ERL2019 - List of Authors (Banerjee, N.)

Paper	Title	Page
TUCOXBS05	Beam Timing and Cavity Phasing	39
	R.M. Koscica, N. Banerjee, G.H. Hoffstaetter, W. Lou, G.T. Premawardhana Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	In a multi-pass Energy Recovery Linac (ERL), each cavity must regain all energy expended from beam acceleration during beam deceleration. The beam should also achieve specific energy targets during each loop that returns it to the linac. To satisfy the energy recovery and loop requirements, one must specify the phase and voltage of cavity fields, and one must control the beam flight times through the return loops. Adequate values for these parameters can be found by using a full scale numerical optimization program. If symmetry is imposed in beam time and energy during acceleration and deceleration, the number of parameters needed decreases, simplifying the optimization. As an example, symmetric models of the Cornell BNL ERL Test Accelerator (CBETA) are considered. Energy recovery results from recent CBETA single-turn tests are presented, as well as multi-turn solutions that satisfy CBETA optimization targets of loop energy and zero cavity loading.
	Slides TUCOXBS05 [5.186 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-ERL2019-TUCOXBS05
About •	paper received ※ 13 September 2019 paper accepted ※ 01 November 2019 issue date ※ 24 June 2020
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THCOWBS07	Passive and Active Control of Microphonics at CBETA and Elsewhere
	N. Banerjee, G.H. Hoffstaetter, M. Liepe, P. Quigley Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Funding: This work was performed through the support of New York State Energy Research and Development Agency (NYSERDA). Superconducting Radio Frequency (SRF) cavities operating with large loaded quality factors is the natural choice for Energy Recovery Linacs which operate at negligible beam loading. While this leads to lower RF power requirements, the stability of the accelerating field is strongly influenced by peak microphonics detuning. In this talk, I will discuss various methods of passively suppressing vibrations used in various facilities using low bandwidth SRF systems, with special reference to CBETA, a multi-turn SRF ERL being commissioned at Cornell University. I will also describe our active microphonics control system based on a modified narrow band Active Noise Control (ANC) algorithm and compare it with schemes being explored in other machines.
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FRCOWBS04	Essential Instrumentation for the Characterization of ERL Beams	150
	N. Banerjee, A.C. Bartnik, K.E. Deitrick, J. Dobbins, C.M. Gulliford, G.H. Hoffstaetter Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA J.S. Berg, S.J. Brooks, R.J. Michnoff BNL, Upton, New York, USA
	Funding: This work was performed through the support of New York State Energy Research and Development Agency (NYSERDA). The typical requirement of Energy Recovery Linacs to produce beams with high repetition rate and high bunch charge presents unique demands on beam diagnostics. ERLs being quite sensitive to time of flight effects necessitate the use of beam arrival time monitors along with typical position detection. Being subjected to a plethora of dynamic effects, both longitudinal and transverse phase space monitoring of the beam becomes quite important. Additionally, beam halo plays an important role determining the overall transmission. Consequently, we also need to characterize halo both directly using sophisticated beam viewers and indirectly using radiation monitors. In this talk, I will describe the instrumentation essential to ERL operation using the Cornell-BNL ERL Test Accelerator (CBETA) as a pertinent example.
	Slides FRCOWBS04 [7.129 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-ERL2019-FRCOWBS04
About •	paper received ※ 19 September 2019 paper accepted ※ 01 November 2019 issue date ※ 24 June 2020
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Beam Timing and Cavity Phasing

39

R.M. Koscica, N. Banerjee, G.H. Hoffstaetter, W. Lou, G.T. Premawardhana
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

In a multi-pass Energy Recovery Linac (ERL), each cavity must regain all energy expended from beam acceleration during beam deceleration. The beam should also achieve specific energy targets during each loop that returns it to the linac. To satisfy the energy recovery and loop requirements, one must specify the phase and voltage of cavity fields, and one must control the beam flight times through the return loops. Adequate values for these parameters can be found by using a full scale numerical optimization program. If symmetry is imposed in beam time and energy during acceleration and deceleration, the number of parameters needed decreases, simplifying the optimization. As an example, symmetric models of the Cornell BNL ERL Test Accelerator (CBETA) are considered. Energy recovery results from recent CBETA single-turn tests are presented, as well as multi-turn solutions that satisfy CBETA optimization targets of loop energy and zero cavity loading.

Slides TUCOXBS05 [5.186 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-ERL2019-TUCOXBS05

About •

paper received ※ 13 September 2019 paper accepted ※ 01 November 2019 issue date ※ 24 June 2020

Export •

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

THCOWBS07

Passive and Active Control of Microphonics at CBETA and Elsewhere

N. Banerjee, G.H. Hoffstaetter, M. Liepe, P. Quigley
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: This work was performed through the support of New York State Energy Research and Development Agency (NYSERDA).
Superconducting Radio Frequency (SRF) cavities operating with large loaded quality factors is the natural choice for Energy Recovery Linacs which operate at negligible beam loading. While this leads to lower RF power requirements, the stability of the accelerating field is strongly influenced by peak microphonics detuning. In this talk, I will discuss various methods of passively suppressing vibrations used in various facilities using low bandwidth SRF systems, with special reference to CBETA, a multi-turn SRF ERL being commissioned at Cornell University. I will also describe our active microphonics control system based on a modified narrow band Active Noise Control (ANC) algorithm and compare it with schemes being explored in other machines.

Export •

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

FRCOWBS04

Essential Instrumentation for the Characterization of ERL Beams

150

N. Banerjee, A.C. Bartnik, K.E. Deitrick, J. Dobbins, C.M. Gulliford, G.H. Hoffstaetter
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
J.S. Berg, S.J. Brooks, R.J. Michnoff
BNL, Upton, New York, USA

Funding: This work was performed through the support of New York State Energy Research and Development Agency (NYSERDA).
The typical requirement of Energy Recovery Linacs to produce beams with high repetition rate and high bunch charge presents unique demands on beam diagnostics. ERLs being quite sensitive to time of flight effects necessitate the use of beam arrival time monitors along with typical position detection. Being subjected to a plethora of dynamic effects, both longitudinal and transverse phase space monitoring of the beam becomes quite important. Additionally, beam halo plays an important role determining the overall transmission. Consequently, we also need to characterize halo both directly using sophisticated beam viewers and indirectly using radiation monitors. In this talk, I will describe the instrumentation essential to ERL operation using the Cornell-BNL ERL Test Accelerator (CBETA) as a pertinent example.

Slides FRCOWBS04 [7.129 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-ERL2019-FRCOWBS04

About •

paper received ※ 19 September 2019 paper accepted ※ 01 November 2019 issue date ※ 24 June 2020

Export •

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