CERN New wire scanner technology at - CERN Indico
←
→
Page content transcription
If your browser does not render page correctly, please read the page content below
New wire
scanner
technology at
CERN
W.Andreazza 21/6/2021 1
Summary
• A wire scanner in a nutshell
• CERN wire scanners and reason to change
• A challenging concept
• Direct drive system
• Wire scanner motor
• Optical encoder
• Thin wall stepped chamber
• Metal 3D additive machining forks
• Control system and electronic
• Conclusions
W.Andreazza 21/6/2021 2
A wire scanner in a nutshell W.Andreazza 21/6/2021 3
CERN wire scanners and reason to change
• 32 beam wire scanners installed all along the accelerators
• These instruments are used on daily basis to assess the
characteristics of the beams and cumulate several thousands of
scans every year
• A new generation of the wire scanners has been developed and
produced as part of the LCH Injector Upgrade(LIU) project to
comply with new and more stringent specification:
Wide range of measuring speed(5m/s to 20m/s)
Position measurement accuracy in the order of 1 μm
Improved reliability
Improved control and readout system
Ultra High Vacuum compatible
One type of instrument for three different machines
W.Andreazza 21/6/2021 4
A challenging concept was developed Direct drive system: all the key components
and designed to achieve the required mounted together on the same shaft
performance
Vacuum compatible motor with
the rotor installed in vacuum Thin wall stepped chamber to
hold the in-air components and
embed the in-vacuum parts
Optical encoder based on
a reflective disk engraved
with anti-reflective marks
Metal 3D additive machining forks
W.Andreazza 21/6/2021 5
Direct drive system
All the movable parts are
under vacuum and mounted on
the same shaft
Suppression of the
kinematic links with the
elimination of the mechanical
play
Improvement of the wire
position control yielding
enhanced accuracy and
precision
W.Andreazza 21/6/2021 6
Wire scanner motor
Ultra high vacuum compatible
frameless electrical motor
The stator is mounted in the air when
the fully compatible rotor is under
vacuum
Selection of the motor driven by its
nominal torque, overall dimension and
vacuum compatibility
Rotor magnets hold with shrink fitted
banding to avoid any use of glue(not
UHV compatible)
W.Andreazza 21/6/2021 7
Optical encoder
The wire position determination is done with an optical encoder based on a reflective
disk engraved with anti-reflective marks.
Very stringent requirements in term of runout(20µm) and roughness(Rt 0.02)
Marks width 6µm with a pitch of 40µm
Selection of the best alloy based on mechanical properties and corrosion resistance to
fulfil the fabrication specification, RSA6061 and RSA905 were chosen
High precision machining with modern CNC modern tools required, research of the best
supplier among the member states in collaboration with EN/MME
W.Andreazza 21/6/2021 8
Thin wall stepped chamber
Wire scanner backbone component
Multistage electron beam welded ultra high vacuum flange
Two thin walls components(0.4 mm) to allow the motor and the resolver to
correctly work(air gap)
High precision machining requirement to achieve the nominal accuracy
W.Andreazza 21/6/2021
9
Metal 3D additive machining forks
Key component subjected to very high stress,
wire accelerated up to 20m/s in 1/8 of a rotation
with a peak acceleration of 15600 rad.s-2
Optimised fork design needed that requires high
stiffness in two planes and low inertia to
minimise motor torque requirements.
3D additive machining technology selected as the
best solution to produce these components.
More details in a dedicated talk will be given by
A.Miarnau
W.Andreazza 21/6/2021 10LIU Beam Wire Scanner architecture
Intelligent Acquisition &
drive crate Supervision crate
Position (Resolver) (IDC)
Power C
C
A
T H
P D
R V
U C
V
Ethernet
Position(Optica
l)
Scintillator
4x signal PMTs
Lamp test + supplies
PMT supply
W.Andreazza 21/6/2021 11
Courtesy of J.EmeryConclusions
• Extensive test campaign to validate all the key components with prototype installed in
two accelerators and reliability test in the lab(more than 100K scans nonstop)
• 25 wire scanners built, tested and commissioned.
• 17 wire scanners installed in the PS, PSB and SPS accelerators
• 6 wire scanners delivered to ESS(European spallation source, Lund, Sweden) as part of
collaboration between ESS and CERN.
• Very demanding and stringent specification fulfilled.
• Improved measurement quality, better reliability and extended lifetime.
• One type of instrument for three different machines.
What’s next
Research and studies on the type of material to use for the wire(see A.Mariet
presentation)
Development of a braiding machine for the carbon wire production
Feasibility studies on going to install the same type of wire scanner in the LHC
W.Andreazza 21/6/2021 12W.Andreazza 21/6/2021 13
W.Andreazza 21/6/2021 14
A special thanks to all my
colleagues who made this possible
Thanks for your attention
W.Andreazza 21/6/2021 15W.Andreazza 21/6/2021 16
LIU-BWS Intelligent Drive Crate (IDC)
6U, ≈ 22Kg
BWSMIB
Motion Inverter Board
EDA-03519
EDA-03634
DC-BUS Capacitor
BWSMCU Output filter “sinus”
BWSCPC
Motion Control Unit
Capacitor Power Charger
EDA-03697
EDA-03592
W.Andreazza 21/6/2021 17You can also read
