NAPAC2016 - List of Authors (Rao, T.)

Paper	Title	Page
WEPOB54	DC Photogun Gun Test for RHIC Low Energy Electron Cooler (LEReC).	1008
	D. Kayran, Z. Altinbas, D.R. Beavis, S. Bellavia, D. Bruno, M.R. Costanzo, A.V. Fedotov, D.M. Gassner, J. Halinski, K. Hamdi, J.P. Jamilkowski, J. Kewisch, C.J. Liaw, G.J. Mahler, T.A. Miller, S.K. Nayak, T. Rao, S. Seletskiy, B. Sheehy, J.E. Tuozzolo, Z. Zhao BNL, Upton, Long Island, New York, USA
	Funding: This work is supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE. Non-magnetized bunched electron cooling of low-energy RHIC requires electron beam energy in range of 1.6-2.6 MeV, with average current up to 45 mA, very small energy spread, and low emittance [1]. A 400 kV DC gun equipped with photocathode and laser delivery system will serve as a source of high-quality electron beam. Acceleration will be achieved by an SRF 704 MHz booster cavity and other RF components that are scheduled to be operational in early 2018. The DC gun testing in its installed location in RHIC will start in early 2017. During this stage we plan to test the critical equipment in close to operation conditions: laser beam delivery system, cathode QE lifetime, DC gun, beam instrumentation, high power beam dump system, and controls. In this paper, we describe the gun test set up, major components, and parameters to be achieved and measured during the gun beam test. [1] A. Fedotov. Bunched beam electron cooling for Low Energy RHIC operation. ICFA Beam Dynamics letter, No. 65, p. 22 (December 2014)
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WEPOB58	Cathode Puck Insertion System Design for the LEReC Photoemission DC Electron Gun	1021
	C.J. Liaw, V. De Monte, L. DeSanto, K. Hamdi, M. Mapes, T. Rao, A.N. Steszyn, J.E. Tuozzolo, J. Walsh BNL, Upton, Long Island, New York, USA K.W. Smolenski Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Funding: This work is supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. DOE. The operation of LEReC is to provide an electron cooling to improve the luminosity of the RHIC heavy ion beam at lower energies in a range of 2.5-25 GeV/nucleon. The electron beam is generated in a DC Electron Gun (DC gun) designed and built by the Cornell High Energy Synchrotron Source Group. This DC gun will operate around the clock for at least two weeks without maintenance. This paper presents the design of a reliable cathode puck insertion system, which includes a multi-pucks storage device, a transfer mechanism, a puck insertion device, a vacuum/control system, and a transport scheme.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEPOB58
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WEPOB59	Performance of CEC Pop Gun During Commissioning	1024
	I. Pinayev, W. Fu, Y. Hao, M. Harvey, T. Hayes, J.P. Jamilkowski, Y.C. Jing, P. K. Kankiya, D. Kayran, R. Kellermann, V. Litvinenko, G.J. Mahler, M. Mapes, K. Mernick, K. Mihara, T.A. Miller, G. Narayan, M.C. Paniccia, W.E. Pekrul, T. Rao, F. Severino, B. Sheehy, J. Skaritka, K.S. Smith, J.E. Tuozzolo, E. Wang, G. Wang, W. Xu, A. Zaltsman, Z. Zhao BNL, Upton, Long Island, New York, USA I. Petrushina SUNY SB, Stony Brook, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. The Coherent Electron Cooling Proof-of-Principle (CeC PoP) experiment employs a high-gradient CW photo-injector based on the superconducting RF cavity. Such guns operating at high accelerating gradients promise to revolutionize many sciences and applications. They can establish the basis for super-bright monochromatic X-ray and gamma ray sources, high luminosity hadron colliders, nuclear waste transmutation or a new generation of microchip production. In this paper we report on our operation of a superconducting RF electron gun with a high accelerating gradient at the CsK2Sb photo-cathode (i.e. ~ 20 MV/m) generating a record-high bunch charge (above 4 nC). We give short description of the system and then detail our experimental results.
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WEPOB60	Commissioning of CeC PoP Accelerator	1027
	I. Pinayev, Z. Altinbas, J.C.B. Brutus, A.J. Curcio, A. Di Lieto, C. Folz, W. Fu, D.M. Gassner, Y. Hao, M. Harvey, T. Hayes, R.L. Hulsart, J.P. Jamilkowski, Y.C. Jing, P. K. Kankiya, D. Kayran, R. Kellermann, V. Litvinenko, G.J. Mahler, M. Mapes, K. Mernick, R.J. Michnoff, K. Mihara, T.A. Miller, G. Narayan, P. Orfin, M.C. Paniccia, D. Phillips, T. Rao, F. Severino, B. Sheehy, J. Skaritka, L. Smart, K.S. Smith, V. Soria, Z. Sorrell, R. Than, J.E. Tuozzolo, E. Wang, G. Wang, B. P. Xiao, W. Xu, A. Zaltsman, Z. Zhao BNL, Upton, Long Island, New York, USA I. Petrushina SUNY SB, Stony Brook, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. Coherent electron cooling is new cooling technique to be tested at BNL. Presently we are in the commissioning stage of the accelerator system. In this paper we present status of various systems and achieved beam parameters as well as operational experience. Near term future plans are also discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEPOB60
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WEPOB67	K2CsSb Photocathode Performance in QWR SRF Gun	1042
	E. Wang, Y. Hao, Y.C. Jing, V. Litvinenko, I. Pinayev, T. Rao, J. Skaritka, G. Wang, T. Xin BNL, Upton, Long Island, New York, USA
	In 2016 run of Coherent Electron Cooling, we have successfully tested the performance of a number of K2CsSb cathodes. These cathodes with QE of 6%-10% were fabricated in Instrumentation Division, a few miles away, transported to RHIC tunnel under UHV conditions, attached to the CeC gun, kept in storage, and inserted in the gun as needed. A maximum bunch charge of 4.6 nC was generated in the gun when the QE was 1.8 %. With careful conditioning at increasing accelerating fields, it was possible to maintain the QE of several cathodes for more than a week. For the cathodes that experienced degradation, the primary cause was multipacting when the power into the gun was increased. In the initial runs, the entire 20 mm substrate face was coated with the cathode material causing cathode induced multipacting. For subsequent measurements, the substrate was masked to coat only the central 9 mm of the substrate. By optimizing the procedure for boosting the power to the gun and covering all viewports to minimize dark current, we were able to minimize QE degradation. In this paper we discuss the cathode preparation, transfer to the gun and operational experience with the cathodes in 112 MHz gun.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEPOB67
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THPOA41	Simulations of Hole Injection in Diamond Detectors	1184
	G.I. Bell, D.A. Dimitrov, C.D. Zhou Tech-X, Boulder, Colorado, USA I. Ben-Zvi, M. Gaowei, T. Rao, J. Smedley BNL, Upton, Long Island, New York, USA E.M. Muller SBU, Stony Brook, New York, USA
	Funding: This work is supported by the US DOE Office of Science, department of Basic Energy Sciences, under grant DE-SC0007577. We present simulations of a semiconductor beam detector using the code VSIM. The 3D simulations involve the movement and scattering of electrons and holes in the semiconductor, voltages which may be applied to external contacts, and self-consistent electrostatic fields inside the device. Electrons may experience a Schottky barrier when attempting to move from the semiconductor into a metal contact. The strong field near the contact, due to trapped electrons, can result in hole injection into the semiconductor due to transmission of electrons from the valence band of the semiconductor into the metal contact. Injected holes are transported in the applied field leading to current through the detector. We compare our simulation results with experimental results from a prototype diamond X-ray detector.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-THPOA41
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Paper

Title

Page

DC Photogun Gun Test for RHIC Low Energy Electron Cooler (LEReC).

1008

D. Kayran, Z. Altinbas, D.R. Beavis, S. Bellavia, D. Bruno, M.R. Costanzo, A.V. Fedotov, D.M. Gassner, J. Halinski, K. Hamdi, J.P. Jamilkowski, J. Kewisch, C.J. Liaw, G.J. Mahler, T.A. Miller, S.K. Nayak, T. Rao, S. Seletskiy, B. Sheehy, J.E. Tuozzolo, Z. Zhao
BNL, Upton, Long Island, New York, USA

Funding: This work is supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE.
Non-magnetized bunched electron cooling of low-energy RHIC requires electron beam energy in range of 1.6-2.6 MeV, with average current up to 45 mA, very small energy spread, and low emittance [1]. A 400 kV DC gun equipped with photocathode and laser delivery system will serve as a source of high-quality electron beam. Acceleration will be achieved by an SRF 704 MHz booster cavity and other RF components that are scheduled to be operational in early 2018. The DC gun testing in its installed location in RHIC will start in early 2017. During this stage we plan to test the critical equipment in close to operation conditions: laser beam delivery system, cathode QE lifetime, DC gun, beam instrumentation, high power beam dump system, and controls. In this paper, we describe the gun test set up, major components, and parameters to be achieved and measured during the gun beam test.
[1] A. Fedotov. Bunched beam electron cooling for Low Energy RHIC operation. ICFA Beam Dynamics letter, No. 65, p. 22 (December 2014)

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reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEPOB54

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WEPOB58

Cathode Puck Insertion System Design for the LEReC Photoemission DC Electron Gun

1021

C.J. Liaw, V. De Monte, L. DeSanto, K. Hamdi, M. Mapes, T. Rao, A.N. Steszyn, J.E. Tuozzolo, J. Walsh
BNL, Upton, Long Island, New York, USA
K.W. Smolenski
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: This work is supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. DOE.
The operation of LEReC is to provide an electron cooling to improve the luminosity of the RHIC heavy ion beam at lower energies in a range of 2.5-25 GeV/nucleon. The electron beam is generated in a DC Electron Gun (DC gun) designed and built by the Cornell High Energy Synchrotron Source Group. This DC gun will operate around the clock for at least two weeks without maintenance. This paper presents the design of a reliable cathode puck insertion system, which includes a multi-pucks storage device, a transfer mechanism, a puck insertion device, a vacuum/control system, and a transport scheme.

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reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEPOB58

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WEPOB59

Performance of CEC Pop Gun During Commissioning

1024

I. Pinayev, W. Fu, Y. Hao, M. Harvey, T. Hayes, J.P. Jamilkowski, Y.C. Jing, P. K. Kankiya, D. Kayran, R. Kellermann, V. Litvinenko, G.J. Mahler, M. Mapes, K. Mernick, K. Mihara, T.A. Miller, G. Narayan, M.C. Paniccia, W.E. Pekrul, T. Rao, F. Severino, B. Sheehy, J. Skaritka, K.S. Smith, J.E. Tuozzolo, E. Wang, G. Wang, W. Xu, A. Zaltsman, Z. Zhao
BNL, Upton, Long Island, New York, USA
I. Petrushina
SUNY SB, Stony Brook, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
The Coherent Electron Cooling Proof-of-Principle (CeC PoP) experiment employs a high-gradient CW photo-injector based on the superconducting RF cavity. Such guns operating at high accelerating gradients promise to revolutionize many sciences and applications. They can establish the basis for super-bright monochromatic X-ray and gamma ray sources, high luminosity hadron colliders, nuclear waste transmutation or a new generation of microchip production. In this paper we report on our operation of a superconducting RF electron gun with a high accelerating gradient at the CsK2Sb photo-cathode (i.e. ~ 20 MV/m) generating a record-high bunch charge (above 4 nC). We give short description of the system and then detail our experimental results.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEPOB59

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WEPOB60

Commissioning of CeC PoP Accelerator

1027

I. Pinayev, Z. Altinbas, J.C.B. Brutus, A.J. Curcio, A. Di Lieto, C. Folz, W. Fu, D.M. Gassner, Y. Hao, M. Harvey, T. Hayes, R.L. Hulsart, J.P. Jamilkowski, Y.C. Jing, P. K. Kankiya, D. Kayran, R. Kellermann, V. Litvinenko, G.J. Mahler, M. Mapes, K. Mernick, R.J. Michnoff, K. Mihara, T.A. Miller, G. Narayan, P. Orfin, M.C. Paniccia, D. Phillips, T. Rao, F. Severino, B. Sheehy, J. Skaritka, L. Smart, K.S. Smith, V. Soria, Z. Sorrell, R. Than, J.E. Tuozzolo, E. Wang, G. Wang, B. P. Xiao, W. Xu, A. Zaltsman, Z. Zhao
BNL, Upton, Long Island, New York, USA
I. Petrushina
SUNY SB, Stony Brook, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Coherent electron cooling is new cooling technique to be tested at BNL. Presently we are in the commissioning stage of the accelerator system. In this paper we present status of various systems and achieved beam parameters as well as operational experience. Near term future plans are also discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEPOB60

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WEPOB67

K2CsSb Photocathode Performance in QWR SRF Gun

1042

E. Wang, Y. Hao, Y.C. Jing, V. Litvinenko, I. Pinayev, T. Rao, J. Skaritka, G. Wang, T. Xin
BNL, Upton, Long Island, New York, USA

In 2016 run of Coherent Electron Cooling, we have successfully tested the performance of a number of K2CsSb cathodes. These cathodes with QE of 6%-10% were fabricated in Instrumentation Division, a few miles away, transported to RHIC tunnel under UHV conditions, attached to the CeC gun, kept in storage, and inserted in the gun as needed. A maximum bunch charge of 4.6 nC was generated in the gun when the QE was 1.8 %. With careful conditioning at increasing accelerating fields, it was possible to maintain the QE of several cathodes for more than a week. For the cathodes that experienced degradation, the primary cause was multipacting when the power into the gun was increased. In the initial runs, the entire 20 mm substrate face was coated with the cathode material causing cathode induced multipacting. For subsequent measurements, the substrate was masked to coat only the central 9 mm of the substrate. By optimizing the procedure for boosting the power to the gun and covering all viewports to minimize dark current, we were able to minimize QE degradation. In this paper we discuss the cathode preparation, transfer to the gun and operational experience with the cathodes in 112 MHz gun.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEPOB67

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THPOA41

Simulations of Hole Injection in Diamond Detectors

1184

G.I. Bell, D.A. Dimitrov, C.D. Zhou
Tech-X, Boulder, Colorado, USA
I. Ben-Zvi, M. Gaowei, T. Rao, J. Smedley
BNL, Upton, Long Island, New York, USA
E.M. Muller
SBU, Stony Brook, New York, USA

Funding: This work is supported by the US DOE Office of Science, department of Basic Energy Sciences, under grant DE-SC0007577.
We present simulations of a semiconductor beam detector using the code VSIM. The 3D simulations involve the movement and scattering of electrons and holes in the semiconductor, voltages which may be applied to external contacts, and self-consistent electrostatic fields inside the device. Electrons may experience a Schottky barrier when attempting to move from the semiconductor into a metal contact. The strong field near the contact, due to trapped electrons, can result in hole injection into the semiconductor due to transmission of electrons from the valence band of the semiconductor into the metal contact. Injected holes are transported in the applied field leading to current through the detector. We compare our simulation results with experimental results from a prototype diamond X-ray detector.

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reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-THPOA41

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