.
Fluke meter set to 10 amps DC

Make sure that the beam voltage switch is set to zero and the beam voltage control potentiometer is turned fully CCW.

Beam voltage set to OFF and control potentiometer set to zero (fully CCW)

Connect the black high voltage cable between the 11-065 and the 04-303 ion source. Connect the main power cable to the back of the 11-065.

Make sure that the Emission adjust potentiometer is fully CCW and that the emission scale switch is in the X1 position,and then turn on the 11-065 main power. The emission current should be zero.

When the 11-065 is turned on the emission current should be zero.

Slowly turn up the emission current (turn CW) until you get 25 mA of emission current.

Emission current set to 25mA with the emission scale set to X 1.

The DC current meter should read approximately 2.7 amps DC current at 25 mA of emission current on the 11-065 emission meter.

2.7 amps DC current with the emission current set to 25mA

If your emission current shoots up to 50mA when the 11-065 is first turned on or when the emission current is turned up then there is a problem with the 11-065 filament current circuit or the emission feedback circuit.

If you do not get any filament current then there is a problem with the 11-065 filament circuit or the ionizer in the 11-065.

For help with repairing your 11-065 controller please contact RBD Instruments for assistance.