Behavior of the SNS Front End Emittance Device

The SNS Front End 2.5 MeV Emittance Device was first tested with beam from the RFQ on February 1, 2002. The hardware is simple in concept, but has some non-obvious behavior that needs to be understood before the output data can be used to construct renderings of phase space intensities, and compute emittances. This note documents the wiring, channel mapping, offset subtraction, channel sensitivity calibration, and probable slit scattering.

You may download this Tech note in its entirety in PostScript (216K) or PDF (280K). The PostScript version can be printed on any PostScript printer, or previewed with the Ghostscript suite. The PDF version can be viewed and printed using any of xpdf, the Ghostscript suite, or Adobe Acrobat (untested).

You may download a kit (16K) that allows a complete regeneration of the note. For space reasons, this kit does not include the three data files archived from the run, so you need to find those separately:

• MEBT_Dia0100.mdals
• MEBT_Dia0133.mdals
• MEBT_Dia0134.mdals

You may look at the individual pieces, where all the figures are given in .eps form:

• LaTeX source file
• Table 1. Channel cross reference
• Figure 1. Schematic of one preamplifier channel
• Figure 2. Example current waveforms
• Figure 3. Wire signals for fixed slit
• Figure 4. Signal strengths measured for each channel
• Figure 5. Deviations of wire centroid from nominal 0.5 mm pitch
• Figure 6. Broad tail in collected current

Larry Doolittle
February 11, 2002