hiradmat window design report v4.0 1michael monteil - 29 april 2010
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Michael MONTEIL - 29 April 2010 1
HiRadMat Window
Design report v4.0
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Specifications
• Interface between machine vacuum and Atmospheric pressure
10-8 mbar / Patm Protective atmosphere !!!
• Aperture min 60 mm
• Resist to a proton beam size on the window :1 s = 0.5 mm
“Beam Size at the TT66 Vacuum Window”,C. Hessler, 26.02.2010
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Headlines• Be
– PF-60– Uranium
• Maximal temperature in Be ; double-checking– Value– Criterion– Conclusions about Window Integrity
• Specifications• Final design
– Presentation – Why is the Be foil not flatter on C-C in CNGS window design ?
• Thermal shockwave effects• Price• Future tasks
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Different grades of Be
Data: Brush Wellman
Luca Bruno said : IF there is Uranium, it is anyway in very low proportion. It should not be a problem for our study.
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Be grade : PF-60
• Low rate of Beryllium oxide compare to PS-200– So higher purity
• Good quality-price ratio (Next slides…)– 1.5 to 2 time cheaper than IF-1
• Almost the same temperature distribution as pure Be and IF-1 (IF-1 a bit better…) Data V3.0
• Used in CNGS…Collaboration: J. Blanco
J. Blanco
HiRadMat Be window
• Beam parameters at the window location– 0.5mm sigma
– 450GeV
– 288 bunches * 1.7E11 p+
– 1/18 Hz.
• Temperature values
* From A. Ferrari (EUROTeV-Report-2008-009)
source method temperature [C]FLUKA Hottest spot 497FLUKA Average (1.41 sigma) 330Formula* dE/dx (conservative) 481Formula* restr. dE/dx 283
PF-60
J. Blanco
CNGS Be window
• Beam parameters at the window location– 0.53mm sigma at focal spot(not at window) -> difference from HiRadMat
– 400GeV
– 4.8E13 p+
– 1/6 Hz.
• Temperature values (errors are in the order of 3% for FLUKA)
* From A. Ferrari (EUROTeV-Report-2008-009)
source method temperature [C]FLUKA Hottest spot 422FLUKA Average (1.41 sigma) 297Formula* dE/dx (conservative) 417Formula* restr. dE/dx 247
PF-60
J. Blanco
Conclusions• The Hottest spot using the FLUKA output approach gives a very conservative value, as it
only occurs in a small region compare to the beam size.
• The analytical approach (formula):– Using dE/dx(stopping power), it gives a conservative upper limit. It doesn’t consider that a fraction
of the stopping power escapes from the window.
– The restrictive dE/dx is more realistic, as it consider that a fraction of the stopping power is not deposited in the window.
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Maximum temperature
• Maximum Value : 500°C• Criterion
– According to BW : “ Regarding the exposure of beryllium material to 500°C, please be advised that the material should survive that temperature for short periods of time ”
– According to L. Bruno, if the load is carried by the C-C, the maximal temperature is:Tmax(K) = Trecrystallization(K) = 0.5*Tmelting Point(K)
Tmax(K) = Trecrystallization(K) = 0.5*1546K = 773K = 500°C
• Conclusions : OK– Maybe beam test ?
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Design
• Specifications– Be & C-C– Aperture min. 60mm– DN63 conical plug-in flange– 15 cm depth maximum– Need to flatter Be on C-C (because of 500°C)
• Remark– Cannot machine Be at CERN
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Design• Choices
– Standard flanges only (cheaper)– Be window is assembled in lab
(safety)– Conical flange (faster assembly
once in experimental area)– Need to machine tube depending
of carbon final thickness
DesignConical Flange (plug-in flange)Tube (connection conical flange <-->
conflat flange)2 x Conflat (Window in-between)
• HiRadMat – Option 1
Design: J. Kortesmaa & M. Monteil (TE/VSC)
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CF Flange with Be foil
Data: Brush Wellman
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Why is the Be foil not flatter on C-C in CNGS window design ?
CNGS
Nota: Those drawing are drafts. Above dimensions are not representative of the reality
According to J.M. Jimenez : Main idea behind window design was to avoid “touching” the sflange from BW. JMJ agrees that HiRadMat design is better and he just noticed that we might need to machine the inner diameter of the gasket
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Few important (& positive) remarks
• Tightness of foil : Warranty by BW• Tightness between CF standard flanges :
Experimented standard assembly
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Thermal shockwave effects• Window flatter on C-C
High stiffness and also no axial displacement
So no more axial vibration mode
• Calculation (If window not flattered, so conservative)If c*t0 > r0 and r0 << R then
SigmaMax < 2*r0/(c*t0)*E*Alpha*T0
Results :Sigma < 21 MPa
Wherer0 : heated region (spot) (0.5e-3m)t0 : heating period (7.2e-6 s)C : celerity (15e3 m/s)R : radius of window (0.035 m)E : 303 GpaAlpha : 15e-6 m/m-°CT0 : Sudden temperature rise (500°C)
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CF Flange with Be foil
• Number of flange to order : 2– Spare : 1
– Window installed : 1
• Price– 1944 $ * 2 = 3888 $ Data: Brush Wellman
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To do :
• Order Beryllium– Delivery: 4 Weeks ARO for flanges (Option 1)
• Cut C-C disks– Measure thickness– Machining tube (According to calculation, deflection of
Be foil is about 0.5mm)
• Assembly• Test
– Check that Be foil is flatter on C-C
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V3.0 slides
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Solutions - Sum-up
• #1: C-C (Differential pumping)– Protective atm (Nitrogen ?)– Radiations?
• #2: C-C + Graphite foil (useless now)• #3: Tight steel “ring” with a C-C plate• #4: Beryllium
– Safety problem• #5: C-C + Beryllium
Today
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“TED @ TI2, TT40” – Beryllium version
“TED @ TI2, TT40” HiRadMat – Option 2
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“TED @ TI2, TT40” – Beryllium version
• Quote from BW
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2 design proposals
Option 1 Option 2
+ Not that much
- Precautions for the assembly- Non Standard conflat assembly
(Tightness)- Might be careful to not cut
(shear cut) the Be foil during assembly
+ Life warranty on Be + flange assembly
+ Easy to assembly+ Standard conflat assembly+ Tightness OK
- Not that muchNota: Those drawing are drafts. Above dimensions are not representative of the reality
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2 design proposalsCost estimation
Be Foil
Option 1 Option 2
• Number of foil to order : 3– Spare : 1– Window installed : 1– “In case we break a foil while
assembling” : 1
• Number of flange to order : 2– Spare : 1– Window installed : 1
Nota: Those drawing are drafts. Above dimensions are not representative of the reality
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2 design proposalsCost estimation
Be Foil
Option 1Flange
Option 2Foil
Nota: Those drawing are drafts. Above dimensions are not representative of the reality
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About thickness, how does BW design their own Be foils?
With (Thickness 0.25mm, radius 35mm, pressure 1.01 kPa, E 303Gpa, Poisson 0.08)
Results– sedge= 305MPa > 275 Mpa !!
– scenter= 297Mpa > 275 Mpa !!
Data: Brush Wellman
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However…• BW : “With confirm that your
calculations with reference to the DB450277 assembly are correct and show over the recommended values, however, the assembly was designed using empirical data as well taking into consideration the calculated values. We have performed tests on this design and found it to be reliable, with units sold to customers over the years performing well under real-life conditions.”
• Explanation– Because of plasticity effects, Be foil
withstands 1 Atm (according to BW tests) even if Roark’s calculation says that it doesn’t withstand
Data: Brush Wellman
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To know• Be have ultra high
resistance to fatigue cracking
• High endurance strength level
Data: Brush Wellman
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Solutions #5stresses and deflection - C-C+Be under DP = 1 atm
• Linear circular fixed support• 2 planes of symmetry• Geometry
– Diameter f 80 mm– Thickness: 0.254 mm– Aperture: f 60 mm
• Pressure 1 atm
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ANSYS Study - Solutions #5stresses and deflection - C-C+Be under DP = 1 atm
• Beryllium foil study– Smooth and continuous temperature distribution– Through-thickness energy deposition– Coefficient of Thermal Expansion varying with
temperature– Be (pure elasticity):
• Poisson’s ratio = 0.08• High Re = 303 Mpa
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Conclusion: influence of gap reducing
• So if we flatter the foil on the C-C, we reduce the Max stress (as shows ANSYS calculation with non plasticity model), maybe also stay in elastic domain (Bellow 275Mpa at room Temp).
We will manage to reduce this gap (flattering the Be foil as much as possible on C-C plate)
Michael MONTEIL - 29 April 2010 43
Easiness to reduce Gap C-C / Be
Option 1 Option 2
+ -
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