L'Gatignon ABATBEA

1
L.Gatignon / AB-ATB-EA

• INTRODUCTION

• Which experiment is where
• Aims, requirements of users
• Optics principles for areas
• Transport/Turtle versus MAD
• Optics drawings
• Momentum definition
• Collimation

Qualitative rather than quantitative !!!
2
Layout

• 8 beams running at the
• same time
• 15 test facilities
• 5 installed experiments
• 6.3 km of beam lines
• 4 Experimental halls

3
WEST AREA LAYOUT
LHC test
4
NORTH AREA
LHC test
5
2003 Schedule
West Area
EHN1
ECN3
EHN2
? 70 user changes Many more beam changes
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2003 Schedule per category of users
LHC tests
West Area 90 LHC
EHN1 75 LHC
Physics 100
(Of proton Period)
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Overview of beam lines

• X5, X7 Two versatile p, e, m test beams from 5
  to 250 GeV/c in the West Area
• GIF Gamma Irradiation Facility in the West
  Area, at the end of X5
• H2, H4 High energy test beams (up to 400 GeV),
  also physics and ion beams, very
  high quality electron beams
• H6 Test beam up to 205 GeV/c, flexible,
  intensity up to few 107 ppp
• H8 High energy test beam, up to 400
  GeV/c
• M2 High-intensity muon beam up to 190
  GeV/c, High intensity (108 ppp)
  hadron beam up to 280 GeV/c
• P41,P61 Primary proton or ion beam, some
  possibilities for secondary beams
• P42K12 Kaon beams for NA48/2
• This is a unique facility world-wide!

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Example of installations in EHN1
CMS/ECAL in H4 beam
ATLAS/MUON in H8 beam
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The GIF Facility
20 Curie Cs137 source (some wishes to upgrade to
higher intensity) Parasitic ms from
X5 Possibility to use e- Heavily exploited,
over-booked all the time Runs all year round
with source only. Very unique facility!!!
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Medium Term Plan
NA48/2 New experiment starting in
2003 NA60 No physics data taken
yet COMPASS First real data in 2002
West Area stops end 2004 North Area continues
after 2005 for CMS calibration and one beam for
radiation testing Optimisation of use of test
beams in the SPS North Area
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Or, in practical terms..
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Users of the beam lines
Two main categories of users exist
EXPERIMENTS
TESTS
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PARTICLES IN A MAGNETIC FIELD
F
In a magnetic field, the force is
perpendicular to the velocity of the particle and
to the field F q v x B
B
In a uniform magnetic field the deflection of a
particle depends on the product of field B and
length L of the magnet
q rad 0.3 q BL Tm / p GeV/c
BL Tm
For a given magnet, the length is fixed but
the field B (and hence the BL) can be controlled
via its current I. In the experimental areas
the current is constant over the spill !
Io
I A
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BENDs and TRIMs
BL
q 0.3
A dipole acts like a prism
p
400 GeV
350 GeV
300 GeV
250 GeV
200 GeV
Together with a collimator, a dipole can be used
to define a momentum p
The Dp depends on the gap width
Bends have a nominal deflection of the beam axis,
Trims are correctors only (nominal field is
0). Big spectrometer magnets in the experiments
are also called bends!
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QUADRUPOLES
B field line density Focus in Horizontal
plane Defocus in Vertical plane or
vice versa
B, F, Gradient
Like an optical lense !
Distance from axis
f
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Basic optics principles

• To focus in both planes one needs at least two
  quadupoles (doublet)
• but horizonal and vertical magnification are
  rather different
• and there are no degrees of freedom (apart from
  H-V flip)
• A triplet can also focus in both planes, but
  also
• Mx and My can be equal
• Mx and My can be tuned
• In the optics diagrams shown, the lines can be
  understood in two ways
• Trajectories of specific particles (with e.g. Xo
  0 or Xo 0)
• Drawings of transfer matrix elements

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Matrix elements
Xo Xo
X1 X1
Some optics elements
Transfer matrix R
R11 R12 R21 R22
X1 X1
Xo Xo
R11 Xo R12 Xo R21 Xo R22 Xo


1 L 0 1
1 0 -1/f 1
Quadrupole
e.g. Drift space L
(f focal length)
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Generalisation to real systems
The matrix of a system is the product of the
individual matrices
Q1
Q2
Horiz
X X Y YL Dp/p
But also include Y-coordinates Momentum p
Vert
1 L1 0 1
1 0 -1/f1 1
1 L2 0 1
1 0 1/f2 1
1 L3 0 1
Xo Xo
6x6 matrices !
Doublet optics
TRANSPORT
RUN25/02/03  POSITION TYPE STRENGTH
H O R I Z O N T A L V E R T I
C A L D I S P E R S I O N
METERS TM,T/MM R11 R12
R21 R22 R33 R34 R43 R44
R16 R26 R36 R46
T/M2M MM/MM MM/MR MR/MM MR/MR
MM/MM MM/MR MR/MM MR/MR MM/PC MR/PC
MM/PC MR/PC


0.000 3 TARGET 1.000 0.000
0.000 1.000 1.000 0.000 0.000 1.000
0.000 0.000 0.000 0.000 9.000 3
1.000 9.000 0.000 1.000
1.000 9.000 0.000 1.000 0.000
0.000 0.000 0.000 11.000 5 Q1 61.9865
0.820 9.257 -0.175 -0.751 1.192
12.851 0.198 2.970 0.000 0.000 0.000
0.000 19.000 3 -0.576
3.250 -0.175 -0.751 2.772 36.609 0.198
2.970 0.000 0.000 0.000 0.000
21.000 5 Q2 -61.9865 -1.058 2.276
-0.322 -0.253 2.644 35.592 -0.322 -3.955
0.000 0.000 0.000 0.000 30.000 3
-3.955 0.000 -0.322 -0.253
-0.253 0.000 -0.322 -3.955 0.000
0.000 0.000 0.000 30.000 3 FOCUS
-3.955 0.000 -0.322 -0.253 -0.253
0.000 -0.322 -3.955 0.000 0.000 0.000
0.000
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DISPERSION
Dispersion is necessary in secondary (tertiary)
beams to define the momentum
Momentum slit

• However, for good beam performance you must
• optimise momentum resolution
  ? focus at momentum slit
• get rid of dispersion at the end of the beam line
  ? field lense

Focus at momentum slit
B1
Field lense
B2
Either B1 or B2 is the momentum reference
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Optics general observations

• Beams are normally small in a focus Except when
  the dispersion is very large at the focus or in m
  beam
• Experimental targets are normally in a
  focus They want a small spot Less sensitive to
  changes of angle at primary target
• A Trim (or Bend) in a focus will NOT affect the
  position of the beam at the next focus (e.g.
  at the experiment) But it will affect the angle
  and it may improve transmission. Trims in a
  parrallel section have the maximum steering
  effect.
• Material on the beam has less effect if in a
  focus Even if scattered, it particle come back
  to the same point

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Optics calculations

• Optics drawings can be interpreted as
• matrix element representations
• trajectories of specific particles
• For optics design the matrix element approach
  must be used
• The TRANSPORT program calculates transfer matrix
  elements and adjusts
• the individual parameters (f, L, etcetera) to fit
  the optics requirements.
• The result is a TABLE with transfer matrix
  elements and an optics drawing.
• The effect of aperture limitations (e.g.
  collimators) and material on the beam
• can only be evaluated in the trajectory approach.
• The DECAY TURTLE program is used to track
  individual particles though
• the beam line and to provide plots of particle
  properties, such as positions,
• angles and momenta, as well as a table of
  particle losses along the beam.

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TRANSPORT TABLE
X5 DEVELOPMENT FOR 250 GEV VERSION - LGA 090490

TRANSPORT RUN 4/09/02   POSITION TYPE
STRENGTH H O R I Z O N T A L
V E R T I C A L D I S P E
R S I O N METERS TM,T/MM
R11 R12 R21 R22 R33 R34
R43 R44 R16 R26 R36 R46
T/M2M MM/MM MM/MR
MR/MM MR/MR MM/MM MM/MR MR/MM MR/MR
MM/PC MR/PC MM/PC MR/PC


0.000 3
X5TG 1.000 0.000 0.000 1.000
1.000 0.000 0.000 1.000 0.000
0.000 0.000 0.000 14.500 3
1.000 14.500 0.000 1.000 1.000
14.500 0.000 1.000 0.000 0.000 0.000
0.000 17.448 5 Q1 23.4981 0.915
16.127 -0.057 0.088 1.088 18.807 0.060
1.964 0.000 0.000 0.000 0.000
18.300 3 0.866 16.202
-0.057 0.088 1.139 20.480 0.060 1.964
0.000 0.000 0.000 0.000 21.248 5
Q2 23.4981 0.629 15.072 -0.102 -0.844
1.423 28.235 0.135 3.373 0.000
0.000 0.000 0.000 26.946 3
0.050 10.265 -0.102 -0.844 2.189
47.457 0.135 3.373 0.000 0.000 0.000
0.000 29.894 5 Q3 -16.4899 -0.252
8.357 -0.106 -0.464 2.446 54.349 0.038
1.255 0.000 0.000 0.000 0.000
30.746 3 -0.342 7.962
-0.106 -0.464 2.479 55.418 0.038 1.255
0.000 0.000 0.000 0.000 33.694 5
Q4 -16.4899 -0.681 7.055 -0.127 -0.158
2.440 55.712 -0.064 -1.058 0.000
0.000 0.000 0.000 38.496 3
-1.289 6.298 -0.127 -0.158 2.131
50.633 -0.064 -1.058 0.000 0.000 0.000
0.000 41.496 4 B1 2.3679 -1.668
5.825 -0.127 -0.158 1.938 47.460 -0.064
-1.058 0.089 0.059 0.000 0.000
42.196 3 -1.757 5.715
-0.127 -0.158 1.893 46.720 -0.064 -1.058
0.130 0.059 0.000 0.000 45.196 4
B1 2.3679 -2.136 5.241 -0.126 -0.158
1.701 43.547 -0.064 -1.058 0.396
0.118 0.000 0.000 45.896 3
-2.225 5.131 -0.126 -0.158 1.656
42.807 -0.064 -1.058 0.479 0.118 0.000
0.000 48.896 4 B1 2.3679 -2.604
4.658 -0.126 -0.158 1.463 39.634 -0.064
-1.058 0.923 0.177 0.000 0.000
49.596 3 -2.693 4.547
-0.126 -0.158 1.418 38.894 -0.064 -1.058
1.047 0.177 0.000 0.000 52.596 4
B1 2.3679 -3.072 4.074 -0.126 -0.158
1.225 35.721 -0.064 -1.058 1.668
0.237 0.000 0.000 53.296 3
-3.161 3.963 -0.126 -0.158 1.180
34.981 -0.064 -1.058 1.834 0.237 0.000
0.000 56.296 4 B1 2.3679 -3.540
3.489 -0.126 -0.158 0.987 31.808 -0.064
-1.058 2.632 0.296 0.000 0.000
56.996 3 -3.628 3.379
-0.126 -0.158 0.942 31.068 -0.064 -1.058
2.839 0.296 0.000 0.000 59.996 4
B1 2.3679 -4.007 2.905 -0.126 -0.158
0.749 27.895 -0.064 -1.058 3.815
0.355 0.000 0.000 67.771 3
-4.990 1.677 -0.126 -0.158 0.250
19.672 -0.064 -1.058 6.574 0.355 0.000
0.000 70.719 5 Q5 21.1651 -4.969
1.094 0.140 -0.232 0.075 18.026 -0.056
-0.074 7.087 -0.011 0.000 0.000
71.201 3 -4.901 0.982
0.140 -0.232 0.048 17.990 -0.056 -0.074
7.082 -0.011 0.000 0.000 74.149 5
Q5 21.1651 -4.121 0.240 0.382 -0.265
-0.117 19.188 -0.058 0.897 6.505
-0.375 0.000 0.000 75.055 3
-3.775 0.000 0.382 -0.265 -0.169
20.000 -0.058 0.897 6.166 -0.375 0.000
0.000 75.055 3 C1C2 -3.775
0.000 0.382 -0.265 -0.169 20.000 -0.058
0.897 6.166 -0.375 0.000 0.000
83.357 3 -0.603 -2.199
0.382 -0.265 -0.647 27.444 -0.058 0.897
3.052 -0.375 0.000 0.000 88.357 4
B2 5.0134 1.308 -3.524 0.382 -0.265
-0.935 31.927 -0.058 0.897 1.489
-0.250 0.000 0.000 89.017 3
1.560 -3.699 0.382 -0.265 -0.973
32.519 -0.058 0.897 1.324 -0.250 0.000
0.000 94.017 4 B3 5.0134 3.470
-5.023 0.382 -0.265 -1.261 37.002 -0.058
0.897 0.388 -0.125 0.000 0.000
94.677 3 3.722 -5.197
0.382 -0.265 -1.299 37.594 -0.058 0.897
0.306 -0.125 0.000 0.000 99.677 4
B2 5.0134 5.632 -6.520 0.382 -0.265
-1.586 42.077 -0.058 0.897 -0.004
0.001 0.000 0.000 107.457 3
8.602 -8.578 0.382 -0.265 -2.034
49.053 -0.058 0.897 0.000 0.001 0.000
0.000 110.405 5 Q6 -27.6117 10.656
-10.272 1.035 -0.904 -1.995 46.704
0.084 -2.463 0.002 0.001 0.000 0.000
117.905 3 18.419 -17.051
1.035 -0.904 -1.366 28.230 0.084 -2.463
0.007 0.001 0.000 0.000 120.853 5
Q7 24.0089 19.777 -18.152 -0.128 0.168
-1.235 23.285 0.007 -0.941 0.008
0.000 0.000 0.000 121.324 3
19.717 -18.073 -0.128 0.168 -1.231
22.842 0.007 -0.941 0.008 0.000 0.000
0.000 122.124 5 Q7 6.5153 19.487
-17.822 -0.447 0.460 -1.234 22.237
-0.013 -0.574 0.008 0.000 0.000
0.000 160.853 3 2.173
0.000 -0.447 0.460 -1.742 0.000 -0.013
-0.574 0.011 0.000 0.000 0.000
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Transport / Turtle vs MAD
Even though Tansport and MAD describe the same
optics and the same behaviour (and use the same
mathematics), they are aimed at different
uses MAD Accelerators (linear, circular),
matching of transfer lines Phase space,
emittance oriented, beta functions Starts from
an assumed (or known) initial phase
space Transport More convenient for secondary
beam lines Definition of focii, angular
acceptance Based on transfer matrix
approach Initial phase space is (rarely or) not
used There is a nice correspondence between
MAD and Transport, however the language is rather
different
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Rough correspondences
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OTHER OFFLINE SOFTWARE
The following offline programs are typically used
in the EA context

• Beatch Geometry input for installation and
  survey
• Transport Optics design, fitting
• Decay Turtle Simulation, particle tracking of
  main beam (hadrons, e)
• Halo Muon beam simulation, inside and outside
  beam tube
• Beamopt Optics drawings, detailed, from
  BeatchTransport
• Beamplt Optics drawings, simplified, based on
  Transport only
• Partprod Particle production parametrisation
• Geant, Fluka Simulation of particles in matter
• Only Beatch outputs are systematically put on the
  Web
• Transport, Turtle, Halo are usually available on
  afs in
• subdirectories of /afs/cern.ch/user/e/eagroup/data
  base/

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COLLIMATION

• Collimation is as important for beam quality as
  optics
• Optics and collimation are very much correlated

Basically we consider 4 different types of
collimators

• Dump collimators (TAX)
• Momentum slits
• Acceptance collimators
• Cleaning collimators

Sometimes individual collimators can share
several functions
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1. Dump collimators (TAX)
TAX stands for Target Attenuator eXperimental
areas
A TAX serves to stop the primary beam (e.g. in
case of access) or to define the beam acceptance
or limit its rate (by attenuation)
Target
primary beam
Acceptance defined by TAX
A TAX is a 1.6 m long water-cooled table with Cu,
Al and Fe blocks This table is motorised in the
vertical plane Through those blocks some holes of
different diameters are drilled Some holes
contain 40 120 cm of Beryllium (for
attenuation) One position ( 140 mm) is fully
plugged (DUMP) The range of the movement is
interlocked (EA safe Chain 9) TAX are also
safety elements in the Access system
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2. Momentum slit
Normally located at a dispersive focus. The
center of the gap should be at the nominal beam
axis. The aperture is proportional to the
accepted momentum band, The rate is normally also
proportional to the gap. However, the DP/p cannot
be smaller than the intrinsic resolution. Hence
the need (in general) to have a rather sharp
focus.
3. Acceptance collimator
Located where the beam is large (ideally even
parallel), Allows to define the angular aperture
of the beam, Affects therefore the rate as well,
however non-linearly.
4. Cleaning collimator
A repetition of an earlier (acceptance)
collimator. Cleans up particles scattered on the
edge of the earlier collimator
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Intensities in a secondary beam
Tertiary beam
Secondary beam
primary proton beam
x . 1012 ppp
lt 108 ppp
lt 104 ppp
Primary Target
Secondary Target
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What more is needed ?

• Correction dipoles (Trims)
• Secondary targets
• Absorbers, converters, filters
• Beam instrumentation (very different from
  transfer lines and main ring) Steering Momentum
  measurement Particle identification Spill
• Cleanup of beam Collimators Scrapers and MIBS
• Interlocks and safety Access doors Dumps Shiel
  ding Fences
• .......