LINAC2014 - List of Authors (Saini, A.)

Paper	Title	Page
MOPP050	Transmission Efficiency Measurement at the FNAL 4-rod RFQ	168
	J.-P. Carneiro, F.G. Garcia, J.-F. Ostiguy, A. Saini, R.M. Zwaska Fermilab, Batavia, Illinois, USA B. Mustapha, P.N. Ostroumov ANL, Argonne, Illinois, USA
	This paper presents measurements of the beam transmission performed on the 4-rods RFQ currently under operation at Fermilab. The beam current has been measured at the RFQ exit as a function of the magnetic field strength in the 2 LEBT solenoids. This measurement is compared with a scan performed on the Fermi Grid with the beam dynamics code TRACK. A particular attention is given to the impact, on the RFQ beam transmission, of the space-charge neutralization in the LEBT and of the field asymmetry on the 4-rods RFQ.

MOPP126	Untrapped HOM Radiation Absorption in the LCLS-II Cryomodules	351
	K.L.F. Bane, C. Adolphsen, C.D. Nantista, T.O. Raubenheimer SLAC, Menlo Park, California, USA A. Saini, N. Solyak, V.P. Yakovlev Fermilab, Batavia, Illinois, USA
	Funding: Work supported by Department of Energy contract DE–AC02–76SF00515. The superconducting cavities in the continuous wave (CW) linacs of LCLS-II are designed to operate at 2 K, where cooling costs are very expensive. One source of heat is presented by the higher order mode (HOM) power deposited by the beam. Due to the very short bunch length-especially in L3 the final linac-the LCLS-II beam spectrum extends into the terahertz range. Ceramic absorbers, at 70 K and located between cryomodules, are meant to absorb much of this power. In this report we perform two kinds of calculations to estimate the effectiveness of the absorbers and the amount of beam power that needs to be removed at 2 K.

TUPP054	Study of Beam-Based Alignment for the LCLS-II SC Linac	544
	A. Saini, N. Solyak, V.P. Yakovlev Fermilab, Batavia, Illinois, USA T.O. Raubenheimer SLAC, Menlo Park, California, USA
	The Linac Coherent Light Source (LCLS) is an x-ray free electron laser facility. The proposed upgrade of the LCLS facility is based on construction of 4 GeV superconducting (SC) linac. The achievable performance of linac is determined by beam sensitivity to various component errors. In this paper we review misalignment tolerances of LCLS-II SC linac and discuss possible beam-based alignment algorithm to meet these tolerances.

THPP054	Study of Coupler's Effect in Third Harmonic Section of LCLS-II SC Linac	969
	A. Saini, A. Lunin, N. Solyak, V.P. Yakovlev Fermilab, Batavia, Illinois, USA T.O. Raubenheimer SLAC, Menlo Park, California, USA
	The Linac Coherent Light Source (LCLS) is an x-ray free electron laser facility. The proposed upgrade of the LCLS facility is based on construction of 4 GeV superconducting (SC) linac which will use two stage bunch compression scheme in order to achieve short bunches with high peak current. In order to reduce non-linear effects in first bunch compressor, third harmonic section is utilized to linearize longitudinal phase space of the beam. However, transverse phase space of beam may get distorted due to coupler RF kicks and coupler wake kicks resulting from the asymmetry of input and HOM couplers in 3.9 GHz cavity. In this paper, we discuss coupler's effects and estimate resulting emittance dilution in third harmonic section. Local compensation of coupler kicks using different orientation of cavities are also addressed.

THPP060	Effect of Cavity Couplers Field on the Beam Dynamics of the LCLS-II Injector	989
	A. Vivoli, A. Lunin, A. Saini, N. Solyak Fermilab, Batavia, Illinois, USA A.C. Bartnik, I.V. Bazarov, B.M. Dunham, C.M. Gulliford, C.E. Mayes Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA D. Dowell, Z. Li, T.O. Raubenheimer, J.F. Schmerge, T. Vecchione, F. Zhou SLAC, Menlo Park, California, USA D. Filippetto, R. Huang, C. F. Papadopoulos, H.J. Qian, S.P. Virostek, R.P. Wells LBNL, Berkeley, California, USA
	LCLS-II is a new light source based on a continuous wave (cw) superconducting linac to be built at SLAC. The Injector section of the linac creates the elecron beam and accelerates it up to about 100 MeV. The couplers of the accelerating cavities produce an asymmetric field resulting in a beam offset and, most importantly, in a significant transverse emittance dilution, if not compensated. In this paper we describe the simulations of the LCLS-II injector taking into account the cavity couplers effect and some mitigation techniques to reduce its impact on the beam quality.

Paper

Title

Page

Transmission Efficiency Measurement at the FNAL 4-rod RFQ

168

J.-P. Carneiro, F.G. Garcia, J.-F. Ostiguy, A. Saini, R.M. Zwaska
Fermilab, Batavia, Illinois, USA
B. Mustapha, P.N. Ostroumov
ANL, Argonne, Illinois, USA

This paper presents measurements of the beam transmission performed on the 4-rods RFQ currently under operation at Fermilab. The beam current has been measured at the RFQ exit as a function of the magnetic field strength in the 2 LEBT solenoids. This measurement is compared with a scan performed on the Fermi Grid with the beam dynamics code TRACK. A particular attention is given to the impact, on the RFQ beam transmission, of the space-charge neutralization in the LEBT and of the field asymmetry on the 4-rods RFQ.

MOPP126

Untrapped HOM Radiation Absorption in the LCLS-II Cryomodules

351

K.L.F. Bane, C. Adolphsen, C.D. Nantista, T.O. Raubenheimer
SLAC, Menlo Park, California, USA
A. Saini, N. Solyak, V.P. Yakovlev
Fermilab, Batavia, Illinois, USA

Funding: Work supported by Department of Energy contract DE–AC02–76SF00515.
The superconducting cavities in the continuous wave (CW) linacs of LCLS-II are designed to operate at 2 K, where cooling costs are very expensive. One source of heat is presented by the higher order mode (HOM) power deposited by the beam. Due to the very short bunch length-especially in L3 the final linac-the LCLS-II beam spectrum extends into the terahertz range. Ceramic absorbers, at 70 K and located between cryomodules, are meant to absorb much of this power. In this report we perform two kinds of calculations to estimate the effectiveness of the absorbers and the amount of beam power that needs to be removed at 2 K.

TUPP054

Study of Beam-Based Alignment for the LCLS-II SC Linac

544

A. Saini, N. Solyak, V.P. Yakovlev
Fermilab, Batavia, Illinois, USA
T.O. Raubenheimer
SLAC, Menlo Park, California, USA

The Linac Coherent Light Source (LCLS) is an x-ray free electron laser facility. The proposed upgrade of the LCLS facility is based on construction of 4 GeV superconducting (SC) linac. The achievable performance of linac is determined by beam sensitivity to various component errors. In this paper we review misalignment tolerances of LCLS-II SC linac and discuss possible beam-based alignment algorithm to meet these tolerances.

THPP054

Study of Coupler's Effect in Third Harmonic Section of LCLS-II SC Linac

969

A. Saini, A. Lunin, N. Solyak, V.P. Yakovlev
Fermilab, Batavia, Illinois, USA
T.O. Raubenheimer
SLAC, Menlo Park, California, USA

The Linac Coherent Light Source (LCLS) is an x-ray free electron laser facility. The proposed upgrade of the LCLS facility is based on construction of 4 GeV superconducting (SC) linac which will use two stage bunch compression scheme in order to achieve short bunches with high peak current. In order to reduce non-linear effects in first bunch compressor, third harmonic section is utilized to linearize longitudinal phase space of the beam. However, transverse phase space of beam may get distorted due to coupler RF kicks and coupler wake kicks resulting from the asymmetry of input and HOM couplers in 3.9 GHz cavity. In this paper, we discuss coupler's effects and estimate resulting emittance dilution in third harmonic section. Local compensation of coupler kicks using different orientation of cavities are also addressed.

THPP060

Effect of Cavity Couplers Field on the Beam Dynamics of the LCLS-II Injector

989

A. Vivoli, A. Lunin, A. Saini, N. Solyak
Fermilab, Batavia, Illinois, USA
A.C. Bartnik, I.V. Bazarov, B.M. Dunham, C.M. Gulliford, C.E. Mayes
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
D. Dowell, Z. Li, T.O. Raubenheimer, J.F. Schmerge, T. Vecchione, F. Zhou
SLAC, Menlo Park, California, USA
D. Filippetto, R. Huang, C. F. Papadopoulos, H.J. Qian, S.P. Virostek, R.P. Wells
LBNL, Berkeley, California, USA

LCLS-II is a new light source based on a continuous wave (cw) superconducting linac to be built at SLAC. The Injector section of the linac creates the elecron beam and accelerates it up to about 100 MeV. The couplers of the accelerating cavities produce an asymmetric field resulting in a beam offset and, most importantly, in a significant transverse emittance dilution, if not compensated. In this paper we describe the simulations of the LCLS-II injector taking into account the cavity couplers effect and some mitigation techniques to reduce its impact on the beam quality.