1. THE NEW FAST WIRE SCANNER DESIGN FOR THE PSB
Dmitry Gudkov
Mechanical Engineer
Beam Instrumentation Group - Mechanics and Logistics Section
In close collaboration with:
William Andreazza, Jose Luis Sirvent Blasco, Nicolas Chritin, Bernd Dehning, Jonathan Emery, Paolo Magagnin, Emilien Rigutto, Ray Veness
BI Day, 10th of March 2016
BI Day 10 March 2016

2. Contents Beam wire scanner PS Booster Fast wire scanners at CERN
New fast wire scanner for PSB
Engineering design of new fast wire scanner for PSB
Shaft Angular Position Measurements. Optical Position Sensor
Signal acquisition
Control and Acquisition electronics
Status / Planning
Summary
BI Day 10 March 2016

3. Control and acquisition
Beam wire scanner
Particles generated by the interaction wire - beam
Thin carbon wire passes through the particle beam (one out-scan and one in-scan) with linear speed of 20 m/s.
Shower of secondary particles is created.
Scintillator measures the flux of particles scattered by the interaction of beam and wire.
Acquired data is combined with the wire position during the course of the scan.
Transverse beam profile is reconstructed.
BEAM
Vacuum Pipe
Scintillator
Control and acquisition
electronics
Optical filters
PM current
Fork
position
Photomultiplier
Preamplifier
BWS system can be divided in three main units: wire moving mechanism in vacuum, detector and control and acquisition
Example of beam transversal profile
By courtesy of J. Emery
More details on next slides
BI Day 10 March 2016

4. PS Booster First beams on 26 May 1972 4 superimposed synchrotron rings
Radius 25 m (1/4 of PS)
Receive beams of protons from the linear accelerator LINAC 2 at 50 MeV and accelerate them to 1.4 GeV for injection into the Proton Synchrotron (PS).
PSB allows the PS to accept over 100 times more protons
Picture from
Picture from
Picture from
BI Day 10 March 2016

5. Fast Wire Scanners at CERN
Wire scanners currently in use
SPS BWS Prototype (2014)
motor which is mounted outside the vacuum pipe
motion is then transmitted through bellows
inaccuracies due to the relatively complex mechanics
motor with vacuum compatible rotor
no bellows
two supports for the shaft which leads to drum-based design, complicated and expensive for production
BI Day 10 March 2016

6. New Fast Wire Scanners for LIU Program at CERN
The fast wire scanner for PSB is a part of LIU program requiring more accurate and faster wire scanners:
Plan is to have one design for all the machines.
Total 18 scanners will be needed.
The machines: PS, PSB, SPS.
Installation of 18x instruments is planned for LS2.
(B. Dehning: “Specifications and Planning for future wire scanners at CERN”, BWS design review, )

7. New fast wire scanner for PSB
Comparison with previous Beam Wire Scanners:
Direct drive (no bellows used)
Compactness
biggest vacuum flange CF273 (CF400 for SPS type)
Weight
17 kg kinematic assembly (SPS type ~40 kg)
23 kg tank (SPS type ~50 kg)
No optical fibers or lenses inside vacuum volume
First Prototype in the PSB
PSB 4L1
CDD: PSBBWSRA0001
Courtesy of N. Chritin
BI Day 10 March 2016

8. New fast wire scanner for PSB. Engineering Design
Motor selection
Parameter
Value
Motor type
Frameless PMSM
Rotor core material
Steel
Permanent magnets material
Sm2Co17
Wire linear speed, m/s 20
Angular speed, rad/s
133
Acceleration, rad/s2
15711
Inertia of the load, kg x m2
1.1E-03*
Radial air gap (stator ID – rotor ED), mm
0.7
Ionizing radiation dose, kGy/year 1
Acceleration profile
New motor will be the same in beam wire scanners for PS/SPS/PSB so should provide torque sufficient to accelerate the wire to linear speed 20 m/s in both configurations: mm (PS/SPS) and 150 mm (PSB) mm forks;
The desired motor should be based on the standard market solution which will be available for many years;
The rotor will be located in vacuum and must be vacuum compatible; the use of any glue, other adhesives or insulating materials is not possible. Solid core rotor should be used.
The moment of inertia of the rotor should be minimized in order to reduce the required acceleration torque;
Features for mounting the rotor on the shaft (key-slots, holes, etc.) should be considered in the design;
*-values are optimized during the mechanical design phase
BI Day 10 March 2016

9. New fast wire scanner for PSB. Engineering Design
Motor selection
Torque required for acceleration of the wire scanner forks in order to achieve the velocity of 20 m/sec on the distance of 60⁰ ( 𝝅 𝟑 )
As a baseline the ALXION 145STK2M-1500 was chosen
Peak torque, N.m 55
Rotor Inertia, kg.m^2
1.28E-03
Fork length:
R = mm
Calculation of Required Torque
𝑇=𝐽×𝛼= 1.1𝐸−03+𝐼𝑟 𝑘𝑔. 𝑚 2 × 𝑚 𝑠 2 =
= 37.5 N.m (68% of peak torque)
Special vacuum compatible version of rotor is developed
J – inertia of the load + inertia of the motor rotor
Status: delivered at CERN, under validation
BI Day 10 March 2016

10. New fast wire scanner for PSB. Engineering Design
The kinematic subassembly unit is designed so that it can be integrated in the following machines: PS, SPS, PSB
First prototype will be installed in PSB Sector 4L1 line 3
Beam scans in horizontal plane
Kinematic unit – vacuum tank interface (CF273)
Viewport interface (CF100)
Vacuum pump interface (CF100)
RF diagnostics feedthrough interface (CF40/QCF40)
Beam Pipe interconnections – conical flanges ø195 mm
conical flanges ø195 mm
Vacuum pump interface (CF100)
RF diagnostics feedthrough interface (CF40/QCF40)
Kinematic unit – vacuum tank interface (CF273)
Viewport interface (CF100)
BI Day 10 March 2016

11. New fast wire scanner for PSB. Engineering Design
Magnetic Brake
Motor Stator
Fork
Wire
Viewport
2 possible “home” angular shaft positions
Resolver
Used to measure angular position of the shaft
Shaft
Wire diagnostics feedthrough
Encoder Disk
Encoder disk protection
Vacuum chamber
Motor rotor
BI Day 10 March 2016

12. New fast wire scanner for PSB. Engineering Design
Copper interface
Ceramic insulator
Wire diagnostics feedthrough
2 x ½ flanges with tapped holes
2 x ½ ring
Feedthrough HOSITRAD H100150
MACOR Connector
BI Day 10 March 2016

13. New fast wire scanner for PSB. Engineering Design
Stepped Vacuum Chamber
CDD: PSBBWSRA0025
The component consists of 3 main parts forming the vacuum volume and 4 optical tube interfaces
All the parts except 4 optical tube interfaces are welded together with use of “511” Electron beam welding from vacuum side with full penetration
4 optical tube interfaces are welded with use of “511” Electron beam welding from outside with full penetration
Blank: 316LN 3D forged 2
Electron beam welding (full penetration)
Wall thickness 0.3 mm
Wall thickness 0.3 mm
Wall thickness 0.4 mm 3
Electron beam welding (full penetration) 2 2 3
BI Day 10 March 2016

14. New fast wire scanner for PSB. Engineering Design
Resolving potential trapped volumes (virtual leaks)
Approved by TE-VSC
Hole on the shaft
Slot on shaft
Slot on the washer
Hole on the shaft
Slot
Hole
Hole on the shaft
Vented Screw
Washer with slot
Slot
BI Day 10 March 2016

15. New fast wire scanner for PSB. Engineering Design
Vacuum Tank 2
Two side face parts are welded with use of “51” electron beam welding process (from outside)
Interfaces tubes and flanges are welded with use of “14” Gas-shielded welding with non consumable electrode from inside or outside with full penetration 2
Electron beam welding (full penetration) 1 2 2 1 2 2 1
CDD: PSBBWSRA0006 2
BI Day 10 March 2016

16. Shaft Angular Position Measurements. Optical Position Sensor
1310nm continuous wave laser located on the surface
Lens detector system, located in the tunnel (link of Single Mode Optical Fibre)
Encoder disk (located in vacuum), contain a track, around its circumference, with a pattern of alternated reflective/non reflective slits
UHV viewport
Focused spot of light of 20um
Optical system is able to recover the reflections produced by the slits and couple it back to the fibre optic
Reflections are sent back to the surface and directed to the system photodiode (thanks to the optical circulator)
By courtesy of J.L. Silvent Blasco
BI Day 10 March 2016

17. Shaft Angular Position Measurements. Optical Position Sensor
Optical disk made of Aluminium for lower inertia
Slits made by laser engraving
Lens system and optical fiber are located outside the vacuum volume
Focal distance adjustment possibility by means of fine pitch thread
Bakable up to 200 ⁰C
Very good roughness is required on the encoder disk face: Ra0.025
BI Day 10 March 2016

18. pCVD Diamond detector–based secondary shower acquisition system
Signal acquisition
Scintillators + PMT’s detector–based secondary shower acquisition system
pCVD Diamond detector–based secondary shower acquisition system
Scintillator
Filters
PMT
Preamplifier
Charged particles hit the Scintillator located downstream the BWS tank
Photons are generated by scintillator material
Photon fluency attenuated by filters and transformed into electric current by photomultiplier tube (PMT)
Pre-amplifiers (I-V) for transport through long cables
Adjustable PMT and 8 Optical filters.
Charged particles hit the gold coated diamond plate located downstream the BWS tank
Generation of mobile charges e-h
Electrical current when applying HV (Proportional to the Energy)
Compact solution (1 cm^2)
By courtesy of J. Emery and J.L. Silvent Blasco
BI Day 10 March 2016

19. Control and Acquisition electronics
Ethernet
Motor feedback into FPGA
“Intelligent drive” Scanner control, monitoring and supplies
Acquisition and supervision (VME)
CPU
TIMING
HV CTRL
Wire diagnostics
Optical encoder interface
Optical encoder interface
Long range resolver interface
Fast integration secondary shower
3-phases PWM
Control and wire electronics Physical implementation
Secondary particles shower acquisition
By courtesy of J. Emery
BI Day 10 March 2016

20. Status / Planning
All the drawings for main parts are released except assemblies
Job request submitted, fabrication planned to be finalized by summer 2016
After fabrication is completed 3 kinematic units will be assembled + 2 vacuum tanks
Fabrication starts in March 2016
BI Day 10 March 2016

21. Summary Design of the new fast wire scanner for PSB is completed
Data from fast wire scanner prototype for SPS is used
Advantages comparing to prototype for SPS (cantilevered shaft, no drum)
More compact design comparing to SPS FWS
Less components in vacuum (thanks to lens system outside the tank)
Cheaper in production than SPS FWS
Production is expected to be finalized by August-September 2016
Assembly and tests are expected in October-November 2016
Installation during EYETS
BI Day 10 March 2016

22. Thank you very much for your attention!
BI Day 10 March 2016

23. Extra slides
BI Day 10 March 2016

24. Optimization of parts. Shaft
Criteria:
Taking into account distance between forks, the maximum allowable offset is µm.
This offset is the combination of torsion, flexion and rigid body. motion of the shaft due to the radial internal clearance of the upper bearing.
Shaft movement due to rigid body motion: 𝑒 𝑃𝑆𝐵 = 4.4 µm (value based on bearings data).
Envelope for torsion and bending: = 12.5 µm.
Analytical pre-dimensioning is performed (XLS), thickness values are analysed in different shaft fractions
3D model created and analysed in Ansys Workbench
Region of interest around the wire centre ±20 [mm]
Fork
Wire
Analysis results
Flexion: 4.3 µm
Rotation between forks: 4.27E-5 rad  corresponding to 7.7 µm offset
=8.9 µm < 12.5 µm
Acceptable deformation
J shaft = 5.43 E-4 kg*m2
By courtesy of P. Magagnin
BI Day 10 March 2016

25. BI Day 10 March 2016

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27. New fast wire scanner for LIU. Series production Planning

28. Control and Acquisition electronics
SFP Ethernet
“Intelligent drive” Scanner control, monitoring and supplies
Motor feedback into FPGA
Acquisition and supervision (VME)
CPU
T IMING
BST receiver HV
CTRL
SFP Optical link
Wire resistivity & Strain gauge
External temperature and vibration
Optical encoder interface
Optical encoder interface
Long range resolver interface
Fast integration secondary shower
Magnetic brake
3-phases PWM
Control and wire electronics Physical implementation
Secondary particles shower acquisition
Electronics for the BWS SPS BI-TB

29. BE-BI-BL Jose Luis Sirvent Blasco (jsirvent@cern.ch)
5. Comparison with operational system: 3.1 LHC_Pilot 1.1e11 PpB 450 GeV (2015_10_23)
BE-BI-BL Jose Luis Sirvent Blasco
BI Day 10 March 2016