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RFQ

Design

BNL RFQ for H minus was design and febricated by LBL personlas².

TABLE 1 General Characteristics
ion
protons
H-
Input Energy
35
keV
Output Energy
753
keV
Vane Length
161.89
cm
Surface Field
20.3
MV/m
Kilpatricks
1.38
at unmodulated vane
1.47
at worst spot
Current Limit
>100
mA
Peak Cavity Power
100.5
kW

TABLE 2A: STRUCTURE PHYSICS DESIGN PARAMETER
Section
KE

keV
phi_s

deg
a

cm
m

A

Length

cm
Input
35
-90 °
1.871
1.000
0.000
Radial Match
35
-90 °
0.418
1.0000
0.0000
3.86
Shaper
68
-76.3 °
0.384
1.182
0.102
57.29
Gentle Buncher
180
-50 °
0.327
1.543
0.344
29.69
Accelerator
753
-40 °
0.262
2.052
0.597
71.05
161.89

                                                          TABLE 2B:   PHYSICS PARAMETERS
Vane Voltage
67.2
kV
r0  
0.418
cm
B (Focussing Par)
9.079
Frequncy
201.25
MHz
Focusing Phase Adv/period
39.2°
deg , 50 mA
Number of RM cells
6

TABLE 3: CAVITY PARAMETERS
Vane Length 161.89 cm
r0 0.418 cm
Unloaded Frequncy 207.5 MHz
Number of VCR sets 3
VCR Frequncy Shift -9.3 MHz
Number of Tuing bars 4 total
Tuning bar frequncy shift +3 MHz
Theoretical Q 11372
Actual Q/ Theoretical Q 57 %
Vane Voltage 67.2 kV
Cavity Power 100.5 kW
Beam Power (50 mA) 36 kW
Total Power 136.5 kW
Cavity Power Density 621 W/cm times duty factor
del f0/del R -16.5 MHz/cm
del f0/ del (radius vane pos) 156 MHz/cm
del f0/del (tuning bar area) 0.94 MHz/cm2 /bar

TABLE 4: CAVITY POWER DISTRIBUTION
Q 0.57 Q0
Store Energy 0.50 joules, full cavity
Vane Voltage 67.2 kV
BNL Duty Factor 0.007 Maximum BNL spec.
FNAL Duty Factor 0.0015 Tpical FNAL spec.
Power Density 4.3 Watts/cm (maximum)
Wall  H  Field 3381 Amperes/meters
Distribution, full cavity, 0.007 duty factor
Outer Wall 1.85 Watts/cm
Tuning bar flat 0.99
73° Vane side 1.30
Notch, tip 0.21
4.35 Watts/cm, Total

TABLE 5: CAVITY GEOMETRY
Cavity Radius 15.71 cm
r0 0.418 cm
Slab Angle 73 ° deg
Cutting Allowance 0.0896 cm
Side Intercept (VRO0 -0.9 cm
Vane Tip Intercept -0.5937 cm
Vane Base Full Width 7.0 cm
Tunning Bar Side Height 4.77 cm

TABLE 6: REFERCE POINTS
Reference Point X (cm) Y (cm)
Vane Tip 0.0000 0.4180
73 °around 0.3997 0.7138
Start of Notch 0.8500 2.1865
Inside Notch 0.8500 3.0000
End of Notch 1.1923 3.0000
Start of Side Flat 3.5000 10.5480
End of Side Flat 3.50000 15.3152
Cavity Symmetry Point 11.1086 11.1086

TABLE 7: Input Beam Characteristics
Current Beta Alpha Emittance (Normalized, 100%)
5 mA 5.2 cm 1.27 0.10 pi cm-mrad
50 mA 9.4 cm 2.85 0.10 pi cm-mrad
100 mA 14.8 cm 4.87 0.10 pi cm-mrad

TABLE 8: OUTPUT BEAM CHARACTERISTICS; 90% CONTOUR
Current Transmission ßX AlphaX EmiitnaceX ßY AlphaY EmittanceY
5 mA 100 % 5.6 cm -1.28 0.07 pi cm-mrad 8.9 cm 1.53 0.10 pi cm-mrad
50 mA 97 % 6.3 cm -1.25 0.12 pi cm-mrad 12.6 cm 2.40 0.11 pi cm-mrad
100 mA 81 % 7.1 cm -1.32 0.11 pi cm-mrad 13.0 cm 2.43 0.12 pi cm-mrad

TABLE 8A: OUTPUT BEAM CHARCTERISTICS, 90% CONTOUR, LONGITUDINAL
Current Del W    (keV) Del Phi  (deg)
5 mA ± 34 ± 27 °
50 mA ± 14 ± 33 °
100 mA ± 19 ± 39 °

Transmission at 50 mA degrqdes to 81% with a normalized input emittance inreased to 3.0 pi cm-mrad.

SIMULATIONS:

          There were two sets of simulations were done for RFQ performance with respect to RFQ power. First set does includ the longitudinal losses and second set does not.

SET1

 

SET 2

EXPERMENTS:

My house

Picture of my mansion in the hills above Naples, note the hole in the roof where the lightning struck. The local paper took this shot.

÷

REFERENCES

1:" Design, Fabrication, and Testing of the BNL Radio Frequncy Quadrupole Accelerator" By H. Brown, T.         Clifford, S. Giordano, F. Khiari, R. McKenzei-Wilson, M. Puglisi, P. Warner

2: " BNL/FNAL RFQ Specifications" By John Staples. LBL.

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