Development of Transverse Modes Damped DLA Structure* C. Jing, P. Schoessow, A. Kanareykin, Euclid...
-
Upload
emery-tucker -
Category
Documents
-
view
215 -
download
0
Transcript of Development of Transverse Modes Damped DLA Structure* C. Jing, P. Schoessow, A. Kanareykin, Euclid...
Development of Transverse Modes Damped DLA Structure*
C. Jing, P. Schoessow, A. Kanareykin, Euclid Techlabs, LLC
R. Konecny, W. Gai, J. Power, W. Liu, HEP, ANL
AAC08, July. 27th---Aug.2nd , 2008 * work is supported by DoE SBIR Phase I funding.
2
Outline
• Introduction
• Structure Design
• Planned Experiment
• Summary
3
Introduction
4
Transverse mode in DLA structure
10.18GHz11.424GHz
TM01 mode Ez HEM11 mode Ez
Conventional Quartz DLA
5
Surface current distributions for different modes
Surface current
TM01 mode (axial current only)
HEM11 mode (azimuthal current included)
6
Previous work by AWA fellows*
* E. Chojnacki, W. Gai, C. Ho, R. Konecny, S. Mtingwa, J. Norem , M. Rosing, P. Schoessow, and J. Simpson, J. Appl. Phys. 69 (9), 1 May 1991.
Insulated conductor wires
Dielectric tube
Longitudinal Wake
Transverse Wake
7
New Design to Heavily Damp Hybrid Modes in DLA Structure
8
Design of transverse mode damping structure
Hybrid mode damping DLA
SiC(εr ~13; tanδ ~0.22 @ 11GHz)CopperDielectricsVacuum
9
Simulations
E_TM01(0,1mm,z)
E_HEM11(0,1mm,z)
E field (TM01 mode)
E-field (HEM11 mode)
0
1000
2000
3000
4000
5000
6000
7000
8000
0 50 100 150 200
Length (mm)
E_a
mpl
itude
(V/m
)
Conventional DLA
Transverse Moded Damped DLA
0
100
200
300
400
500
600
700
0 50 100 150 200
Length (mm)
E_a
mpl
itude
(V/m
)
Conventional DLA
Transverse mode damped DLA
10
Simulated parameters
*In the desired frequency band, SiC (εr = 13; tanδ = 0.22) and quartz (εr =3.78; tanδ= 0.5×104) are used in the calculations. ; Slots / circumference = 22%.
Comparison of the 7.8GHz Conventional and the Transverse mode Damped DLA structure.
Freq. Q in conventional DLA structure
Q in transverse modes damped DLA structure
Accelerating mode (TM01)
7.8GHz 6964* 6738*
Transverse modes (HEM11)
6.34GHz 6866* 23*
11
The longitudinal (red curve) and transverse (blue curve) wakefields and their spectrums in the 7.8GHz conventional DLA structure. Beam (black curve) parameters used in the calculation are: 40 nC charge, 4 mm bunch length, 30 MeV single bunch at 1 mm offset from the structure axis.
The structure is currently under development, and planned to be tested at AWA facility in near future.
Planned Experiment
12
Summary
• We are developing a hybrid mode damped DLA structure.
• Structure will be tested at AWA facility along with a conventional DLA structure as a comparison.