Putting Together a Compact UHV (Ultra-high Vacuum) Chamber for Spectroscopy

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Small, inexpensive UHV chambers have been the backbone of many commercial labs and universities for decades. The cost of larger, feature-rich systems has gone up dramatically in recent years, making compact, DIY chambers even more cost-effective for specialized applications and education.

RBD has a range of products available to add value to your compact chamber, and in fact built our own recently to develop and test our microCMA compact Auger analyzer.

RBD Kimball Chamber
Kimball Physics chamber with RBD miniZ, IG2, and microCMA compact Auger analyzer

The Chamber

We started with an 8 inch spherical octagon chamber from Kimball Physics. This chamber has two 8.00″ CF and eight 2.75″ CF mounts, with an internal volume of  106.6 cu. in. (1,747 cc):

Kimball Physics Chamber
Kimball Physics 8.0″ Spherical Octagon – Vacuum Chamber

The vacuum chamber was fitted with an ion pump from Gamma Vacuum, and valves and windows from MDC. Affordable turbo pumps can be sourced from Pfeiffer (HiCube 80 Eco) and Edwards (nEXT85).

Rough vacuum gauges are available from a number of companies including Digivac.

Rough Vacuum Gauge
Rough vacuum gauge

Ion gauges and ion gauge controllers are available from a number of companies including Stanford Research Systems

Ion Gauge Controller
Ion gauge controller

Accessories

To assist with water vapor desorption, the chamber is fitted with RBD’s miniZ. The mini-Z uses UVC radiation to desorb water from the chamber walls, resulting in faster pump-down times and lower ultimate vacuum.

RBD miniZ
RBD miniZ water vapor desorption system

This chamber is also fitted with RBD’s IG2 2 kV low cost sputter ion gun for specimen cleaning:

Instrumentation

The ultimate purpose of this system was to house RBD’s microCMA compact Auger analyzer (shown below with the Z translator attached):

RBD microCMA
RBD’s microCMA compact Auger Analyzer

For applications that require elemental analysis, this chamber, with the addition of a PC and CMapp AES acquisition and data massage software, is now a complete system providing quantitative, surface-sensitive Auger electron spectroscopy. At around $50,000 for all the components listed here, this is one example of a budget-sensitive spectroscopy system that can be assembled, repaired and upgraded without costly field service visits.

50-096 X-ray source control DLL using Windows 10

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50-096 X-ray source DLL installation and setup for Windows 10

Overview

The 50-096 X-ray source control uses a RS232 serial port to communicate with the PC.    AugerScan talks to a Phi 50-096 DLL that in turn communicates with the 50-096.    This DLL was originally written for old 32 bit XP PCs and there are some tricks involved with getting it to install and operate correctly on a Windows 10 machine.

Note that the RS232 cable needs to be a straight rough type. Most newer PCs do not have a RS232 port so you will need to get a USB to RS232 adaptor.

The steps involved are as follows:

  1. Copy the 50-096 DLL to the windows/SysWOW64 folder
  2. Register the 50-096 DLL
  3. Set up the Com port

Step 1.  Copy the 50-096 DLL to the PC.    You can copy it anywhere on the PC, but initially copy it to the AugerScan directory.

Step 2.  Register the 50-096 DLL.  

  1. Right click on the Start icon and select Command Prompt (Admin).   Or if that does not work, search for Command Prompt and Run as Admin
  2. Type cd\Windows\SysWOW64 then press enter
  3. Type regSvr32 Model_50_096.dll and press enter

You should get a message that indicates that the Model_50_096.dll was registered.  

Step 3.  Set up the com port.

  1. Type Registry Editor in the search box and then run the registry editor as Admin
  2. Go to \\HKEY_Current_USER\Software\ULVAC_PHI\HARDWARE\X_RAY_CONTOL\
  3. Add a new string (which will add a new key)
  4. Name the new key ComPort
  5. Verify the type of key is REG_SZ
  6. Put in the com port number that you are connecting to the 50-096.  It needs to be COM (all caps) plus the com port number.  So for example, COM3.
  7. The 50-096 operates at 9600 baud with no parity and 8 data bits.

The 50-096 in now ready to operate with AugerScan.

Note: When first turned on, the Model 50-096 X-ray source power supply needs to be programmed to operate at 15 keV. To do this, perform the following steps:

1. Press the Local button under Control Select.

2. Press the Start button for the Water Pump.

3. Press the High Voltage button above the keypad.

4. Press the Display/Enter Setpoints button above the keypad. (LED should light.)

5. Press 1 – 5 – 0 – # on the keypad.

6. Press the remote button under Control Select. The 50-096 will retain the 15 keV setting until it is manually turned off or there is a power interruption.

Once this is set up AugerScan will automatically turn the 50-096 source on and off during and after acquisitions.  

Tip:   If you program in 12 or 13kV then that is what will be used when the 50-096 is turned on.

microCMA Software Update – New Features for Auger Multiplexes

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This past year there have been a number of new features added to CMapp – the application software for the microCMA. Most of these provide you with improved (and safer) control of your microCMA hardware. For example, there’s is now a “Dynamic Mode” feature that assists in automatically conditioning the multiplier.

The most significant addition to the CMapp software is the Multiplex Survey Region View.

Earlier versions of CMapp – like its AugerScan cousin – displayed Multiplex data in two ways – either individual survey region windows, or a bar graph representing the peak-to-peak or atomic concentration (a.c.) data.

The most recent version of CMapp (0.4) has an additional view, which displays the survey region data in one graph of kinetic energy vs. counts or concentration. It’s now much easier to visualize all of the survey data in one window. Additionally, the graph updates in real-time while acquiring, much like a single survey.

CMapp Mutiplex By Energy
Multiplex Region View (legend ordered by energy)

This latest feature was actually added to CMapp in a recent previous version, but we’ve updated it to provide the option to order data legend and atomic concentration table by energy, alphabetically, by descending atomic concentration, or by the order the regions were added to the acquisition.

CMapp Mutiplex By Energy
Multiplex Region View (legend ordered by atomic concentration)

You can change the order of regions in the legend (and in the optional atomic concentration annotation) in the View menu – choose the Options command, Graph tab:

CMapp View Options - Graph
CMapp View Options Dialog – Multiplex Legend Options

You can find more information about RBD’s microCMA and download the latest version of CMapp here.

We’ll be soon be updating our YouTube channel with more microCMA tutorial videos to help you get the most out of your compact Auger analyzer and CMapp software.