LINAC2016 - Classification: 3 Technology / 3I Other Technology

Paper	Title	Page
THPRC029	Comissioning Results for a Subharmonic Buncher at REA	833
SPWR035	use link to see paper's listing under its alternate paper code
	D.M. Alt, J.F. Brandon, S.W. Krause, A. Lapierre, D.G. Morris, S. Nash, N.R. Usher, A.C.C. Villari, S.J. Williams, S. Zhao FRIB, East Lansing, USA M.J. Syphers Northern Illinois University, DeKalb, Illinois, USA
	Funding: NSF PHY-1102511 The reaccelerator facility (ReA) at the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University (MSU) offers a unique capability to study reactions with low-energy beams of rare isotopes. A beam from the coupled cyclotron facility is stopped in a gas stopping system, charge bred in an Electron Beam Ion Trap (EBIT), and then reaccelerated in a compact superconducting LINAC. The original beam repetition rate at the ReA targets was the same as the LINAC RF frequency of 80.5 MHz. In order to add the capability to bunch at a lower frequency (desirable for many types of experiments using time of flight data acquisitions) a 16.1 MHz buncher has been designed, constructed, and commissioned. This paper reports the results of the commissioning of the device, and outlines some future avenues for further improvement of the properties of the bunched beam.
	Poster THPRC029 [0.903 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPRC029
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THPRC030	Plasma Window as Charge Stripper Complement	836
SPWR037	use link to see paper's listing under its alternate paper code
	A. Lajoie NSCL, East Lansing, Michigan, USA A. Hershcovitch, P. Thieberger BNL, Upton, Long Island, New York, USA F. Marti FRIB, East Lansing, USA
	Funding: NSF Cooperative Agreement, Award No. PHY-1102511 Modern ion accelerators, particularly heavy ion accelerators, almost universally make use of charge stripping. A challenge facing facilities, as the demand for higher intensity beams rises, is a stripping media that's highly resistant to degradation, such as a recirculating He gas stripper. A method of keeping the He gas localized in a segment along the beamline by means of a Plasma Window (PW) positioned on both sides of the gas stripper has been proposed and the initial design set forth by Ady Hershcovitch. With a cascaded plasma arc being the interface between high pressure stripper and low pressure beamline, the goal is to minimize gas flowrate from the stripper to the beamline in order to maintain sufficient isolation of the He gas. We present the initial results from the test stand developed at Michigan State University and the planned experimental program that will follow.
	Poster THPRC030 [0.626 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPRC030
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRC031	Manufacturing of MEBT Combined Quadrupole & Steerer Magnets for the Linear IFMIF Prototype Accelerator LIPAC	840
	J. Castellanos, B. Brañas, J. Mollá, C. Oliver, I. Podadera, F. Toral CIEMAT, Madrid, Spain R. Iturbe, B. López ANTEC Magnets SLU, Vizcaya, Spain O. Nomen IREC, Sant Adria del Besos, Spain
	Funding: This work has been funded by the Spanish Ministry of Economy and Competitiveness under the Agreement as published in BOE, 16/01/2013, page 1988. The Medium Energy Beam Transport line (MEBT) that is being installed on the LIPAC accelerator* will have five quadrupole and steerer magnets which have been recently manufactured and tested. The design of the magnets was done by CIEMAT** and considers a magnetic yoke made of four solid iron quadrants joined together. The yoke integrates four water-cooled coils (quadrupole) and eight air-cooled coils (steerers) made of copper wires. The manufacturing and testing (excluded magnetic measurements) of the five magnets were carried out by the Spanish company ANTECSA. This paper focuses on the technical aspects considered during the manufacturing and the assembly of the different components of the magnets. The details about the geometrical, electrical and hydraulic measurements and tests that were carried out before the magnetic measurements are also described. * A. Mosnier et al., IPAC10, MOPEC056, p.588, Kyoto, Japan (2010) ** C. Oliver et al., IPAC11, WEPO014, p. 2424, San Sebastián, Spain (2011)
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPRC031
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THPRC032	Towards User Defined Web Applications in Accelerator Labs	843
	D. Liu FRIB, East Lansing, USA
	Most Web application users in accelerator labs understand the basics of data types and data structures. They have in-depth knowledge about accelerator physics and other engineering domains. Some even develop software applications by themselves. In the approach of user-defined web applications, a user defines her/his own web application, test and use it first before sharing it to other users. It saves the communication efforts between developers and users, reduces the time from application design to production. Most importantly, users become the owner of the application and naturally the owner of the data that the application collects and produces. This will largely improve an application's quality and user experience. At FRIB, we have been practicing this approach. One of our applications, the traveler, has been developed and operated for about three years, and used by users from various departments including cryomodule, electrical engineering, controls, and business development. The traveler application allows users to design their data collection interface in a what-you-see-is-what-you-get way, and to release it by sharing with other users and groups in the lab. We are now designing and developing a generic data store that will enable users to define their own data structure, to track structure and instance value changes, and to control the access to the data. This material is based upon work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661, the State of Michigan and Michigan State University.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPRC032
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THPLR019	A Laser Pulse Controller for the Injector Laser at FLASH and European XFEL	882
	C. Grün, S. Schreiber, T. Schulz DESY, Hamburg, Germany
	FLASH is a multi-beamline free-electron laser user facility which provides femtosecond long high brilliant photon pulses in the extreme-UV and soft-X ray wavelength range. One pulsed superconducting linac accelerates electron bunches for two undulator beamlines, while a third beamline is under construction. Within each RF-pulse, trains of hundreds of electron bunches are produced in a photo-cathode RF gun, accelerated in the linac and distributed by fast kickers into the undulator beamlines. In order to fulfill the parameter ranges of the multiple user experiments each bunch train can be tuned individually in bunch number from 0 - 800, spacing from 1 μs - 25 μs and intensity from 0.1 nC - 1 nC. To make this possible, three injector laser systems are used and this allows FLASH to vary independently the laser settings for the designated undulator beamlines. A laser controller has been developed to make a multi-users operation mode possible. The controller uses a Field Programmable Gate Array (FPGA) to control the time structure of the laser pulses and it provides the interface for the timing and the machine protection system. The controller has been implemented using the MicroTCA.4 technology. The controller was ported to the injector laser system at the European XFEL facility and is in operation since end 2015.
	Poster THPLR019 [1.967 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPLR020	Status and Progress of FRIB High Level Controls	885
	G. Shen, E.T. Berryman, D. Chabot, M.A. Davidsaver, K. Fukushima, Z.Q. He, M. Ikegami, M.G. Konrad, D. Liu, D.G. Maxwell, V. Vuppala FRIB, East Lansing, USA
	Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661 FRIB, which is a new heavy ion accelerator facility to provide intense beams of rare isotopes, is currently under construction at Michigan State University. Its driver linac accelerates all stable ions up to uranium, and targets to provides a CW beam with the energy of 200 MeV/u and the beam power of 400 kW. The beam commissioning of the its Front-End has been planned to start from Middle of 2016. The high level controls for incoming commissioning is under active development and deployment. The latest status progress will be presented in this paper.
	Poster THPLR020 [2.291 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR020
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPLR021	Identification of Emitting Sources of Dark Currents From Gridded Thermionic Electron Gun and Measures to Suppress Dark Currents From Electron Gun in SPring-8 Linear Accelerator	888
	T. Magome, H. Hanaki, T. Kobayashi, S. Suzuki, T. Taniuchi JASRI/SPring-8, Hyogo-ken, Japan
	The dark current is emitted from a gridded thermionic electron gun although the grid-electrode potential against the cathode is negative enough to suppress the cathode emission current. This dark current in the SPring-8 linear accelerator caused satellite bunches unignorable for precise experiments in the downstream electron storage ring. The dark current has been investigated by means of our electron-gun test equipment applying a DC accelerator voltage to the electron gun. The investigations revealed that the dark current was generated from the wehnelt electrode, the gird electrode, and the cathode surface. The dark current from the wehnelt electrode was decreased under the measurement limit 2·10^-15 A by replacing the wehnelt and the anode electrodes with new electro-polished ones. The dark current from the cathode surface was reduced by lowering the grid-electrode potential against the cathode down to -160 V. To reduce the dark current from the grid electrode, the surface of the grid electrode was significantly smoothed by electro-polishing.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

THPRC029

Comissioning Results for a Subharmonic Buncher at REA

833

SPWR035

use link to see paper's listing under its alternate paper code

D.M. Alt, J.F. Brandon, S.W. Krause, A. Lapierre, D.G. Morris, S. Nash, N.R. Usher, A.C.C. Villari, S.J. Williams, S. Zhao
FRIB, East Lansing, USA
M.J. Syphers
Northern Illinois University, DeKalb, Illinois, USA

Funding: NSF PHY-1102511
The reaccelerator facility (ReA) at the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University (MSU) offers a unique capability to study reactions with low-energy beams of rare isotopes. A beam from the coupled cyclotron facility is stopped in a gas stopping system, charge bred in an Electron Beam Ion Trap (EBIT), and then reaccelerated in a compact superconducting LINAC. The original beam repetition rate at the ReA targets was the same as the LINAC RF frequency of 80.5 MHz. In order to add the capability to bunch at a lower frequency (desirable for many types of experiments using time of flight data acquisitions) a 16.1 MHz buncher has been designed, constructed, and commissioned. This paper reports the results of the commissioning of the device, and outlines some future avenues for further improvement of the properties of the bunched beam.

Poster THPRC029 [0.903 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPRC029

Export •

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

THPRC030

Plasma Window as Charge Stripper Complement

836

SPWR037

use link to see paper's listing under its alternate paper code

A. Lajoie
NSCL, East Lansing, Michigan, USA
A. Hershcovitch, P. Thieberger
BNL, Upton, Long Island, New York, USA
F. Marti
FRIB, East Lansing, USA

Funding: NSF Cooperative Agreement, Award No. PHY-1102511
Modern ion accelerators, particularly heavy ion accelerators, almost universally make use of charge stripping. A challenge facing facilities, as the demand for higher intensity beams rises, is a stripping media that's highly resistant to degradation, such as a recirculating He gas stripper. A method of keeping the He gas localized in a segment along the beamline by means of a Plasma Window (PW) positioned on both sides of the gas stripper has been proposed and the initial design set forth by Ady Hershcovitch. With a cascaded plasma arc being the interface between high pressure stripper and low pressure beamline, the goal is to minimize gas flowrate from the stripper to the beamline in order to maintain sufficient isolation of the He gas. We present the initial results from the test stand developed at Michigan State University and the planned experimental program that will follow.

Poster THPRC030 [0.626 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPRC030

Export •

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

THPRC031

Manufacturing of MEBT Combined Quadrupole & Steerer Magnets for the Linear IFMIF Prototype Accelerator LIPAC

840

J. Castellanos, B. Brañas, J. Mollá, C. Oliver, I. Podadera, F. Toral
CIEMAT, Madrid, Spain
R. Iturbe, B. López
ANTEC Magnets SLU, Vizcaya, Spain
O. Nomen
IREC, Sant Adria del Besos, Spain

Funding: This work has been funded by the Spanish Ministry of Economy and Competitiveness under the Agreement as published in BOE, 16/01/2013, page 1988.
The Medium Energy Beam Transport line (MEBT) that is being installed on the LIPAC accelerator* will have five quadrupole and steerer magnets which have been recently manufactured and tested. The design of the magnets was done by CIEMAT** and considers a magnetic yoke made of four solid iron quadrants joined together. The yoke integrates four water-cooled coils (quadrupole) and eight air-cooled coils (steerers) made of copper wires. The manufacturing and testing (excluded magnetic measurements) of the five magnets were carried out by the Spanish company ANTECSA. This paper focuses on the technical aspects considered during the manufacturing and the assembly of the different components of the magnets. The details about the geometrical, electrical and hydraulic measurements and tests that were carried out before the magnetic measurements are also described.
* A. Mosnier et al., IPAC10, MOPEC056, p.588, Kyoto, Japan (2010)
** C. Oliver et al., IPAC11, WEPO014, p. 2424, San Sebastián, Spain (2011)

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPRC031

Export •

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

THPRC032

Towards User Defined Web Applications in Accelerator Labs

843

D. Liu
FRIB, East Lansing, USA

Most Web application users in accelerator labs understand the basics of data types and data structures. They have in-depth knowledge about accelerator physics and other engineering domains. Some even develop software applications by themselves. In the approach of user-defined web applications, a user defines her/his own web application, test and use it first before sharing it to other users. It saves the communication efforts between developers and users, reduces the time from application design to production. Most importantly, users become the owner of the application and naturally the owner of the data that the application collects and produces. This will largely improve an application's quality and user experience. At FRIB, we have been practicing this approach. One of our applications, the traveler, has been developed and operated for about three years, and used by users from various departments including cryomodule, electrical engineering, controls, and business development. The traveler application allows users to design their data collection interface in a what-you-see-is-what-you-get way, and to release it by sharing with other users and groups in the lab. We are now designing and developing a generic data store that will enable users to define their own data structure, to track structure and instance value changes, and to control the access to the data.
This material is based upon work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661, the State of Michigan and Michigan State University.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPRC032

Export •

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

THPLR019

A Laser Pulse Controller for the Injector Laser at FLASH and European XFEL

882

C. Grün, S. Schreiber, T. Schulz
DESY, Hamburg, Germany

FLASH is a multi-beamline free-electron laser user facility which provides femtosecond long high brilliant photon pulses in the extreme-UV and soft-X ray wavelength range. One pulsed superconducting linac accelerates electron bunches for two undulator beamlines, while a third beamline is under construction. Within each RF-pulse, trains of hundreds of electron bunches are produced in a photo-cathode RF gun, accelerated in the linac and distributed by fast kickers into the undulator beamlines. In order to fulfill the parameter ranges of the multiple user experiments each bunch train can be tuned individually in bunch number from 0 - 800, spacing from 1 μs - 25 μs and intensity from 0.1 nC - 1 nC. To make this possible, three injector laser systems are used and this allows FLASH to vary independently the laser settings for the designated undulator beamlines. A laser controller has been developed to make a multi-users operation mode possible. The controller uses a Field Programmable Gate Array (FPGA) to control the time structure of the laser pulses and it provides the interface for the timing and the machine protection system. The controller has been implemented using the MicroTCA.4 technology. The controller was ported to the injector laser system at the European XFEL facility and is in operation since end 2015.

Poster THPLR019 [1.967 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR019

Export •

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

THPLR020

Status and Progress of FRIB High Level Controls

885

G. Shen, E.T. Berryman, D. Chabot, M.A. Davidsaver, K. Fukushima, Z.Q. He, M. Ikegami, M.G. Konrad, D. Liu, D.G. Maxwell, V. Vuppala
FRIB, East Lansing, USA

Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661
FRIB, which is a new heavy ion accelerator facility to provide intense beams of rare isotopes, is currently under construction at Michigan State University. Its driver linac accelerates all stable ions up to uranium, and targets to provides a CW beam with the energy of 200 MeV/u and the beam power of 400 kW. The beam commissioning of the its Front-End has been planned to start from Middle of 2016. The high level controls for incoming commissioning is under active development and deployment. The latest status progress will be presented in this paper.

Poster THPLR020 [2.291 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR020

Export •

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

THPLR021

Identification of Emitting Sources of Dark Currents From Gridded Thermionic Electron Gun and Measures to Suppress Dark Currents From Electron Gun in SPring-8 Linear Accelerator

888

T. Magome, H. Hanaki, T. Kobayashi, S. Suzuki, T. Taniuchi
JASRI/SPring-8, Hyogo-ken, Japan

The dark current is emitted from a gridded thermionic electron gun although the grid-electrode potential against the cathode is negative enough to suppress the cathode emission current. This dark current in the SPring-8 linear accelerator caused satellite bunches unignorable for precise experiments in the downstream electron storage ring. The dark current has been investigated by means of our electron-gun test equipment applying a DC accelerator voltage to the electron gun. The investigations revealed that the dark current was generated from the wehnelt electrode, the gird electrode, and the cathode surface. The dark current from the wehnelt electrode was decreased under the measurement limit 2·10^-15 A by replacing the wehnelt and the anode electrodes with new electro-polished ones. The dark current from the cathode surface was reduced by lowering the grid-electrode potential against the cathode down to -160 V. To reduce the dark current from the grid electrode, the surface of the grid electrode was significantly smoothed by electro-polishing.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR021

Export •

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