IPAC2017 - List of Authors (Kewisch, J.)

Paper	Title	Page
TUPAB142	Tracking of Electrons Created at Wrong RF Phases in the RHIC Low Energy Cooler	1666
	J. Kewisch, A.V. Fedotov, D. Kayran, S. Seletskiy BNL, Upton, Long Island, New York, USA
	Funding: Work supported by the US Department of Energy under contract No. DE-SC0012704. The RHIC Low Energy Cooler will be based on a 400 keV DC electron gun with a photo-cathode and a 2.2 MeV SRF booster cavity. Electron that leave the cathode at the wrong time may be decelerated and turned around in the booster and return to the cathode with energies up to 1 MeV. On the way back these electron will encounter the defocussing EM fields up to nine following electron bunches. Such electrons may be created for various reasons: Cosmic rays, stray laser light including a catastrophic failure of the laser timing system or as secondaries of returning electrons. We present tracking results from the GPT program* and discuss the consequences for the machine protection system. * www.pulsar.nl
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPAB142
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TUPAB143	Dependence of LEReC Beam Energy Spread on Photocathode Laser Modulation	1669
	S. Seletskiy, M. Blaskiewicz, A.V. Fedotov, D. Kayran, J. Kewisch, M.G. Minty, B. Sheehy, Z. Zhao BNL, Upton, Long Island, New York, USA B. Sheehy Sheehy Scientific Consulting, Wading River, New York, USA
	Present requirements to the photocathode DC gun of the low energy RHIC electron cooling (LEReC) project is to produce 100 ps long bunch of electrons with 130 pC charge. The laser pulse of required length will be produced with the stacking of multiple few picosecond long sub-pulses. Depending on the choice of the laser sub-pulse length and on the relative delay between these sub-pulses one can obtain laser pulse with various longitudinal intensity modulations. The longitudinal modulation of laser intensity creates longitudinal modulation of electron bunch charge. Such modulation is known to cause the growth of e-beam uncorrelated energy spread in photoinjectors - the effect we would like to avoid. In this paper we estimate growth of e-beam energy spread due to its initial density modulation and set requirements to the maximum allowable depth of longitudinal modulation of photocathode laser intensity.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPAB143
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TUPAB145	Alignment of Electron and Ion Beam Trajectories in Non-Magnetized Electron Cooler	1672
	S. Seletskiy, M. Blaskiewicz, A.V. Fedotov, D. Kayran, J. Kewisch, R.J. Michnoff, I. Pinayev BNL, Upton, Long Island, New York, USA
	The cooling section (CS) of the low energy RHIC electron cooler (LEReC) consists of two 20 m long parts each containing six solenoids with trajectory correctors placed inside the solenoids and the BPMs located downstream of each solenoid. The solenoids are used to minimize the scalloping of the electron beam envelope. To obtain the cooling it is required to keep the overall RMS electron angles in the cooling section below 100 urad. Possible mechanical misalignment, such as shift and inclination of the CS solenoids can cause an unacceptable misalignment of the e-beam trajectory with respect to the ideal trajectory set by ions. Therefore, it is critical to perform a beam based alignment of the CS solenoids. In this paper we suggest a procedure for such an alignment.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPAB145
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Paper

Title

Page

Tracking of Electrons Created at Wrong RF Phases in the RHIC Low Energy Cooler

1666

J. Kewisch, A.V. Fedotov, D. Kayran, S. Seletskiy
BNL, Upton, Long Island, New York, USA

Funding: Work supported by the US Department of Energy under contract No. DE-SC0012704.
The RHIC Low Energy Cooler will be based on a 400 keV DC electron gun with a photo-cathode and a 2.2 MeV SRF booster cavity. Electron that leave the cathode at the wrong time may be decelerated and turned around in the booster and return to the cathode with energies up to 1 MeV. On the way back these electron will encounter the defocussing EM fields up to nine following electron bunches. Such electrons may be created for various reasons: Cosmic rays, stray laser light including a catastrophic failure of the laser timing system or as secondaries of returning electrons. We present tracking results from the GPT program* and discuss the consequences for the machine protection system.
* www.pulsar.nl

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPAB142

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

TUPAB143

Dependence of LEReC Beam Energy Spread on Photocathode Laser Modulation

1669

S. Seletskiy, M. Blaskiewicz, A.V. Fedotov, D. Kayran, J. Kewisch, M.G. Minty, B. Sheehy, Z. Zhao
BNL, Upton, Long Island, New York, USA
B. Sheehy
Sheehy Scientific Consulting, Wading River, New York, USA

Present requirements to the photocathode DC gun of the low energy RHIC electron cooling (LEReC) project is to produce 100 ps long bunch of electrons with 130 pC charge. The laser pulse of required length will be produced with the stacking of multiple few picosecond long sub-pulses. Depending on the choice of the laser sub-pulse length and on the relative delay between these sub-pulses one can obtain laser pulse with various longitudinal intensity modulations. The longitudinal modulation of laser intensity creates longitudinal modulation of electron bunch charge. Such modulation is known to cause the growth of e-beam uncorrelated energy spread in photoinjectors - the effect we would like to avoid. In this paper we estimate growth of e-beam energy spread due to its initial density modulation and set requirements to the maximum allowable depth of longitudinal modulation of photocathode laser intensity.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPAB143

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

TUPAB145

Alignment of Electron and Ion Beam Trajectories in Non-Magnetized Electron Cooler

1672

S. Seletskiy, M. Blaskiewicz, A.V. Fedotov, D. Kayran, J. Kewisch, R.J. Michnoff, I. Pinayev
BNL, Upton, Long Island, New York, USA

The cooling section (CS) of the low energy RHIC electron cooler (LEReC) consists of two 20 m long parts each containing six solenoids with trajectory correctors placed inside the solenoids and the BPMs located downstream of each solenoid. The solenoids are used to minimize the scalloping of the electron beam envelope. To obtain the cooling it is required to keep the overall RMS electron angles in the cooling section below 100 urad. Possible mechanical misalignment, such as shift and inclination of the CS solenoids can cause an unacceptable misalignment of the e-beam trajectory with respect to the ideal trajectory set by ions. Therefore, it is critical to perform a beam based alignment of the CS solenoids. In this paper we suggest a procedure for such an alignment.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPAB145

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