spl to ps2 transfer line and ps2 injection requirements
DESCRIPTION
SPL to PS2 transfer line and PS2 injection requirements. W . Bartmann, Ch. Hessler , B. Goddard , M . Eshraqi , M. Meddahi, A. Lombardi 3 rd SPL Collaboration Meeting, 11 th - 13 th Nov 09. PS2 and Transfer Lines Overview. SPL. based on PS2 version from 17. Dec. 2008. - PowerPoint PPT PresentationTRANSCRIPT
SPL to PS2 transfer line and PS2 injection requirements
W. Bartmann, Ch. Hessler, B. Goddard, M. Eshraqi, M. Meddahi, A. Lombardi
3rd SPL Collaboration Meeting, 11th - 13th Nov 09
2
PS2 and Transfer Lines Overview
850 900 950 1000 1050 1100 1150 1200 1250 1300 1350
2150
2200
2250
2300
2350
2400
2450
2500
2550
2600
2650
~ 11 m
P S 2
T T 11
T T 10 (new )
S P S
T T 10 (o ld )
T T L1
T I 2
T T E A
T D 1
based on PS2version from17. Dec. 2008
SPL
3
Driving Parameters for TTL1
LP-SPL LP-SPL-5G HP-SPL
Kinetic energy [GeV] 4 5 5
Repetition rate [Hz] 2 2 50
Pulse length [ms] 1.2 1.2 0.4
Average pulse current [mA] 20 20 40
Beam power [MW] 0.192 0.24 4
Max. fract. loss [m-1](due to Lorentz stripping)assuming max. Ploss =0.1 W/m
5.2e-7 4.17e-7 2.5e-8
Max. dipole field [T] 0.115 0.0950 0.0858
Min. rho [m] 141 206 228
Expression fractional loss from A.J. Jason et al, IEEE Trans.Nucl.Sci. NS-28, 1981http://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=4331890&isnumber=4331887
4
Beam Line Geometry
1 0 0 m
S P L en d p o in t h o rizo n ta lb en d in gm ag n e ts
v e rtica lb en d in gm ag n e ts
in jec tio n ch ican e m ag n e tp o in t C q u ad ru p o le s
b eam
ach ro m a t 1 ach ro m a t 2 ach ro m a t 3 ach ro m a t 4
first part compatible with HP-SPL, second part only compatible with LP-SPL @ 4 GeV
second part can be compatible with LP-SPL @ 5 GeV if 7.2 m (instead of 5.75 m) long dipoles are used
large slope of 8.1%
5
Optics Simulation
SPL PS2
6
Optics Simulation
7
Aperture Calculation
max
1.11.1,
cop
pDNyx phys
N = 6co = 5 mm
beam envelope:
s [m]
x,y [m]
8
Multi-particle Simulations
Simulation code: TraceWin
Beam current: 62 mA
Emittance growth (H/V): 23% / 2%
Energy spread increase: from ±1.5 MeV to ±7 MeV
M. Eshraqi
9
Trajectory Correction
100 uncorrected trajectories:
10
Trajectory Correction: Results
Each quadrupole equipped with a H/V monitor 2 quadrupoles out of 3 equipped with a corrector
Correction OK
11
Outlook TTL1
Complete new PS2 LSS1 layout to disentangle injection/extraction region
New TTL1 version (work in progress):
12
Parameters for ISOLDE/EURISOL Beam Lines
ISOLDE EURISOL
LP/HP-SPL LP-SPL HP-SPL
Kinetic energy [GeV] 1.5 2.5 2.5
Repetition rate [Hz] 1.25 1.25 50
Pulse length [ms] 1.2 1.2 0.8
Average pulse current [mA] 20 20 40
Beam power [MW] 0.045 0.075 4
Max. fract. loss [m-1](due to Lorentz stripping)assuming max. Ploss =0.1 W/m
2.22e-6 1.33e-6 2.5e-8
Max. dipole field [T] 0.254 0.172 0.149
Min. rho [m] 29.5 64.1 74.0
Expression fractional loss from A.J. Jason et al, IEEE Trans.Nucl.Sci. NS-28, 1981http://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=4331890&isnumber=4331887
Extraction from SPL to ISOLDE
Input parameters p+ beam
1.4 GeV p+, Br = 7.14 Tm
42 kW
0.29 T maximum bending field (0.1 W/m)
0.65 m cryomodule radius
Same radius assumed for Warm-Cold transition
Results Use 0.22 T dipole, 4 m long, 123 mrad
0.15 m clearance at cryomodule/W-C transition
Pulsed dipole, 1.25 Hz repetition rate
Stripping foil outside the extraction region
Losses in extraction dipole N/N0 ~1e-7 (0.02 W/m) from stripping foil, 4.3 e-5 (1.8 W)
13
Layout for 1.4 GeV p+ extraction
13 m
9 m
CryomoduleW-C transition
W-C transition
2 m
Cryomodule
0.5 m
0.22 T
0.65 m
0.15 m4 m
6.5 m
Extraction dipole
123 mrad
to foil
14
Extraction from SPL to EURISOL
Input parameters:
H- beam
2.5 GeV H-, Br = 11.03 Tm
6 MW (!)
0.15 T maximum bending field (0.1 W/m)
0.65 m cryomodule radius
Same radius assumed for Warm-Cold transition
Results
Use 0.15 T dipole, 8 m long (!), 109 mrad
0.15 m clearance at cryomodule/W-C transition
15
Layout with 9m available drift
13 m
9 m
CryomoduleW-C transition
W-C transition
2 m
Cryomodule
0.5 m
0.15 T
0.49 m
8 m
6.5 m
Extraction dipole
109 mrad
0.5 m
16
Does not work!!
17
Layout with minimum possible drift
16.4 m
12.4 m
Cryomodule
WCT WCT
0.5 m
Cryomodule
0.5 m
0.15 T
2.75 m
7.2 m
Extraction dipoles
112 mrad
0.5 m 0.15 m
0.15 m
2 m
5.2 m
0.43 m
Length/Height of WCT for 13 m period
13 m
12.1 m
Cryomodule
WCT WCT
0.9 m !!!
Cryomodule
0.5 m
0.15 T
3.05 m
6.5 m
Extraction dipoles
124 mrad
0.15 m
0.5 m
0.55 m
0.15 m
18
Stripping foil thickness optimisation
0 500 1000 1500 2000 2500 3000 3500 4000 4500 500010
-6
10-5
10-4
10-3
10-2
10-1
100
Foil thickness [ug/cm2]
Loss
fra
ctio
n
Total loss
Elastic scattering
Inelastic scatteringUnstripped H-
Unstripped H0
large angle single Coulomb scattering
0 500 1000 1500 2000 2500 3000 3500 4000 4500 500010
-6
10-5
10-4
10-3
10-2
10-1
100
Foil thickness [ug/cm2]
Loss
fra
ctio
n
Total loss
Elastic scattering
Inelastic scatteringUnstripped H-
Unstripped H0
large angle single Coulomb scattering
2.5 GeV3.2x10-5 loss6 MW 192 W
1.4 GeV4.3x10-5 loss42 kW 1.8 W
19
Loss minimum for a foil thickness of 1200 – 1300 ug/cm2
20
PS2 Injection Requirements
Potential H- injection issues for Foil stripping Longitudinal Painting constraint on dispersion in injection region with Δε from
dispersion mismatch Heating: Injection repetition rate, intensity Transverse emittance beam size on foil Uncontrolled losses :
Halo – collimation in TL? Kinetic Energy significantly less than 4 GeV scattering, aperture, …
Potential H- injection issues for Laser stripping Longitudinal Painting large momentum range would dramatically increase required
laser power Bunch length increases Laser average power, optimisation to study Energy jitter increases range of frequencies to be swept 100 keV jitter OK Trajectory jitter
Match laser and ion beam as much as possible, vertically more stringent – more laser power required (to get necessary power density)
Kin Energy significantly less than 4 GeV Laser power, emittance growth
21
Energy Jitter
Need divergence in Laser beam to cover the spread of exciting resonance frequencies due to Doppler broadening
Laser frequency range is determined by effective momentum spread
To have no big effect, need energy jitter one order below initial momentum spread ΔEkin = 10-4 GeV
Laser stripping much more difficult for significantly reduced kinetic energy (e.g. 3.5 GeV) – can only access n=2 state with 1064 nm which means huge emittance growth in last magnetic stripping step
Den at 4 GeV
1064 nm
Conclusion TTL1
TTL1 design: First part compatible with all SPL versions
Second part only with LP SPL (4 GeV), if LEP yokes not used but longer magnets also for LP SPL (5 GeV)
8.1 % slope civil engineering!
Multiple particle simulations Emittance growth (H/V): 23% / 2%
Energy spread increase: from ±1.5 MeV to ±7 MeV
Trajectory correction OK
Outlook: TTL1 optics studies ongoing because of new PS2 injection region design
22
Conclusion Extraction and PS2 Injection
Extraction to ISOLDE OK
Extraction to EURISOL Not feasible within constraints!
2 possibilities:
Opening up distance between cryomodules to 16.4 m and reducing radius of WC transition to 43 cm
Within given 13 m, reduce WC transition length to 90 cm and radius to 55 cm
PS2 Injection
Study on H- injection is work in progress…
Significantly reduced energy makes injection much more difficult!
Large momentum range and bunch length increase Laser power need to optimise
Energy jitter of 100 keV OK
Losses in injection region Halo collimation in TL?
23
Back up slides
24
25
Beam and Twiss Parameters
x plane y plane
norm. 1s emittance [µm] 0.351 0.350
beta [m] 106.5 117.3
alpha -0.055 -1.352
dispersion [m] 0 0
dispersion derivative 0 0
SPL end point (Source: M. Eshraqi):
x plane y plane
beta [m] 15 15
alpha 0 0
dispersion [m] -0.4 0
dispersion derivative 0 0
Injection point (Source: W. Bartmann):
26
Trajectory Correction: Assumed Errors
Quadrupole displacement errors: Gaussian distribution in x/y with s = 0.2 mm, cut at 3s
Dipole field errors: Gaussian distribution of deflection with s = 10 µrad, cut at 2s (→ relative field error of 5e-4)
Dipole tilt errors: Gaussian distribution with s = 0.2 mrad, cut at 4s
Monitor errors: Flat random distribution of ±0.5 mm in both planes
Injection error: Gaussian distribution of position / angle with s = 0.5 mm / 0.05 mrad, cut at 2s
Monitor failure probability: 5%