LINAC2014 - List of Authors (Baffes, C.M.)

Paper	Title	Page
MOPP058	Z-slicer: A Simple Scheme for Electron Beam Current Profile Shaping in a Linac	183
	J.C.T. Thangaraj, C.M. Baffes, D.R. Broemmelsiek, D.J. Crawford, R.M. Thurman-Keup Fermilab, Batavia, Illinois, USA W.B. Wortley University of Rochester, Rochester, New York, USA
	Short bunches are a premium at accelerator facilities and their applications include THz generation, short bunch production, shaped bunch production, etc. In this work we report on the design of an experiment involving an electron beam about 50 MeV that will be intercepted by a set of metallic slits inside a bunch compressor. After the mask, some electrons are scattered while other pass through un-affected. After exiting the bunch compressor, those electrons that were not affected by the slits will appear as short electron bunches. The key advantage of our scheme is its simplicity, tunability and low cost. The scheme does not require any additional hardware such as lasers, undulator, transverse deflecting cavity. The tuning variable is only the RF-chirp and detection of the bunching requires just a skew quad in the chicane and a transverse screen downstream. A thermal analysis suggests that MHz operation of the linac can be sustained under certain beam conditions without any damage to the slit mask.

THPP055	High Power Density Test of PXIE MEBT Absorber Prototype	973
	A.V. Shemyakin, C.M. Baffes Fermilab, Batavia, Illinois, USA
	Funding: Fermilab is operated by Fermi Research Alliance, LLC, under Contract DE-AC02-07CH11359 with the United States Department of Energy One of the goals of the PXIE program at Fermilab is to demonstrate the capability to form an arbitrary bunch pattern from an initially CW 162.5 MHz H⁻ bunch train coming out of an RFQ. The bunch-by-bunch selection will take place in the 2.1 MeV Medium Energy Beam Transport (MEBT) by directing the undesired bunches onto an absorber that needs to withstand a beam power of up to 21 kW, focused onto a spot with a ~2 mm rms radius. Two prototypes of the absorber were manufactured from molybdenum alloy TZM, and tested with a 28 keV DC electron beam up to the peak surface power density required for PXIE, 17W/mm2. Temperatures and flow parameters were measured and compared to analysis. This paper describes the absorber prototypes and key testing results.

THPP056	Status of the Warm Front End of PXIE	976
	A.V. Shemyakin, M.L. Alvarez, R. Andrews, C.M. Baffes, A.Z. Chen, R.T.P. D'Arcy, B.M. Hanna, L.R. Prost, G.W. Saewert, V.E. Scarpine, J. Steimel, D. Sun Fermilab, Batavia, Illinois, USA R.T.P. D'Arcy UCL, London, United Kingdom D. Li LBNL, Berkeley, California, USA
	Funding: Fermilab is operated by Fermi Research Alliance, LLC, under Contract DE-AC02-07CH11359 with the United States Department of Energy A CW-compatible, pulsed H⁻ superconducting linac is envisaged as a possible path for upgrading Fermilab’s injection complex. To validate the concept of the front-end of such machine, a test accelerator (a.k.a. PXIE) is under construction. The warm part of this accelerator comprises a 10 mA DC, 30 keV H⁻ ion source, a 2m-long LEBT, a 2.1 MeV CW RFQ, and a 10-m long MEBT that is capable of creating a large variety of bunch structures. The paper will report commissioning results of a partially assembled LEBT, status of RFQ manufacturing, and describe development of the MEBT, in particular, of elements of its chopping system.

Paper

Title

Page

Z-slicer: A Simple Scheme for Electron Beam Current Profile Shaping in a Linac

183

J.C.T. Thangaraj, C.M. Baffes, D.R. Broemmelsiek, D.J. Crawford, R.M. Thurman-Keup
Fermilab, Batavia, Illinois, USA
W.B. Wortley
University of Rochester, Rochester, New York, USA

Short bunches are a premium at accelerator facilities and their applications include THz generation, short bunch production, shaped bunch production, etc. In this work we report on the design of an experiment involving an electron beam about 50 MeV that will be intercepted by a set of metallic slits inside a bunch compressor. After the mask, some electrons are scattered while other pass through un-affected. After exiting the bunch compressor, those electrons that were not affected by the slits will appear as short electron bunches. The key advantage of our scheme is its simplicity, tunability and low cost. The scheme does not require any additional hardware such as lasers, undulator, transverse deflecting cavity. The tuning variable is only the RF-chirp and detection of the bunching requires just a skew quad in the chicane and a transverse screen downstream. A thermal analysis suggests that MHz operation of the linac can be sustained under certain beam conditions without any damage to the slit mask.

THPP055

High Power Density Test of PXIE MEBT Absorber Prototype

973

A.V. Shemyakin, C.M. Baffes
Fermilab, Batavia, Illinois, USA

Funding: Fermilab is operated by Fermi Research Alliance, LLC, under Contract DE-AC02-07CH11359 with the United States Department of Energy
One of the goals of the PXIE program at Fermilab is to demonstrate the capability to form an arbitrary bunch pattern from an initially CW 162.5 MHz H⁻ bunch train coming out of an RFQ. The bunch-by-bunch selection will take place in the 2.1 MeV Medium Energy Beam Transport (MEBT) by directing the undesired bunches onto an absorber that needs to withstand a beam power of up to 21 kW, focused onto a spot with a ~2 mm rms radius. Two prototypes of the absorber were manufactured from molybdenum alloy TZM, and tested with a 28 keV DC electron beam up to the peak surface power density required for PXIE, 17W/mm2. Temperatures and flow parameters were measured and compared to analysis. This paper describes the absorber prototypes and key testing results.

THPP056

Status of the Warm Front End of PXIE

976

A.V. Shemyakin, M.L. Alvarez, R. Andrews, C.M. Baffes, A.Z. Chen, R.T.P. D'Arcy, B.M. Hanna, L.R. Prost, G.W. Saewert, V.E. Scarpine, J. Steimel, D. Sun
Fermilab, Batavia, Illinois, USA
R.T.P. D'Arcy
UCL, London, United Kingdom
D. Li
LBNL, Berkeley, California, USA

Funding: Fermilab is operated by Fermi Research Alliance, LLC, under Contract DE-AC02-07CH11359 with the United States Department of Energy
A CW-compatible, pulsed H⁻ superconducting linac is envisaged as a possible path for upgrading Fermilab’s injection complex. To validate the concept of the front-end of such machine, a test accelerator (a.k.a. PXIE) is under construction. The warm part of this accelerator comprises a 10 mA DC, 30 keV H⁻ ion source, a 2m-long LEBT, a 2.1 MeV CW RFQ, and a 10-m long MEBT that is capable of creating a large variety of bunch structures. The paper will report commissioning results of a partially assembled LEBT, status of RFQ manufacturing, and describe development of the MEBT, in particular, of elements of its chopping system.