1 brookhaven science associates s.sharma 10/11/2006 nsls-ii mechanical subsystems accelerator...

1BROOKHAVEN SCIENCE ASSOCIATES

S.Sharma10/11/2006

NSLS-II Mechanical Subsystems

Accelerator Systems Advisory Committee Review

October 10-11, 2006

Sushil Sharma

J. Skaritka R. Alforque

C. Stelmach B. Rusthoven

W. Meng N. Simos

V. Ravindranath S. Pjerov

H. AmickS. Mason

G. Mahler


S.Sharma10/11/2006

Outline

Booster Magnets – Installation and Alignment

Storage Ring (SR) Magnets

SR Magnet- Girder Assemblies

Alignment and Installation

Vibration and Thermal Stability Issues

SR Absorbers and Scrapers


S.Sharma10/11/2006

Storage Ring Tunnel

Booster in SR tunnel

SR Beam height: 1.0 m

Beamline height: 1.4 m

SR tunnel: 3m x 2.75m


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3-D Model of the SR Tunnel

The booster follows the layout of the storage ring. There are no booster magnets over the SR straight section

The tunnel will not be too crowded due to: Low and narrow profiles of SR girders Compact designs of the front end components Small sizes of the booster magnets


S.Sharma10/11/2006

Magnet Number of magnets Length, m Strength

Dipole 60 (1 family) 1.5 0.7 T, 2.1 T/m

Quadrupole 60 (1 family)30 (1 family)6 (1 family)

0.30.30.3

9.3 T/m10 T/m<0.5 T/m

Sextupole 15 (1 family)15 (1 family)

0.20.4

200 T/m2

200 T/m2

Orbit corrector

60 (x and y) 0.2 <1 mrad

Booster MagnetsDipole

Quadrupole

SextupoleReference designs will be developed for air-cooled magnets to be hung from the ceiling of the SR tunnel.


S.Sharma10/11/2006

Booster Magnet Field Calculations

2-D field calculations were performed to verify good field regions and to ensure acceptable magnet sizes for the air-cooled magnets

Magnet Weight (kg)

Dipole 580

Quadrupole 45

Sextupole(0.4m) 55

Sextupole (0.2m) 30


S.Sharma10/11/2006

Booster Magnet Installation

The booster magnets will be installed before the SR magnets. Commercial Pallet stackers (turning radius ~ 1.5 m) can be used for lifting the magnets to required heights.


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Booster Magnet Alignment

Set-Screw Alignment Differential Truss Alignment

Different alignment mechanisms are being considered including a removable alignment mechanism consisting of jacks and translation stages.


S.Sharma10/11/2006

Number of Magnet Type Length B,B',B" Gap, Dia. Field Alignment

Magnets (m) T,T/m,T/m^2 mm Tolerance Tolerance

60 Dipole 2.62 0.4, 0, 0 60 0.01% 0.1mm, 0.5mrad

330 Quadrupole(S) 0.3 0, 21, 0 55 0.02% 0.03 mm, 0.2mrad

30 Quadrupole(L) 0.4 0, 21, 0 55 0.02% 0.03mm, 0.2mrad

30 Sextupole(L) 0.3 0 , 0 , 500 64 0.05% 0.03 mm, 0.2mrad

120 Sextupole(M) 0.25 0 , 0 , 500 64 0.05% 0.03mm, 0.2mrad

240 Sextupole(S) 0.2 0 , 0 , 500 64 0.05% 0.03mm, 0.2mrad

180 H&V&SQ Corrector 0.15 0.08,36,0 0.1mm, 0.2mrad

30 H Correctors 0.15 0.08, 0, 0

< 104 Fast H&V Corrector 0.15 0.01,0.01

90 Magnet Girders 0.1 mm, 0.5mrad

Storage Ring Magnets

The dipole gap was increased from 35 mm to 60 mm to accommodate larger vacuum chambers for the IR beamlines.


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Dipole Sextupole

SR Magnets

Quadrupole

Reference designs are being developed to meet the field quality requirements, stability and chamber geometry constraints.

R = 20 mm


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Precise Magnet Alignment by Vibrating Wire

Procedure

Support magnets on temporary support brackets resting on cam movers (or X-Y translation stages)

Align all components (magnets, chamber, wire) by a laser tracker to within 100 μm.

Align for roll angle using inclinometers and cam movers.

Adjust vertical position of the wire for the specific magnet to be aligned.

Align and lock the magnet. Remove temporary supports.


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SPring-8 Alignment

Positioning and Alignment of the SR Magnet-Girder Assembly

Positioning by Air Pads (IHEP)The magnet-girder assemblies in the tunnel will be transported by a tug transporter.

The assemblies will be positioned on removable alignment mechanisms (not shown) using air pads. Threaded rods on each side of the girder are to be in their respective slots.

After final alignment with a laser tracker, double nuts with spherical washers will be tightened on the threaded rods.


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Vibration - Ambient Ground Motion

At the CFN floor rms (2-50 Hz) horizontal and vertical displacements are 30nm and 32 nm, respectively. The CFN concrete floor thickness is 16-24 inch.

Vertical Displacement

Magnet stability tolerances (S. Kramer)Random motion, rms (dx,dy) < (330nm, 23nm)


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PSDs of Vertical Ambient Motions at Light Sources

Additional site vibration measurements are planned to verify present results and to identify local sources of excitation in and around the NSLS building.


S.Sharma10/11/2006

Magnet Vibration due to Ambient Ground Motion

Ambient ground motion drops steeply as 1/ω4

No significant vibration amplification for ω/ωn << 1 First natural frequency of the girder-magnet assembly should be above 30 Hz.

Seryi [2003]


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Natural Frequencies and Mode ShapesSR Magnet–Girder Assembly

Rolling Mode, f1 = 68.7 Hz Twisting Mode, f2 = 94.3 Hz

Bending Mode, f3 = 139.7 Hz


S.Sharma10/11/2006

Thermal Stability

Air and process water temperature regulation: ± 0.1ºC

α (expansion coefficient). L (beam height). ΔT (change in temperature)

12(μm/m.ºC) . 1 (m) (± 0.1 ºC) ═ ± 1.2 μm

Magnet Stability Requirements are presented by S. Kramer.

Air-conditioning ducts from a single mechanical room will cover 6 cells (130m). Therefore, magnet stability tolerance limit for a plane wave of < 3 Hz ( wavelength ~ 100M) can be used:

RMS vertical displacement of the quadrupoles < ± 2μm


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Thermally-Insulated NSRRC Girder

Thermal Stability (Contd.)

LCLS Support Stand

If necessary, the girders can be insulated to reduce ΔT by a factor of ~ 2.


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SR Absorbers

Chamber 2

Counter-Flow Absorber Flange AbsorberCrotch Absorber

Ray-Tracing

RF Spring


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SR Crotch Absorber – FE Thermal Analysis

The crotch absorber intercepts 814 W at a normal peak power density of 0.25kW/mm2.

A maximum temperature of 104.5 ºC is calculated.


S.Sharma10/11/2006

SR Wiggler Absorber

Wiggler Absorber

The wiggler absorber clips the radiation fan by about 1 mrad on each side to shadow the downstream exit port. The total intercepted power is 11.6 kW out of 64.6 kW.

The absorber is cantilevered from the upstream flange to allow thermal expansion during bakeout.

Glidcop


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Maximum temperature (ºC)

397

Cooling wall temperature (ºC)

187

Maximum von Mises stress (MPa)

427

SR Wiggler Absorber – FE Thermal Analysis

About 15 - 20% of the incident power is reflected or scattered. Therefore, the maximum surface temperature is expected to be less than 337ºC.


S.Sharma10/11/2006

Thermal Fatigue Tests at APS (26-ID Beamline)

Beam

StepperMotor

GlidcopSamples

Cooling Tubes

Beam

StepperMotor

GlidcopSamples

Cooling Tubes

Realistic design criteria have been established based on thermal fatigue tests at ESRF and APS:

For Glidcop intercepting an ID beam, thermal fatigue life at 400ºC is estimated to be > 30,000 cycles.


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Tentative Locations of the Scrapers: One horizontal scraper (HS-A) in the dispersive section to

acquire energy distribution of the electron beam. This scraper may have only one (inboard) blade.

One horizontal scraper (HS) in a straight section with zero dispersion in order to have information on the transverse size of the electron beam

Two vertical scrapers (one upstream of the injection straight and another downstream of it) to shadow ID poles from electro-magnetic shower.

SR Beam Scrapers

HS-A

HS

VS (1)VS (-1)


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SR Beam Scrapers - Design

Vertical Beam Scrapers Beam Scrapers with Large Blades

Studies are underway to find the best available locations for the scrapers and to optimize their blade geometry. Their role in protecting the ID magnetic structures will be investigated.


S.Sharma10/11/2006

Concluding Remarks

Reference designs are being developed for the booster and SR magnets that will meet field requirements, stability and geometry constraints.

A vibrating wire technique will be used to meet the precise (30 μm) alignment tolerance for SR magnets. An R&D program will be initiated to design and test the alignment hardware/software.

The design of SR magnet-girder assemblies will ensure that vibration stability requirement will be easily met. Thermal stability requirements are likely to be met with the tunnel air temperature control of ± 0.1ºC.

Conceptual designs of the SR wiggler and crotch absorbers have been developed.

Beam scrapers are being investigated for their optimum locations and designs, and for their contribution towards protecting IDs from EM shower.

1 brookhaven science associates s.sharma 10/11/2006 nsls-ii mechanical subsystems accelerator...

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