Phase noise reduction and photoelectron acceleration in a high-Q RF gun

Landahl, Eric C.; Hartemann, F. V.; Sage, G. P. Le; White, William E.; Baldis, H. A.; Bennett, C.V.; Luhmann, Neville C.; Ho, C. H.

doi:10.1109/27.700840

Cited by 9 publications

(2 citation statements)

References 18 publications

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“…Such approaches are appropriate to the phases of dark current modeling [9,15,16,20,21]) prior to large temperature excursions, but their applicability afterwards is undermined by (i) when temperatures at the emission site approach the melting point of the metals (emission is thermal field rather than FN); (ii) when migration of material results in nanoprotrusions that dynamically grow but whose size precludes their adequate consideration by numerical means; and (iii) when the only acknowledgment of geometry is through the positing of a field enhancement ''beta factor'' without considering its companion effect on the ''notional'' emission area [22]. That such considerations matter is supported by treatments in which the thermal-field emission for multidimensional structures is numerically found [23,24] and which capture effects absent in the analytical approaches.…”

Section: Introductionmentioning

confidence: 99%

Electron emission contributions to dark current and its relation to microscopic field enhancement and heating in accelerator structures

Jensen

Lau

Feldman

et al. 2008

Phys. Rev. ST Accel. Beams

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Analytically tractable models of thermal-field emission, field enhancement, and heating mechanisms (Nottingham and resistive) are developed and combined to make estimates of the fields and temperatures that accompany the development and growth of asperities. The relation of asperity dimensions to dark current is discussed in two experimentally motivated examples. The hypothetical relation of microscopic sources of dark current and heating to breakdown is discussed in the context of Nottingham and resistive heating. The latter are estimated using a general thermal-field methodology. A point-charge model is used to find field enhancement factors. Last, a thermal model is used to estimate the temperature dependence of the resistivity and thermal conductivity. Together, these models suggest that conditions can arise in which the temperature at the apex of an asperity can experience growth and contribute to melting or fracture (or both), and that Nottingham heating generally dominates the resistive heating term.

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Section: Introductionmentioning

confidence: 99%

Electron emission contributions to dark current and its relation to microscopic field enhancement and heating in accelerator structures

Jensen

Lau

Feldman

et al. 2008

Phys. Rev. ST Accel. Beams

View full text Add to dashboard Cite

show abstract

“…The first X-band rf gun was fabricated, cold tested and brazed at SRRC and was delivered to UC Davis at the Lawrence Livermore National Laboratory (LLNL) site in April, 1997. The gun was installed and characterized by the research personnel from both groups [2], [3].…”

Section: Introductionmentioning

confidence: 99%