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Heat deposition in superconducting magnets for a beta decay storage ring
E.WildnerF. Cerutti F. Jones, Triumf (ACCSIM)
FLUKA user meeting, 11/09/07
1
Beta Beam - Loss Deposition, FLUKA meeting, E.Wildner
Overview
The beta beam complex Losses and loss management in
decay ring The arc-layout, the magnets Choice of representative model The beam code ACCSIM,
developments Interfacing ACCSIM and FLUKA Results and Future Work
Constraint explaining some of the choices and shortcuts:
2 months to develop beam code for the application, interface (beam-code FLUKA) and FLUKA modeling and runs
Beta Beam - Loss Deposition, FLUKA meeting, E.Wildner 3
EURISOL Scenario
Aim: production of (anti-)neutrino beams from the beta decay of radio-active ions circulating in a storage ring Similar concept to the neutrino factory, but parent particle is a beta-active
isotope instead of a muon.
Accelerate parent ion to relativistic max Boosted neutrino energy spectrum: En2Q Forward focusing of neutrinos: 1/
EURISOL scenario Ion choice: 6He and 18Ne Based on existing technology and machines Study of a beta-beam implementation at CERN Once we have thoroughly studied the EURISOL scenario, we can “easily”
extrapolate to other cases. EURISOL study could serve as a reference.
Neutrino detector
Ions move almost at the speed of light
EURISOL scenario
Beta Beam - Loss Deposition, FLUKA meeting, E.Wildner 4
Possible Beta Beam Complex
.
Neutrino
Source
Decay Ring
Ion production ISOL target &
Ion source
Proton Driver SPL
Decay ring
B = 1500 Tm B = ~6 T C = ~6900 m Lss= ~2500 m
6He: = 100 18Ne: = 100
SPS
Acceleration to medium
energy RCS, 1.5 GeV
PS
Acceleration to final energy
PS & SPS
Beam to experiment
Ion acceleration
Linac, 0.4 GeV
Beam preparation ECR
pulsed
Ion production Acceleration Neutrino source
Low-energy part High-energy part
Detector in the Frejus tunnel
Existing!!!
8.7 GeV
93 GeV
Beta Beam - Loss Deposition, FLUKA meeting, E.Wildner 5
Particle Turnover
~1 MJ beam energy/cycle injected equivalent ion number to be removed
~25 W/m average
Momentum collimation: ~5*1012 6He ions to be collimated per cycleDecay: ~5*1012 6Li ions to be removed per cycle per meter
p-collimation
me
rgin
g
decay losses
inje
ctio
n
Straight section
Straight section
Arc
Arc
Momentum
collimation
Beta Beam - Loss Deposition, FLUKA meeting, E.Wildner 6
The Decay Ring Optics
A. Chance et al., CEA Saclay
-5
0
5
10
15
20
0 1000 2000 3000
b1/2 (m) bx1/2
by1/2
Dx
nx = 18.23
ny = 10.16
s (m)
xb
Opt
ical
fun
ctio
ns (
m) primary
collimatoryb
Decay ring:• C~7km• LSS~2.5 km
One straight section used for momentum collimation.
Beta Beam - Loss Deposition, FLUKA meeting, E.Wildner
Particle removal & loss
Arcs Decay products
Straight section Merging increases longitudinal beam
size Momentum collimation
Decay products Primarily accumulated and extracted
at end with first dipole to external dump.
Not treated yet:Betatron-Collimation Emergency cases (failure modes)
7
Beta Beam - Loss Deposition, FLUKA meeting, E.Wildner 8
Large Aperture Requirements
aperture
child beams
ion beam
absorber
child beams
ion beam
absorber
8 cm radius needed for the horizontal plane where the decay products cause daughter beams + 1 cm for the sagitta (no curved magnet)
4 cm for the vertical plane
6Li 3+
18F 9+
Absorber
Dipole
Beam Pipe
Beta Beam - Loss Deposition, FLUKA meeting, E.Wildner 9
The Large Aperture Dipole, first feasibility study
high tip field, non-critical6 T
LHC ”costheta” design
Courtesy Christine Vollinger
Good-field requirements only apply to about half the horizontal aperture.
Beta Beam - Loss Deposition, FLUKA meeting, E.Wildner 10
The Decay Products in the arcs
s (m)
Dep
osite
d P
ower
(W
/m)
Courtesy: A. Chancé
Arc, repetitive pattern
Dipole
Beta Beam - Loss Deposition, FLUKA meeting, E.Wildner 11
Heat Deposition Calculations
Need to interface beam code and code for tracking particles in matter
Choice:
Beam Code: ACCIM (Developed at TRIUMF, many options developed specifically for the decay simulations, responsible Frederick Jones, TRIUMF)
Particle Tracking in Matter: FLUKA
"FLUKA: a multi-particle transport code",A. Fasso`, A. Ferrari, J. Ranft, and P.R. Sala,CERN-2005-10 (2005), INFN/TC_05/11, SLAC-R-773 "The physics models of FLUKA: status and recent developments",A. Fasso`, A. Ferrari, S. Roesler, P.R. Sala, G. Battistoni, F. Cerutti, E. Gadioli, M.V. Garzelli, F. Ballarini, A. Ottolenghi, A. Empl and J. Ranft,Computing in High Energy and Nuclear Physics 2003 Conference (CHEP2003), La Jolla, CA, USA, March 24-28, 2003
Beta Beam - Loss Deposition, FLUKA meeting, E.Wildner
Heat Deposition Geometry Model, one cell
Absorbers
B
B (new design)
BB
Q
Q (ISR model)
Q
No BeampipeConcentric cylinders, copper (coil), iron (yoke)
”Overlapping” Quad to check repeatability of pattern
Element name Gradient He/Ne [T/m] Strength [m-2]
QF 45.3285/27.1148 0.048483361
QD -29.5596/-17.6821 -0.031616691
Element name Field [T] Length [m] Bending Angle Radius [m]
B 6.006/3.593 5.6866 /86 155.669
18.4/12.4
12.0/9.0
Cu
Fe
20.0/20.0
Beta Beam - Loss Deposition, FLUKA meeting, E.Wildner
“Classic” Model/Lattice Model
”Classic” model SimpleGeoReference calculation
A lattice modelScoring in coilsUsing common variables from ROT-DEFI in the magnetic field description
Arc cell Lattice
“Beam Optics”
“Mathematica”
Survey data
“Mathematica”
Data for Simplegeo Data for Fluka
“SimpleGeo” “Fluka”
Tests + 3D display
Tests + display
Comparison
Check of geometry description
Beta Beam - Loss Deposition, FLUKA meeting, E.Wildner
Lattice Model, ROT-DEFI
z
y
x
x’
Z’
CosSin
SinCos
rixInverseMat
0
010
0
Offset = InverseMatrix * NewCoordinates - OldCoordinates
Beta Beam - Loss Deposition, FLUKA meeting, E.Wildner
Magnetic Field, ROT-DEFI
(x1,z1)
(x2,z2)
(x0,z0)
d
z
x
y0
d xlocal
y
kxB
kyB
y
x
Magnetic field routine:In Fortran Common, knowing region number: offset and angle for each magnetlength of element
INCLUDE(“RTDFCM”)
Project field component in x direction on FLUKA (x and z) axes
Beta Beam - Loss Deposition, FLUKA meeting, E.Wildner 16
Accsim, developed at TRIUMF, is a multiparticle tracking and simulation code for synchrotrons and storage rings.• Some applications: CERN (S)PS(B), KEK PS, J-PARC, SNS, ... • Incorporates simulation tools for injection, orbit manipulations, rf programs, foil, target & collimator interactions, longitudinal and transverse space charge, loss detection and accounting.• Interest for Betabeam: to provide a comprehensive model of decay ring operation including injection (orbit bumps, septum, rf bunch merging), space charge effects, and losses (100% !)
• Needed developments for Betabeam:• Arbitrary ion species, decay, secondary ions.• More powerful and flexible aperture definitions (for absorbers)• Tracking of secondary ions off-momentum by >30% (unheard of in conventional fast-tracking codes)• Detection of ion losses: exactly where did the ion hit the wall?
-- a challenge for tracking with the usual ”element transfer maps”
The beam code ACCSIM
Beta Beam - Loss Deposition, FLUKA meeting, E.Wildner
Interface Beam Code <->FLUKA
“Beam Optics”(Survey data) Geometry data
FLUKA geo (input cards)
ACCSIM(x,y,s) ACCSIM
Mathematica(x,y,z) FLUKA
FLUKA
Mathematica(x,y,z) FLUKA
ACCSIM(x,y,s) ACCSIM
FLUKA
ACCIM(Survey data)
FLUKA geo (input cards)
ACCSIM(x,y,s) ACCSIM FLUKA
ACCSIM(x,y,s) ACCSIM
FLUKA
Geometry generation
Particle data conversion
Create model in ”Beam Optics” beam code!!!
Today Future
Interface package
Beta Beam - Loss Deposition, FLUKA meeting, E.Wildner 18
Model generation from beam survey code
start x start y start z exit x exitx y exit z angleinrad angleindeg xlength zlength length type0 0 0 0 0 0 0 0 0 0 0 SS0 0 0 0 0 0 0 0 0 0 0 Q0 0 4. 0 0 6. 0 0 0 2. 2. SS0 0 6. 0.103855 0 11.6853 0.0182651 1.04651 0.10386 5.68565 5.6866 Bend0.103855 0 11.6853 0.140377 0 12.6847 0.0365301 2.09302 0.036522 0.999333 1. SS0.140377 0 12.6847 0.176899 0 13.684 0.0365301 2.09302 0.036522 0.999333 1. SS0.176899 0 13.684 0.488324 0 19.3618 0.0547952 3.13953 0.311443 5.67807 5.6866 Bend0.488324 0 19.3618 0.634315 0 21.3564 0.0730603 4.18605 0.145991 1.99466 2. SS0.634315 0 21.3564 0.780305 0 23.3511 0.0730603 4.18605 0.145991 1.99466 2. Q0.780305 0 23.3511 0.926296 0 25.3457 0.0730603 4.18605 0.145991 1.99466 2. SS0.926296 0 25.3457 1.44488 0 31.0083 0.0913254 5.23256 0.518609 5.6629 5.6866 Bend1.44488 0 31.0083 1.55425 0 32.0023 0.10959 6.27907 0.109371 0.994001 1. SS1.55425 0 32.0023 1.66362 0 32.9963 0.10959 6.27907 0.109371 0.994001 1. SS1.66362 0 32.9963 2.38866 0 38.6362 0.127856 7.32558 0.725084 5.64018 5.6866 Bend2.38866 0 38.6362 2.67986 0 40.6149 0.146121 8.37209 0.291202 1.97869 2. SS2.67986 0 40.6149 2.97107 0 42.5936 0.146121 8.37209 0.291202 1.97869 2. Q2.97107 0 42.5936 3.26227 0 44.5723 0.146121 8.37209 0.291202 1.97869 2. SS
bb TableFormPrependTransposeAppendTransposesimplecoord, line , "start x", "start y", "start z", "exit x", "exitx y", "exit z", "angleinrad", "angleindeg",
"xlength", "zlength", "length", "type"
* ”Beam Optics : a program for analytical beam optics”Autin, Bruno; Carli, Christian; D'Amico, Tommaso Eric; Gröbner, Oswald; Martini, Michel; Wildner, Elena; CERN-98-06
Beta Beam - Loss Deposition, FLUKA meeting, E.Wildner 19
Accsim and Fluka
Accsim as event generator for FLUKA
• Identify “region of interest”: sequence of Accsim elements corresponding to the representative arc cell modeled in FLUKA.
• Tracking particles representing statistically fully populated ring (9.66×1013 He or 7.42×1013 Ne), with decay.
• Detect and record two types of events:
1. Ions that decayed upstream of the cell and have survived to enter the cell.
2. Ions that decay in the cell.
For each event the ion coordinates and reference data are recorded for use as source particles in FLUKA.
Beta Beam - Loss Deposition, FLUKA meeting, E.Wildner 20
Particle generation and treatment
1. ACCSIM tracks 6Li and 18F particle decaying in the ring up to cell entry
Start of cell
End of cell0 10 20 30 40
0.01
0.005
0
0.005
0.01
0.015
Decayed in machine with absorbers inserted in ACCSIM
Decayed in cell
2. ACCSIM gives coordinates and momentum vectors of particles just decayed in cell
3. Particles escaping the vacuum pipe are treated by Fluka
Escaping
4. We assume particle has same momentum as parent
Beta Beam - Loss Deposition, FLUKA meeting, E.Wildner 21
INCLUDE '(SCOHLP)'* to load particle properties INCLUDE '(PAPROP)'* common/scorun/iunit common/hiexit/nhi(100,300),izmax,iamax data nhi/30000*0/,izmax/0/,iamax/0/ if(iscrng.eq.1.and.JSCRNG.eq.1) thenc assuming 38=VACUUM and 28=LASTQUAD if(nreg.eq.38.and.iolreg.eq.28) thenc we select HEAVY ION if(ij.eq.-2) then nhi(ichrge(ij),ibarch(ij))=nhi(ichrge(ij),ibarch(ij))+1 if(ichrge(ij).gt.izmax) izmax=ichrge(ij) if(ibarch(ij).gt.iamax) iamax=ibarch(ij)c momentum scoring ourpla=pla if(pla.lt.zerzer) then ourpla = -pla ourpla = SQRT ( ourpla * ( ourpla + TWOTWO * AM (-2) ) ) endif write(iunit,'(i3,i4,7(1pe18.8))') ichrge(ij),ibarch(ij), * ourpla,Xx,Yy,Zz,Txx,tyy,tzz endif endif endifc FLUSCW = ONEONE LSCZER = .FALSE. RETURN END
Scoring particles coming out of cell with fluscw
FLUKA card USERWEIG
Beta Beam - Loss Deposition, FLUKA meeting, E.Wildner 22
Coordinate transformation
ACCSIM/FLUKA and inverse
We used Mathematica based on the survey options of ”BeamOptics” * to generate FLUKA Particle file
Useful if ACCSIM could integrate the transformation code
300 250 200 150 100 50 0
0.5
0
0.5
1
1 0.5 0 0.5 1 1.5
0.5
0
0.5
1
x
x
ACCSIM
FLUKA
y
y
[cm]
[cm]
* ”Beam Optics : a program for analytical beam optics”Autin, Bruno; Carli, Christian; D'Amico, Tommaso Eric; Gröbner, Oswald; Martini, Michel; Wildner, Elena; CERN-98-06
Transverse projection
Beta Beam - Loss Deposition, FLUKA meeting, E.Wildner 23
Overall Power Deposition l
Normalized to a decay rate in cell:
He: 5.37 109 decays/sNe: 1.99 109 decays/s
6Li
Compare to technical limits (10W/m):not exceeding for either ion
18F
Beta Beam - Loss Deposition, FLUKA meeting, E.Wildner 24
Overall Power Deposition ll
Normalized to a decay rate in cell:
He: 5.37 109 decays/sNe: 1.99 109 decays/s
Compare to technical limits (10W/m)• not exceeding for either ion
Total energy deposited in magnet parts
0.00
10.00
20.00
30.00
40.00
50.00
60.00
70.00
Yok
eD1
Coi
lD1
Yok
eD2
Coi
lD2
Yok
eD3
Coi
lD3
Yok
eD4
Coi
lD4
Yok
eQ1
Coi
lQ1
Yok
eQ2
Coi
lQ2
Yok
eQ3
Coi
lQ3
Abs
1
Abs
2
Abs
3
Abs
4
Po
we
r [W
]
Li
F
Beta Beam - Loss Deposition, FLUKA meeting, E.Wildner 25
Local Power Deposition
Limit for quench 4.3mW/cm3
(LHC cable data including margin)• Situation fine for 6Li• 18F: 12 mW/cm3
Local power deposition concentrated around the mid plane.
Beta Beam - Loss Deposition, FLUKA meeting, E.Wildner 26
Is model representative?
22 % leaving!
15 % entering!
Start of cell
End of cell0 10 20 30 40
0.01
0.005
0
0.005
0.01
0.015
Decayed in machine with absorbers inserted in ACCSIM
Decayed in cell
Escaping
ACCIM model = FLUKA model?
Beta Beam - Loss Deposition, FLUKA meeting, E.Wildner 27
Alternative solutions
Open Mid Plane Magnet a better solution?
Profit of work ongoing at CERNUse this model in simulations
Absorber
Liner
Cooling pipes
Beam Pipe
Absorber
Liner
Cooling pipes
Beam Pipe
Introduce a “Beam Screen”Courtesy Erk Jensen, CERN
Beta Beam - Loss Deposition, FLUKA meeting, E.Wildner
Conclusion and FutureA protocol between the beam code Accsim and the material tracking code (FLUKA) has ben developed for the beta beam studies. ACCSIM to be used for the whole accelerator chain, for decay data production.
Accsim now to be complemented with the packages made for model creation and for coordinate transformation (Accsim->FLUKA->Accsim)
First results (good for a preliminary decision taking on magnet) indicate that the deposited power is exceeding the limits locally, but not globally. Optimisation or another magnet design needed.
Model to be verified for repeatability
The structure with absorbers would need special arrangements for the impedance induced. A thick liner inside the dipole could be an alternative
Alternative dipole design with VERY large aperture or open mid-plane (new development, ongoing).
Apply simulation tools for momentum collimation.