IBIC2017 - List of Authors (Fisher, A.S.)

Paper	Title	Page
TUPCC09	Electron Bunch Pattern Monitoring via Single Photon Counting at SPEAR3	168
	B. Xu, E. Carranza, A. Chen, S. Condamoor, W.J. Corbett, A.S. Fisher SLAC, Menlo Park, California, USA
	In recent years the synchrotron radiation program at SPEAR3 has moved increasingly toward laser/x-ray pump-probe experiments which utilize a single timing ‘probe' bunch isolated by 50ns dark space ahead and behind the bunch. In order to quantify bunch purity in the region near the timing bunch, time-correlated single-photon counting is used. In this paper we investigate methods to optimize data acquisition speed and improve measurement resolution in the region near the timing bunch through data analysis and fast signal gating. Integration of the measured data into the EPICS database is reported.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2017-TUPCC09
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TH1AB1	Field Emission in Superconducting Accelerators: Instrumented Measurements for Its Understanding and Mitigation	470
	R.L. Geng, A. Freyberger, R.A. Legg, R. Suleiman JLab, Newport News, Virginia, USA A.S. Fisher SLAC, Menlo Park, California, USA
	Several new accelerator projects are adopting superconducting accelerator technology. When accelerating cavities maintain high RF gradients, field emission, the emission of electrons from cavity walls, can occur and may impact operational cavity gradient, radiological environment via activated components, and reliability. In this talk, we will discuss instrumented measurements of field emission from the two 1.1 GeV superconducting continuous wave (CW) linacs in CEBAF. The goal is to improve the understanding of field emission sources originating from cryomodule production, installation and operation. Such basic knowledge is needed in guiding field emission control, mitigation, and reduction toward high gradient and reliable operation of superconducting accelerators.
	Slides TH1AB1 [7.301 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2017-TH1AB1
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TH1AB2	Beam Containment and Machine Protection for LCLS-2	478
	A.S. Fisher, C.I. Clarke, R.C. Field, J.C. Frisch, R.T. Herbst, R.A. Kadyrov, B.D. McKee, F. Tao, J.J. Welch SLAC, Menlo Park, California, USA
	The first km of the 3-km SLAC linac is being replaced by LCLS-2, a superconducting linac with continuous RF and a maximum beam rate of 1 MHz. The beam will have an energy of 4 GeV and a maximum power of 250 kW, with an upgrade to 8 GeV and 1 MW in planning. The beam will be transported through the accelerator tunnel, passing over the future 1-km FACET-2 and the existing 1-km LCLS linacs, both using normal-conducting copper cavities at repetition rates of up to 120 Hz. The LCLS and LCLS-2 beams will continue together through the Beam Transport Hall to two new undulators, for hard and soft x rays. Kickers will direct individual pulses to either undulator or to a dump. The high power in the beam and potentially in cavity field emission necessitate integrating losses over 500 ms but responding within 0.1 ms. A capacitor for integration and a comparator for the threshold give a simple and robust approach over a wide dynamic range. We plan both long loss monitors covering regions of typically 100 m and point monitors. In regions with two or more beamlines, the system will attempt to determine the line that caused a loss, so that only one is shut off.
	Slides TH1AB2 [4.182 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2017-TH1AB2
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Electron Bunch Pattern Monitoring via Single Photon Counting at SPEAR3

168

B. Xu, E. Carranza, A. Chen, S. Condamoor, W.J. Corbett, A.S. Fisher
SLAC, Menlo Park, California, USA

In recent years the synchrotron radiation program at SPEAR3 has moved increasingly toward laser/x-ray pump-probe experiments which utilize a single timing ‘probe' bunch isolated by 50ns dark space ahead and behind the bunch. In order to quantify bunch purity in the region near the timing bunch, time-correlated single-photon counting is used. In this paper we investigate methods to optimize data acquisition speed and improve measurement resolution in the region near the timing bunch through data analysis and fast signal gating. Integration of the measured data into the EPICS database is reported.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2017-TUPCC09

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TH1AB1

Field Emission in Superconducting Accelerators: Instrumented Measurements for Its Understanding and Mitigation

470

R.L. Geng, A. Freyberger, R.A. Legg, R. Suleiman
JLab, Newport News, Virginia, USA
A.S. Fisher
SLAC, Menlo Park, California, USA

Several new accelerator projects are adopting superconducting accelerator technology. When accelerating cavities maintain high RF gradients, field emission, the emission of electrons from cavity walls, can occur and may impact operational cavity gradient, radiological environment via activated components, and reliability. In this talk, we will discuss instrumented measurements of field emission from the two 1.1 GeV superconducting continuous wave (CW) linacs in CEBAF. The goal is to improve the understanding of field emission sources originating from cryomodule production, installation and operation. Such basic knowledge is needed in guiding field emission control, mitigation, and reduction toward high gradient and reliable operation of superconducting accelerators.

Slides TH1AB1 [7.301 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2017-TH1AB1

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TH1AB2

Beam Containment and Machine Protection for LCLS-2

478

A.S. Fisher, C.I. Clarke, R.C. Field, J.C. Frisch, R.T. Herbst, R.A. Kadyrov, B.D. McKee, F. Tao, J.J. Welch
SLAC, Menlo Park, California, USA

The first km of the 3-km SLAC linac is being replaced by LCLS-2, a superconducting linac with continuous RF and a maximum beam rate of 1 MHz. The beam will have an energy of 4 GeV and a maximum power of 250 kW, with an upgrade to 8 GeV and 1 MW in planning. The beam will be transported through the accelerator tunnel, passing over the future 1-km FACET-2 and the existing 1-km LCLS linacs, both using normal-conducting copper cavities at repetition rates of up to 120 Hz. The LCLS and LCLS-2 beams will continue together through the Beam Transport Hall to two new undulators, for hard and soft x rays. Kickers will direct individual pulses to either undulator or to a dump. The high power in the beam and potentially in cavity field emission necessitate integrating losses over 500 ms but responding within 0.1 ms. A capacitor for integration and a comparator for the threshold give a simple and robust approach over a wide dynamic range. We plan both long loss monitors covering regions of typically 100 m and point monitors. In regions with two or more beamlines, the system will attempt to determine the line that caused a loss, so that only one is shut off.

Slides TH1AB2 [4.182 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2017-TH1AB2

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)