Heat deposition in superconducting magnets for a beta decay storage ring

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


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


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


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.


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


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


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.


The Decay Products in the arcs

s (m)

Dep

osite

d P

ower

(W

/m)

Courtesy: A. Chancé

Arc, repetitive pattern

Dipole


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


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


“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


Lattice Model, ROT-DEFI

z

y

x

x’

Z’

CosSin

SinCos

rixInverseMat

0

010

0

Offset = InverseMatrix * NewCoordinates - OldCoordinates


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


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


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


FLUKA

ACCIM(Survey data)

FLUKA geo (input cards)

ACCSIM(x,y,s) ACCSIM FLUKA


FLUKA

Geometry generation

Particle data conversion

Create model in ”Beam Optics” beam code!!!

Today Future

Interface package


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


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.


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


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


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


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


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


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.


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?


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


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.

Documents

Heat deposition in superconducting magnets for a beta decay storage ring