1. Previous presentation
Hybrid Laminar Velocity Bunching
converging on ONE UNIQUE LAYOUT?
Outline
Two new techniques in ONE slide
1) Hybrid LVB ) Radio Frequency Focusing
Let’s start from Marcello’s Conclusion (March 16)
One unique layout
Previous presentation
Alberto Bacci, M. Rossetti Conti LNF 31

2. Previous presentation
20 MeV
ΔE =100 keV
Different Bunch Charges (very good scaling)
bunch length decreases linearly
envelope rises linearly
energy spread quasi full corrected
emittance a decreasing elbow
No Quadrupoles
→ A symmetric Beam
→ Very Good for BD
Previous presentation
C- band booster,
or X-band (**)
RF-focusing
Modular Standing Wave cavity

3. Previous presentation
Advantages of the two techniques
Long. phase space
Incorrelated Espread
Correlated Espread
Previous presentation
No Laser Heater (High incorrelate Energy Spread):
A shorter LINAC
1) RF focusing:
No FODO along the LINAC → Symmetric Beam Dynamics
2) RF focusing: very short focusing channel (15um → short channel → 1-5 um)
Very good performances (No Mag. Compressor):
Ipeak 2÷4 kA; Low emit. <1um; Very Low E_spread 5x10^-4

4. Previous presentation
Marcello’s Conclusions: Trying to converge in ONE layout
L1 booster
Mag. Compressor
L2 booster
Previous presentation
8.7 m
Injector exit
STARTING FROM L1 Booster
Cristina’s solution (X-band or C-band)

5. 2m C-band TW – ELI-like (x-band injection)
(1) Testing the L1 Cristina layout (2) A common injector
10.5 m
Injector exit
1.6 m drift
L1 x-band
Cristina’s layout considering Quads room
L1 18 m
2m C-band TW – ELI-like (x-band injection)
Previous presentation
(2) A common injector
Modular SW ÷ 5 sectors
2 meters
Modular SW ÷ 3 sectors
1.2 meters
Velocity Bunchig should benefits from Standing Wave RF Focusing
Anna is going to test her results by this layout

6. Previous presentation
Units
Xband
FEL-SASE
1 GeV
EuPRAXIA
FEL-CDR
Witness bunch
HLVB
No.bunches
1 – (maybe 2)
Bunch separation ps
(maybe 83)
Rep. rate Hz
10 – 100 10
Injector energy
GeV
0.15
Xband Acc. Gradient
MV/m
> 70
Exit linac energy
1. – (1.5)
0.5
2016
2017 ?
Rms Energy Spread %
<1.
<1
 0.1 MeV)
Peak current kA 2. 3
1.5
2.3 (1.1 whole)
Bunch charge pC
100 30
 100
Bunch length rms
mm (fs)
15 (50)
3 (10)
2 (7)
 8 (25)
Rms norm. emittance mm
< 1.
<1.5
<0.6 
Slice Brightness 
A/m^2 
 4.8e16
Slice Length
0.7
0.75
 0.7 fixed for binning
Slice Charge
4.5
7.5
3.7
 5.4
Slice Energy Spread
0.1
 0.04
Slice norm. emittance 1
 0.28
Previous presentation
Qui devo inserire tabella con valori per un fascio accelerato

7. (1) Testing the L1 Cristina layout and tray to avoid Quads
L1 x-band booster
Peak
field
Energies up to 500 MeV
Envelops [mm]
Energy spread keV/100
Emittance [mm]
Space charge dominated beams do not like asymmetric dynamics

8. (1) Final focusing channel by 5 Permanet Quads (20 cm)
sig_x, sig_y
20 cm device
45 Interaction Point
Zoom box
sig_z
<2µm
millimeters

9. Almost Finished activities of this analysis
Comparison RF focusing for (already verified on literature):
1) HFSS 3D field map vs
2) multipolar expansion
Whole Line Optimization optimization (inj+booster) by the evolutive code GIOTTO
For best performances:
It’s not possible uncouple injector and booster
A movable Diagnostic system, in the DRIFT ZONE, to be removed after validation

10. Diagnostic, from last meeting
Cianchi’s suggestion :
Movable diagnostic system to be removed, for additional acc.,
after the Hybrid Laminar VB validation