Andrea_Pisent

Drift Tube Linac
Andrea Pisent
INFN Italy
www.europeanspallationsource.se
April 21, 2015
Overview
• DTL design
• Production critical steps
• Critical interfaces
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Schedule
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Technical performances (SoW)
•
The DTL (Drift Tube Linac) cavity is constituted of 20 modules,
assembled in 5 tanks, composed of 4modules each, for a
total length of approximately 40 m.
•
This profile describes the life cycle phases of the DTL
regardless of the responsibilities assigned to contributors of
this Scope of Works.
1.
2.
3.
4.
5.
6.
7.
•
DTL design
Manufacturing and test of components
Assembly, low power test and tuning of each tank.
Transport and Installation in the ESS tunnel in Lund
Check out and RF conditioning to full power
Beam commissioning in two steps, beam dump after tank 1
and tank 5
Operation with the other Accelerator components (and
neutron production target).
First tank
This scope of work describes the points from 1. to 6.
CERN-INFN prototype
Istituto Nazionale di Fisica Nucleare (Italy)
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DTL Input Constraints
(after the design update in 2013)
Requirement
Particle type
Input energy
Output energy
Input current
Input emittance
Emittance increase in the DTL
Beam losses
RF frequency
Duty cycle
Peak surface field
RF power per tank
Module length
Focusing structure
Target value
H+
3.62 MeV
90 MeV
62.5 mA
0.28 mm mrad
0.15 deg MeV
<10%
<1 W/m
352.21 MHz
<6%
<29 MV/m
<2.2 MW
<2 m
FODO
Comment
H- are possible
+- 50 keV
Peak, (2.86 ms long with a repetition rate
of 14 Hz)
Transverse RMS normalized
Longitudinal RMS
Design
Above 30 MeV
1.6 Ekp
Peak, dissipated+beam load, including
Design constraint
Empty tubes for Electro Magnetic Dipoles
(EMDs) and Beam Position Monitors
(BPMs) to implement beam corrective
schemes
Lund - 2014_12_02 Audit
PMQ field
<62 T/m
Beam dynamics
Max Gradient ~61.6 T/m
FODO lattice
Uniform input distribution
∆𝜀𝑥,𝑦 = 2%, ∆𝜀𝑧 = 1%
Lund - 2014_12_02 Audit
Istituto Nazionale di Fisica Nucleare (Italy)
DTL design
Tank
1
2
3
4
5
Cells
61
34
29
26
23
E0 [MV/m]
3.00
3.16
3.07
3.04
3.13
Emax/Ek
1.55
1.55
1.55
1.55
1.55
φs [deg]
-35,-25.5
-25.5
-25.5
-25.5
-25.5
LTank [m]
7.62
7.09
7.58
7.85
7.69
RBore [mm]
10
11
11
12
12
LPMQ [mm]
50
80
80
80
80
Tun. Range [MHz]
±0.5
±0.5
±0.5
±0.5
±0.5
Q0/1.25
42512
44455
44344
43894
43415
Optimum β
2.01
2.03
2.01
1.91
1.84
Beam Det [kHz]
+2.3
+2.0
+2.0
+1.8
+1.8
Pcu [kW] (no margin)
870
862
872
901
952
Eout [MeV]
21.29
39.11
56.81
73.83
89.91
PTOT [kW]
2192
2191
2196
2189
2195
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DTL Selected technologies
• DTL normal conducting, PMQ focusing, internal BPM and steering
dipoles for orbit correction, space for additional beam
instrumentation in the tank transitions.
• With this architecture the beam dynamics is very smooth, with short
focusing period, to fulfill the emittance increase requirement.
• The mechanical stiffness and geometrical accuracy is guaranteed by
the thick stainless steel tank, and by the DT positioning system (CERN
patent).
• Key mechanical technologies
• High precision machining
• qualification of small parts, (DT) by CMM and
large pieces (tank) (laser tracker, arm..)
• E-beam welding (Zanon, CERN….)
• Vacuum brazing (in house)
• Copper-plating of large tanks (two possible providers,
CERN and GSI)
CMM machine at INFN Padova
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Mechanical Design
GIRDER (EN AW5083 Al alloy)
Precise positioning of the DT stem axis
in steel bushing SLAVE
Helicoflex
Vacuum tightness at stem/tank
interface
TANK (304L stainless steel)
internal Cu plating on finished surface internal Cu plating on finished
surface (Ra 0,8) high stiffness support MASTER
Beam pipe
Brazed joint
Rough sleeve
316LN
Sep. cylinder
304L
Rough DT body
CuC2-OFE
Lund - 2014_12_02 Audit
Steerer (cables not
represented)
DTL sub-systems and interfaces
RF SYSTEM
Control system
Diagnostic
RF network
RF window
• RF couplers
• RF pick ups
• Movable tuners and
controllers (TCP/IP prot.)
DTL
INFN
• Support
• Alignment refs
• Pumps
• Valves
• gauges
Valve
Valve
MEBT
• Local Control system
(vacuum, cooling)
• Steerer Power Supply
• Intertanks
• BPM signals
• BCT inside DTL end
flange
Spoke
section
• Water cooling skid
• Water cooling
distribution
Heat exchanger
Vacuum SYSTEM
COOLING SYSTEM
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Interfaces
1 Cooling skid with 5
three-ways valves
Vacumm manifold
Lund - 2014_12_02 Audit
Pick-up and movable tuners
RF windows and supports
Intertanks and tank covers
Prototypes and high power test
(planning and results)
Lund - 2014_12_02 Audit
PMQ
Rare earth block specifications (Sm2Co17):
-
Error Br < 3%
Error an Angle < 2deg
Dimension tolerances < 0.05mm – 0.1mm
Br=1.1 T → Simulated Gradient=65 T/m
Assembly specifications:
Goal:
-
define assembly criticalities
verify feasibility of specifications
define magnetic measurement bench and procedure
tunability of PMQ
Company qualification
Istituto Nazionale di Fisica Nucleare (Italy)
0.05
1.2
1
0.04
0.8
drift tube
PMQ
B(z) at (x,y)=(12,12)mm
B(z) at (x,y)=(1,1)mm
B(z) at (x,y)=(5,5)mm
B(z) at (x,y)=(10,10)mm
0.03
0.6
0.02
0.4
0.01
Leffective 
 B( z )dz
line
BMAX (line)
 0.046m
0.2
0
0
0
0.01
0.02
0.03
0.04
z [m]
0.05
0.06
0.07
0.08
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B [T]
-
Housing Material - Stainless Steel (316LN)
Outgassing rate per magnet below 4.10-6mbar l s-1
Gradient integral error (rms) -+ 0.5 %
Magnetic versus geometric axis: < 0.1 mm
Harmonic content at 10 mm radius: Bn/B2 for
n=3,4,...10: < 0.01
Roll: 1 mrad
radial coord.
[m]
-
PMQ
Rare earth block specifications (Sm2Co17):
-
Error Br < 3%
Error an Angle < 2deg
Dimension tolerances < 0.05mm – 0.1mm
Br=1.1 T → Simulated Gradient=65 T/m
Assembly specifications:
Goal:
-
define assembly criticalities
verify feasibility of specifications
define magnetic measurement bench and procedure
tunability of PMQ
Company qualification
Istituto Nazionale di Fisica Nucleare (Italy)
0.05
1.2
1
0.04
0.8
drift tube
PMQ
B(z) at (x,y)=(12,12)mm
B(z) at (x,y)=(1,1)mm
B(z) at (x,y)=(5,5)mm
B(z) at (x,y)=(10,10)mm
0.03
0.6
0.02
0.4
0.01
Leffective 
 B( z )dz
line
BMAX (line)
 0.046m
0.2
0
0
0
0.01
0.02
0.03
0.04
z [m]
0.05
0.06
0.07
0.08
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B [T]
-
Housing Material - Stainless Steel (316LN)
Outgassing rate per magnet below 4.10-6mbar l s-1
Gradient integral error (rms) -+ 0.5 %
Magnetic versus geometric axis: < 0.1 mm
Harmonic content at 10 mm radius: Bn/B2 for
n=3,4,...10: < 0.01
Roll: 1 mrad
radial coord.
[m]
-
Prototypes: PMQ
1.00E-03
1.00E-04
1.00E-05
Partial Pressure [mbar]
Vacuum test
- final pressure similar to the
background value.
- Larger amount of H2O, H2, O2, C02
These cannot be determined if they
are from the AISI frame or from the
PMs.
1.00E-06
Hydrogen
Helium
1.00E-07
Water
1.00E-08
Nitrogen
Oxygen
1.00E-09
Argon
Carbon Dioxide
1.00E-10
1.00E-11
1.00E-12
0
2
4
6
8
10
Time [hr]
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14
16
18
20
Prototypes: PMQ
The PMQ prototype built and
assembled at INFN-Torino has been
measured with a rotating coil at CERN
The integrated gradient is 63.7 T/m
and the harmonic content is lower
than 1% at 7.5 mm radius
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Prototypes: BPM and EBW test
• BPM: strip-line already brazed, waiting for coaxial feed-trough from USA
• Mapper at LNL
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Result of brazing and e beam welding test
•
•
•
EBW on Brazing possible weak point
(T ebw > 1100°C, Tbrazing =850 °C)
Simulation shows non problem
(Power_EBW=1800 W, v=12mm/s,
spot volume=1mm3, brazed point <
650°C)
Tests have proven vacuum tightness
and integrity (EDM slice)
ebw
brazing
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High Power test @ LNL
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•
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2 solid state amplifiers 125 kW-CW each, 352 MHz.
Control system developed for multiple coupler feeding.
Waveguides and circulator at LNL.
IFMIF high power test stand now ready will be readapted.
High power DTL prototype from Linac4-CERN (peak power 180 kW, 10% duty cycle,
E0=3.3MV/m) agreement KN2155/KT/BE/160L between CERN and INFN-LNL
3 drift tubes will be replaced by ESS drift tubes containing instrumentation + 1movable tuner
for frequency control.
Ready for test in summer 2015 (delay of 6 moths due to amplifier delivery)
Magic tee
Prototype schedule
Deliverable no.
Deliverables
Delivery Deadline
1
Design, purchasing and installation of BPM test stand at INFN-LNL.
30/10/2014
2
Prototype production of a permanent magnet quadrupole (PMQ).
Complete characterization of PMQ at CERN test bench.
30/11/2014
3
Prototype production of a BPM and Steerer to be installed in proper
DTs.
30/03/2015
3
Construction and assembly of three complete DT prototypes with
PMQ, with BPM and with steerer. Installation of DT prototypes in
Linac4 DTL prototype.
30/05/2015
4
Design and construction of a movable tuner.
31/03/2015
5
Modification of the test stand used for IFMIF in order to test ESS
components.
30/05/2015
6
Tests of DT and tuner at nominal power and duty cycle (the DTL
prototype developed by CERN and INFN-LNL will be used).
31/06/2015
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Production sequence (TBC by CDR)
1.
Forged cylinders production, tank machining, copper plating. Girder and other
components, CMM and vacuum tests…
2. Production of the beam components (PMQ, BPM, dipole steerers)
3. Production of vacuum, support and inter-tank components
4. DT Brazed structure production (with cooling circuit tested)
5. Integration of the beam component in the DT
6. E-beam welding sealing, final tests on DTs
7. Assembly of the module (2 m), installation and alignment of the DTs
8. Assembly of the tank (4 modules), alignment, machining of the adaptation rings for
relative position, tuning, tuners, ports, vacuum test,…
9. Installation and alignment of the tanks in the tunnel, installation of the intertank
plates
10. Installation of vacuum, cooling, RF couplers….
NOTE 1-6 al INFN site, 7-8 DTL workshop at Lund, 9-10 in the tunnel
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SITE REQUIREMENTS FOR DTLW
•
•
•
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The DLTW is a "clean" and quite environment, temperature controlled (+1 deg
over 30 min for bead pulling, +4 deg over the year).
About 13x 10 m is necessary for the assembly of the tank, separate space will be
used for possible storing of assembled tanks.
The DTLW should be a closed part of a larger building, or in any case there should
be a convenient entry space (for structures) before exiting outdoor (at least 10x8
m); such space can be shared with other labs; it is useful sometimes the possibility
to enter this space with small vans or tracks. A small vestibule for people (about
2x2 m) is required.
A slow crane at least 3 tons inside the workshop for the assembly of the tank is
needed.
The DTLW should be not far from the tunnel, a strategy to move the 8 tons tank
into the tunnel will be defined by ESS.
Mechanical workshop for small interventions and adjustments should be
accessible, electrical supply and compressed should be available.
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Preliminary Schedule
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2014: conceptual design
Q1 2015: completion of critical prototyping phase
April 2015 Integration on site meeting
June 2015 CDR
2015: technical design phase, detailed drawings, tender for rough
material
• 2016-2017: construction (sequence: tank 5-4-3-1-2)
• 2017-2019: assembly and tuning (sequence: tank 5-4-3-1-2)
• 2017-2018:
–
–
–
–
installation and conditioning in the tunnel of tank 5-4-3.
Installation conditioning and beam commissioning of tank 1 in the tunnel
Installation and conditioning of tank 2
beam commissioning of the 5 DTLs
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DTL organization at partner lab
• Andrea Pisent (WU coordinator, LNL)
• Francesco Grespan (deputy
coordinator, LNL)
• Paolo Mereu (Mechanics design,
Torino)
• Michele Comunian (Beam dynamics,
Torino
LNL)
• Carlo Roncolato (Vacuum system and
brazing, LNL)
• Marco Poggi (Beam instrumentation,
LNL)
• Mauro Giacchini (Local Control
System, LNL, TBD)
LNL
Bologna
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Major Procurements
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Tank forged material (stainless steel)
OFE Copper parts
Stainless steel parts
RF windows
Movable tuners
Vacuum valves
Intertank boxes
Copper plating
Tank machining
Drift Tubes machining
E-beam welding
BPM production
Steerer dipoles (design, production)
PMQ (material, machining, field test)
Supports
Cooling skid and cooling circuit components
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Top risks
• Beam performances in beam
commissioning (61 tubes in tank 1 and
final).
• DT alignment.
• DT production (QA, mainly dimensions,
vacuum and water tightness).
• Copper plating quality
• Intertank integration
• Logistics: assembly of the tank in the
DTW, transport to the tunnel…..
• RF conditioning
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Next Six Months
• CDR
• Completion of mechanical specs and production
drawings
• Completion of critical prototypes
• Forged tank procurement for the 1st module
• Launch the RF window procurement
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Summary
• The DTL is a large and complex part of the ESS linac.
Respect to the successful Linac4 DTL @ CERN we
shall have higher energy and duty cycle.
• The overall linac performances are crucially
determined by the quality of the DTL realization.
• The DTL design has been optimized for best beam
performances, the main technological choices are
been tested with prototypes.
• In June we shall have the CDR, necessary to launch
the first procurements.
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