Recent progress at SLAC extracting high charge from highly polarized photocathodes for future-collider applications

J. E. Clendenin; A. Brachmann; E. L. Garwin; S. Harvey; J. Jiang; R. E. Kirby; D. A. Luh; T. Maruyama; R. Prepost; C. Y. Prescott; J. L. Turner

doi:10.1016/j.nima.2004.08.089

Recent progress at SLAC extracting high charge from highly polarized photocathodes for future-collider applications

J. E. Clendenin
, A. Brachmann
, E. L. Garwin
, S. Harvey
, J. Jiang
, R. E. Kirby
, D. A. Luh
, T. Maruyama
, R. Prepost
, C. Y. Prescott
, J. L. Turner

Department of Physics

Research output: Contribution to journal › Conference article › peer-review

10 Scopus citations

Abstract

Future colliders such as NLC and JLC will require a highly polarized macropulse with charge that is more than an order of magnitude beyond that which could be produced for the SLC. The maximum charge from the SLC uniformly doped GaAs photocathode was limited by the surface charge limit (SCL). The SCL effect can be overcome by using an extremely high (≥1019cm-3) surface dopant concentration. When combined with a medium dopant concentration in the majority of the active layer (to avoid depolarization), the surface concentration has been found to degrade during normal heat cleaning (1 h at 600°C). The Be dopant as typically used in an MBE-grown superlattice cathode is especially susceptible to this effect compared to Zn or C dopant. Some relief can be found by lowering the cleaning temperature, but the long-term general solution appears to be atomic hydrogen cleaning.

Original language	English
Pages (from-to)	308-311
Number of pages	4
Journal	Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
Volume	536
Issue number	3
DOIs	https://doi.org/10.1016/j.nima.2004.08.089
State	Published - 11 Jan 2005
Event	Polarized Sources and Targets for the 21st Century - Novosibirsk, Russian Federation Duration: 22 Sep 2003 → 26 Sep 2003

Keywords

Photocathodes
Photoemission
Semiconductors
Surface charge limit

Access to Document

10.1016/j.nima.2004.08.089

Cite this

Clendenin, J. E., Brachmann, A., Garwin, E. L., Harvey, S., Jiang, J., Kirby, R. E., Luh, D. A., Maruyama, T., Prepost, R., Prescott, C. Y., & Turner, J. L. (2005). Recent progress at SLAC extracting high charge from highly polarized photocathodes for future-collider applications. Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 536(3), 308-311. https://doi.org/10.1016/j.nima.2004.08.089

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title = "Recent progress at SLAC extracting high charge from highly polarized photocathodes for future-collider applications",

abstract = "Future colliders such as NLC and JLC will require a highly polarized macropulse with charge that is more than an order of magnitude beyond that which could be produced for the SLC. The maximum charge from the SLC uniformly doped GaAs photocathode was limited by the surface charge limit (SCL). The SCL effect can be overcome by using an extremely high (≥1019cm-3) surface dopant concentration. When combined with a medium dopant concentration in the majority of the active layer (to avoid depolarization), the surface concentration has been found to degrade during normal heat cleaning (1 h at 600°C). The Be dopant as typically used in an MBE-grown superlattice cathode is especially susceptible to this effect compared to Zn or C dopant. Some relief can be found by lowering the cleaning temperature, but the long-term general solution appears to be atomic hydrogen cleaning.",

keywords = "Photocathodes, Photoemission, Semiconductors, Surface charge limit",

author = "Clendenin, \{J. E.\} and A. Brachmann and Garwin, \{E. L.\} and S. Harvey and J. Jiang and Kirby, \{R. E.\} and Luh, \{D. A.\} and T. Maruyama and R. Prepost and Prescott, \{C. Y.\} and Turner, \{J. L.\}",

note = "Funding Information: Work supported by Department of Energy contract DE-AC03-76SF00515. ; Polarized Sources and Targets for the 21st Century ; Conference date: 22-09-2003 Through 26-09-2003",

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Clendenin, JE, Brachmann, A, Garwin, EL, Harvey, S, Jiang, J, Kirby, RE, Luh, DA, Maruyama, T, Prepost, R, Prescott, CY & Turner, JL 2005, 'Recent progress at SLAC extracting high charge from highly polarized photocathodes for future-collider applications', Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, vol. 536, no. 3, pp. 308-311. https://doi.org/10.1016/j.nima.2004.08.089

Recent progress at SLAC extracting high charge from highly polarized photocathodes for future-collider applications. / Clendenin, J. E.; Brachmann, A.; Garwin, E. L. et al.
In: Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 536, No. 3, 11.01.2005, p. 308-311.

Research output: Contribution to journal › Conference article › peer-review

TY - JOUR

T1 - Recent progress at SLAC extracting high charge from highly polarized photocathodes for future-collider applications

AU - Clendenin, J. E.

AU - Brachmann, A.

AU - Garwin, E. L.

AU - Harvey, S.

AU - Jiang, J.

AU - Kirby, R. E.

AU - Luh, D. A.

AU - Maruyama, T.

AU - Prepost, R.

AU - Prescott, C. Y.

AU - Turner, J. L.

N1 - Funding Information: Work supported by Department of Energy contract DE-AC03-76SF00515.

PY - 2005/1/11

Y1 - 2005/1/11

N2 - Future colliders such as NLC and JLC will require a highly polarized macropulse with charge that is more than an order of magnitude beyond that which could be produced for the SLC. The maximum charge from the SLC uniformly doped GaAs photocathode was limited by the surface charge limit (SCL). The SCL effect can be overcome by using an extremely high (≥1019cm-3) surface dopant concentration. When combined with a medium dopant concentration in the majority of the active layer (to avoid depolarization), the surface concentration has been found to degrade during normal heat cleaning (1 h at 600°C). The Be dopant as typically used in an MBE-grown superlattice cathode is especially susceptible to this effect compared to Zn or C dopant. Some relief can be found by lowering the cleaning temperature, but the long-term general solution appears to be atomic hydrogen cleaning.

AB - Future colliders such as NLC and JLC will require a highly polarized macropulse with charge that is more than an order of magnitude beyond that which could be produced for the SLC. The maximum charge from the SLC uniformly doped GaAs photocathode was limited by the surface charge limit (SCL). The SCL effect can be overcome by using an extremely high (≥1019cm-3) surface dopant concentration. When combined with a medium dopant concentration in the majority of the active layer (to avoid depolarization), the surface concentration has been found to degrade during normal heat cleaning (1 h at 600°C). The Be dopant as typically used in an MBE-grown superlattice cathode is especially susceptible to this effect compared to Zn or C dopant. Some relief can be found by lowering the cleaning temperature, but the long-term general solution appears to be atomic hydrogen cleaning.

KW - Photocathodes

KW - Photoemission

KW - Semiconductors

KW - Surface charge limit

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JO - Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment

JF - Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment

IS - 3

T2 - Polarized Sources and Targets for the 21st Century

Y2 - 22 September 2003 through 26 September 2003

ER -

Clendenin JE, Brachmann A, Garwin EL, Harvey S, Jiang J, Kirby RE et al. Recent progress at SLAC extracting high charge from highly polarized photocathodes for future-collider applications. Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. 2005 Jan 11;536(3):308-311. doi: 10.1016/j.nima.2004.08.089

Recent progress at SLAC extracting high charge from highly polarized photocathodes for future-collider applications

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Keywords

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