Model 642 X-ray Source Interchangeable solid anodes Emission follows anode valence band structure Accelerated filament electron source Does not require water cooling or flow of gas Extremely stable, debris free, electrically quiet Dual balanced output for calibrations Available complete with power supply

The Model 642 was originally developed for use in the radiometric calibration of grazing incidence spectrometers. The design features make it a useful source for many applications. A special feature of this source is that there are two equivalent output beams. These originate from two views of the single emitting spot where the electron beam from the single hairpin filament collides with the interchangeable anode. The spot is about 1mm diameter.

All the testing of the source has been done with a 90 degree separation between beams. In this geometry outputs are equal to +/-2% at Mg-K, O-K, C-K and B-K. Source output at these emissions reached 10^11 photons sec^-1 sterradian^-1 at less than the maximum anode load (5 Watts.)

Some examples of available anodes: (many others available, please inquire)
Magnesium L/M for 25.1nm (49.3eV)
Aluminum L/M for 17.1nm (72.4eV)
Silicon L/M for 13.5nm (91.5eV)
Beryllium K for 11.4nm (108.5)
Boron K for 6.7nm (183.3eV)
Carbon K for 4.4nm (277eV)
Oxygen K for 2.3nm (524eV)
Magnesium K for 0.98nm (1253.6eV) (this is about the low limit for our grating based instruments...)

Data above was collected with direct detection CCD. We used the Model 251MX Spectrograph with easily exchanged flat field gratings to collect these spectra.

The source mounts on a 2-3/4" all metal seal flange. A 'branch' housing is available for ready access to the two output beams. The source can be baked to 350 degrees C and is provided with spare anodes and filament assemblies. The source controller is also included and provides a cathode heating supply, self-bias control, metering of the heater current and cables. We can also provide a suitable 10 kV power supply (max beam current 1 mA) for a complete, ready to use source system.

Calibration and reflectance work can be performed with the Model 248/310G. Built in reverse, the light source is mounted on the scanning carriage. Tune the monochromator to a specific wavelength and have a good, fixed trajectory exit beam for calibration and reflectometry applications. The light sources used with the monochromator set up this way should be compact. Good choices include the Model 642 soft x-ray source and the hollow cathode, Model 629. The latter is better for emission lines from inert gases from 30 to 100nm.