hiradmat window design report v4.0 1michael monteil - 29 april 2010

Michael MONTEIL - 29 April 2010 1

HiRadMat Window

Design report v4.0


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


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


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.


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.


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 ?


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


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)


CF Flange with Be foil

Data: Brush Wellman


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


Few important (& positive) remarks

• Tightness of foil : Warranty by BW• Tightness between CF standard flanges :

Experimented standard assembly


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)


CF Flange with Be foil

• Number of flange to order : 2– Spare : 1

– Window installed : 1

• Price– 1944 $ * 2 = 3888 $ Data: Brush Wellman


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


V3.0 slides


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


“TED @ TI2, TT40” – Beryllium version

“TED @ TI2, TT40” HiRadMat – Option 2


“TED @ TI2, TT40” – Beryllium version

• Quote from BW


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


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



2 design proposalsCost estimation

Be Foil

Option 1Flange

Option 2Foil



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


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


To know• Be have ultra high

resistance to fatigue cracking

• High endurance strength level

Data: Brush Wellman


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


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


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)


Easiness to reduce Gap C-C / Be

Option 1 Option 2

+ -

hiradmat window design report v4.0 1michael monteil - 29 april 2010

Documents

cc aperture

cngs window design

cngs michael monteil

monteil tevsc slide

blanco slide

window location

c conclusions

cern michael monteil