Overview Dave Pushka Mu2e Muon Beamline Vacuum Level 3 Manager 9 - - PowerPoint PPT Presentation

Mu2e Muon Beamline Vacuum Overview

Dave Pushka Mu2e Muon Beamline Vacuum Level 3 Manager 9 Feb 2017

Outline of Items Covered in this Review Presentation:

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• Orientation

– Key Requirements – Overview of the Geography of the Production Solenoid (PS) and Detector Solenoid (DS) and the Transport Solenoid (TSu and TSd) – Piping and Instrumentation Diagram (P&ID)

• Outgassing Methodology & Gas Load Summations for upstream muon beamline vacuum

volume and downstream muon beamline vacuum volumes

– Pie Charts of Gas Loads for upstream and downstream volumes – What is missing from the Outgassing Summation?

• Hand Calculations for upstream and downstream muon beamline vacuum volumes
• MOLFLO+ methodology

– MOLFLO+ Results for the Upstream MB vacuum volume (a.k.a PS + TSu) – MOLFLO+ Results for the Downstream MB vacuum volume (a.k.a TSd + DS)

• Interfaces and Physical Equipment Arrangement (locations of vacuum pumps).
• Schedule Slide
• Initial Evacuation

– Simultaneous Initial Evacuation of the upstream and downstream MB vacuum volumes

• Contamination and Diffusion Pump Oil
• Vessels and Safety Conformance
• Thin Windows
• Interlocks, FEMA
• Repressurization
• Back-Up Material (FEM Risk Assessment, Key Outgassing Rates, Catalog Cuts,

Performance Curves)

Requirement Document and Summary of the Requirements:

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• Mu2e docdb document 1481 provides the requirements for the muon

beam line vacuum, which include the key items:

• Required pressure levesl:

– PS + TSu (Upstream); ≤1 x 10-5 torr. – TSd + DS (Downstream); ≤1 x 10-4 torr (assuming the tracker and calorimeter achieve their gas load requirements)

• Required vacuum pump down time:

– ~ 100 hours.

• Required pre-operational cleanliness:

– standard high vacuum cleaning and degreasing.

• Required operational cleanliness:

– minimize, but not eliminate vacuum pump oil back-streaming.

Over View of the Geography:

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Mu2e 0,0,0 & pbar window Upstream Vacuum Downstream Vacuum Upstream vacuum pumps

Downstream Vacuum Pumps

Over View of the Geography:

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Hardware Deliverables for Muon Beamline Vacuum:

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Vacuum Pump Spool Piece, VPSP Instrumentation Feed Through Bulkhead, IFB Vacuum By-Pass Line Production Solenoid End Cap And High Vacuum Pump out Line Mechanical Roughing & Backing Pump Mechanical Roughing & Backing Pump

Context Material - Mu2e & Past Large Vacuum Experience:

Mu2e Verses Previous Systems Goal Actual Material Year Vol Vol Pressure Pressure ft3 liters torr torr KTeV 1994 5,500 155,742 1 x 10-4 1 x 10-6 painted C.S. NuMI Decay Pipe 2004 73,467 2,120,575 1 torr < 1 torr Rusty primed C. S. Mu2e PS 2020 424 11,993 1 x 10-5 TBD 316L Mu2e DS 2020 1,321 37,378 1 x 10-4 TBD 316L Grumman BSTS 1990 2,674 75,705 2 x 10-7 6 x 10-8 304 White Sands 1987 65,450 1,853,330 2 x 10-6 8 x 10-7 304

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Details of the View of the Areas in the Upstream (PS+TSu):

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Pump out Line Bore PS-TS and TS-TS Interface Area COL 1 and 3u

Details of the View of the Areas in the Downstream (TSd+DS) Vacuum Volume:

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Detector Solenoid VPSP IFB Col 5 TSd Col3

Muon Beam Stop Tracker, Calorimeter, Absorbers not shown, but estimates of gas loads are used in MOLFLO+ model

Piping And Instrumentation Diagram (P&ID) from 6489:

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Outgassing and Vacuum Calculation Methodology:

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• Sum up the surface areas exposed to muon beamline vacuum
• Assign material (SS, Al, Ti, W, fiberglass tape, etc)
• Estimate temperature.
• Assign outgassing rate for temperature at time = 1hour, 10 hours, etc.

– Using achievable surface conditions – For example, the HRS is not likely to be ultra sonically washed, dried, baked and never touched by human hands again

• Calculate gas load, Q = outgassing rate * area for various times
• Determine pressure ignoring geometry (1 large volume) P=Q/S
• Assign Outgassing to model in MOLFLO+ such that the total gas load

matches the sum of the Area* Outgassing Rate for the real volume. – MOLFLO+ Surface areas are smaller than actual areas, but cross sectional areas are very similar.

• Determine pressure as a function of location.

Outgassing Gas Load Values:

• Have reasonable outgassing numbers for everything in the PS+TSu.
• Have reasonable outgassing numbers for surfaces and materials in the

TSd+DS with the except of the Tracker and Calorimeter and the associated cabling and services.

– For the tracker, the requirement on the gas load is ≤0.08 torr-l/s, and that is the value adopted for this analysis

• Solid Model for Tracker is available and has been checked w.r.t. the requirement

document values

– For the calorimeter, an estimate of the outgassing load has been extracted based upon the surface area and materials expected in the calorimeter

• The details of the calorimeter are still being refined
• The long term gas load of the calorimeter is required to be negligible compared to

the tracker gas load requirement of ≤0.08 torr-l/s

• Outgassing rates come from literature (Elsey, Dayton, Santler, etc.) See

the next few slides:

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Outgassing Summations for the Upstream Volume (Spread sheet on docdb document 6470):

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PS Vacuum:

contributes to

• utgassing

Outgassing Area temperature material 10 hour

• utgassing rate

10 hour gas load PS DP Tee Section Y 17,866 25 316L 2.10E-08 3.75E-04 24 inch vacuum pipe: Y 48,192 25 316L 2.10E-08 1.01E-03 end cap truncated cone Y 55,824 35 316L 2.10E-08 1.17E-03 end cap vacuum pumpout nozzle Y 6,004 35 316L 2.10E-08 1.26E-04 End cap head Y 44,887 40 316L 2.10E-08 9.43E-04 end cap center port truncated cone Y 11,732 60 316L 2.10E-08 2.46E-04 end cap center port cylinder Y 4,775 60 316L 2.10E-08 1.00E-04 end cap beam exit nozzle Y 7,388 60 316L 2.10E-08 1.55E-04 end cap extinction nozzle Y 3,234 60 316L 2.10E-08 6.79E-05 Center Port Window Y 2,027 60 Ti 4.00E-09 8.11E-06 Beam Exit Window Y 507 60 Ti 4.00E-09 2.03E-06 Extinction Window Y 182 60 Ti 4.00E-09 7.30E-07 Primary beam entrance window by PS Y HRS cone Y 38,022 50 316L 2.10E-08 7.98E-04 HRS bore Y 31,233 60 316L 2.10E-08 6.56E-04 target Y 59 1500 W 2.00E-07 1.19E-05 target support ring Y 911 60 Al 1.10E-07 1.00E-04 target support wires Y 57 600 W 1.00E-07 5.65E-06 primary beam pipe in HRS Y 4,907 30 316L 2.10E-08 1.03E-04 primary beam pipe in TSU Y 6,193 30 316L 2.10E-08 1.30E-04 antiproton absorber Y 1,924 30 Al 1.10E-07 2.12E-04 HRS d.s. end Y 15,088 30 316L 2.10E-08 3.17E-04 HRS d.s. single convolute bellow Y 16,198 30 316L 2.10E-08 3.40E-04 HRS bellow radial plate Y 4,398 30 316L 2.10E-08 9.24E-05 P.S. d.s. end in vacuum Y 8,233 30 316L 2.10E-08 1.73E-04 PS d.s. end to bellows horz cyl Y 14,019 30 316L 2.10E-08 2.94E-04 PS to Tsu bellows Y 61,928 30 316L 2.10E-08 1.30E-03 TSU u.s. ring from bellows Y 5,341 30 316L 2.10E-08 1.12E-04

Outgassing Summations for the Downstream Volume (Spread sheet on docdb document 6470):

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DS Vacuum:

Contributes to Outgassing Outgassing Area temperature material 10 hour

• utgassing

rate 10 hour gas load cm^2 C torr-liters /s-cm2 torr-liters/s IFB shell, F10017417 Y 32,288 30 316L 2.10E-08 6.78E-04 VPSP, F10034792 Y 130,473 30 316L 2.10E-08 2.74E-03 VPSP rails Y 8,704 30 316L 2.10E-08 1.83E-04 VPSP D.S. Face at IFB Y 1,912 30 316L 2.10E-08 4.01E-05 DS Stub extension, FC0043184 Y 7,282 30 316L 2.10E-08 1.53E-04 DS Inner wall, F10005007 Y 645,849 30 316L 2.10E-08 1.36E-02 Bellows Closure Ring Y 3,809 30 316L 2.10E-08 8.00E-05 TSd - DS Bellow Y 60,479 30 316L 2.10E-08 1.27E-03 TSd O.D at DS Y 57,540 30 316L 2.10E-08 1.21E-03 TSd D.S. Face Y 18,776 30 316L 2.10E-08 3.94E-04 TSd Bore Y 106,725 30 316L 2.10E-08 2.24E-03 TSd Vertical U.S. Face Y 18,568 30 316L 2.10E-08 3.90E-04 TSd Bellows at COL3b Y 60,569 30 316L 2.10E-08 1.27E-03 TSd Bellows closure ring at COL3b Y 5,520 30 316L 2.10E-08 1.16E-04 TSd O.D at COL 3 Y 16,293 30 316L 2.10E-08 3.42E-04 Col 3b (assume = Col 3a from PS)

Sources of Upstream (PS+TSu) Outgassing Gas Loads:

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27.86%, SS bore gas load 22.76%, Pump Out Line gas load 3.25%, Window Gas Load 14.29%, Collimator Gas Load 29.78%, TS-PS interface area gas load 2.07%, target and absorber gas load

Upstream (PS+TSu) Vacuum Gas Load Sources at 10 hours

SS bore gas load Pump Out Line gas load Window Gas Load Collimator Gas Load TS-PS interface area gas load target and absorber gas load

Total Gas Load from Outgassing (torr-l/s): SS bore gas load Pump Out Line gas load Window Gas Load Collimato r Gas Load TS-PS interface area gas load target and absorber gas load 4.44E-03 3.63E-03 5.18E-04 2.28E-03 4.75E-03 3.29E-04

Sources of Downstream (TSd+DS) Outgassing Gas Loads:

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SS bore gas load 1.74E-02 5% TS-DS interface area gas load 7.31E-03 2% Feed Thru Gas Load 0% Colimator Gas Load 2.28E-03 1% IPA, OPA a,d Absorber 3.03E-02 10% Tracker 8.00E-02 25% Calorimeter 5.89E-02 18% MBS 3.19E-02 10% Bore Heaters 1.29E-02 4% unallocated 7.90E-02 25%

Downstream (TSd+DS) Vacuum Gas Load Sources Identified loads = 0.24 torr-l/s @ 10 hours and Total loads = 0.32 torr-l/s

SS bore gas load 1.74E-02 TS-DS interface area gas load 7.31E-03 Feed Thru Gas Load 0 Colimator Gas Load 2.28E-03 IPA, OPA a,d Absorber 3.03E-02 Tracker 8.00E-02 Calorimeter 5.89E-02 MBS 3.19E-02 Bore Heaters 1.29E-02 unallocated 7.90E-02

Hand Calculation Upstream (PS+TSu):

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• Requirement document; P = 1 x 10—5 torr at 100 hours for PS.
• Pump is 20,000 l/s (only 1 runs, other hot stand-by)
• Lose 50% in angle valve
• Lose 50% in baffle (cold trap) for non-condensable
• 1/S net = (1/S pump + 1/S trap + 1/S valve + 1/S tee not in molflo )
• Neglects contribution of cold trap pumping of water vapor,

refrigerant, etc.

• Assumes gas load from leaks is negligible

Hand Calculation Results based on 1 Volume: 1 hour gas load 10 hour gas load Total Gas Load, Q (torr-liters/sec): 0.132 0.0159 net pump speed, l/s 4825.9 4825.9 Vacuum pressure, torr 2.74E-05 3.3E-06

Hand Calculation for DS+TSd:

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• Requirement document; P = 1 x 10—4 torr at 100 hours for DS.
• Pumps are 8,000 l/s each
• (Using 2 pumps, space for 4 available)
• Lose 50% in angle valve
• Lose 50% in baffle (cold trap) for non-condensable
• 1/S net = (1/S pump + 1/S trap + 1/S valve)
• Neglects contribution of cold trap pumping of water vapor,

refrigerant, etc.

• Assumes gas load from leaks and feed throughs is negligible

Hand Calculation Results based on 1 Volume: With Requirements Gas Load at many hours With Gas Load As currently Understood @ 10 hours 2 pumps 2 pumps Total Gas Load, Q (torr-liters/sec): 0.32000 0.24099 net pump speed, l/s 5332 5332 Vacuum pressure, torr 6.00E-05 4.52E-05

MOLFLO+ Methodology:

• A simplified model is created in NX of the PS+TSu or the

TSd+DS

– Circular cross sections modeled as 20 sided polygons to reduce the # of facets. – Solid material in NX = Vacuum, Voids in NX model represent solid material in MOLFLO+ – Write out .stl file as a text file, edit in notepad and save as a .stl – Read into MOLFLO+ (select units, clean up facets, etc.) – Measure area of the facets. – Apply uniform outgassing rate (in mbar-l/sec-cm2) to all the facets

Feb 9, 2017 Dave Pushka | Muon Beamline Vacuum Overview 19

MOLFLO+ Run for baseline configuration: PS+TSd 1 pump with Baffle and valve

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MOLFLO+ Run for baseline configuration: Upstream Muon Beamline Vacuum Volume

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3 x 10-8 torr-l/sec-cm2 average gas load (10 hour gas load), 4731 l/s net pump speed:

This run made with 4731 l/s. A more precise estimate of net pump speed is 4826 l/s). 3x 10-8 torr-l/sec-cm2

• utgassing rate = the

PS gas load @ 10 hours / MOLFLO+ model area. Ptarget = 4.7 x 10-6 torr

MOLFLO+ run for one alternate PS +TSu configuration using 2 pumps:

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Alternate with two pumps with cold traps (9652 l/s): This run made with 10,000 l/s Not much gain compared to 1 pump due to conductance limit in the pipe.

MOLFLO+ run for baseline configuration: Downstream Muon Beamline Vacuum Volume

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MOLFLO+ run for Downstream (TSd+DS) design configuration:

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Gas load = 2 x 10-7 mbar-l/cm2-s. Same methodology as used on the PS Two pumps with cold traps (each @ Speed = 2666 l/s):

Pressure along a facet along the length of the detector solenoid. 0 is at the TSd 100 is at the IFB Clearly shows pressure gradient along bore due to tracker and calorimeter. P at TSU = 7.84 x 10-5 mbar P at TSU = 5.88 x 10-5 torr P min = 4.75 x 10-5 torr

Summary of Meeting Requirement for Pressure Levels:

• Recall, vacuum requirements are:

– Required vacuum level:

• PS + TSu (Upstream);

≤1 x 10-5 torr.

• TSd+DS (Downstream); ≤1 x 10-4 torr.

– Required vacuum pump down time:

• ~100 hours.
• Calculated Vacuum Performance for each are is:

– Upstream (PS+TSu) P = 3.3 x 10-6 torr by hand calculations – Upstream (PS+TSu) P = 4.7 x 10-6 torr by simulation – Downstream (TSd+DS) P = 6 x 10-5 torr by hand calculations – Downstream (TSd+DS) P = 4.7 x 10-5 torr by simulation

• This meets the pressure level requirements.

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Interfaces:

• Section 2 of Mu2e Document 1168 list on six pages every

interface between the Muon beamline vacuum and every

• ther portion of the project. See:

https://mu2e-docdb.fnal.gov:440/cgi-bin/RetrieveFile?docid=1168&filename=Muon_Beamline_Interface_v3.pdf&version=3

– Key Upstream (PS+TSu) interfaces:

• Heat and Radiation Shield (HRS) (End cap welds to the HRS)
• Remote Handling (applies to flanges on the PS End Cap)

– Key Downstream (TSd+DS) interfaces:

• VPSP welds to the Detector Solenoid Inner Bore
• VPSP needs internal rails that match the DS rails

– Anti-proton stopping window (separates Upstream from Downstream muon vacuum volumes). – Everything Else:

See next slide…….

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Interfaces:

– Everything Else:

• Controls (described later in this talk)
• Building (electric power, chilled water, dry instrument air)
• Building & Shielding (Space for equipment, routing of vacuum

exhaust lines, routing of by-pass line)

• Solenoid cryo (need LN2 for the cold traps, GN2 for backfill)
• Accelerator (primary beam entrance and exit pipes)
• Detectors

– Gas loads (leakage, cabling, structure, etc.) – Feedthroughs (Instrumentation Feedthrough Bulkhead) – Detector utilities (cooling, calibration system, signal and power cabling) – Tracker Straw Differential Pressure

– Rely very heavily on the Top Level Assembly (F10002515) for coordinating physical interfaces.

Feb 9, 2017 Dave Pushka | Muon Beamline Vacuum Overview 27

Layout of the Remote Handling Room:

Feb 9, 2017 Dave Pushka | Muon Beamline Vacuum Overview 28

Upstream vacuum pumps located in remote handling room. Vacuum pump exhaust will go thru coalescing filters, then to the air handling duct, then up the M4 beamline

• r outside depending
• n radiation safety

input.

By-Pass line connection PS+TSu and TSd+DS:

Feb 9, 2017 Dave Pushka | Muon Beamline Vacuum Overview 29

Downstream Vacuum pump exhaust to be routed outside of the building.

• Line routing not yet put into F10002515
• Exhaust will be filtered prior to routing

upstairs and out of the building.

By-Pass line connection PS+TSu and TSd+DS:

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By-Pass line connection PS+TSu and TSd+DS Layout work in progress (these dimensions not used in calcs yet):

Feb 9, 2017 Dave Pushka | Muon Beamline Vacuum Overview 31

Vacuum Seal Criteria:

• Seals in the Upstream vacuum system inside of the PS

endcap will be all metal, radiation hard seals where all welded construction is not practical.

• Seals in the Upstream vacuum system inside of the remote

handling room will be either all metal or a combination of elastomeric seal and all metal - requires radiation dose input which has not yet been finalized.

• Seals in the Downstream vacuum system will be elastomeric.
• Seals in the by-pass line (described in the following section)

will be minimized by using all welded construction. Seals at the roughing pump ends will be elastomeric.

Feb 9, 2017 Dave Pushka | Muon Beamline Vacuum Overview 32

Initial Evacuation Criteria:

• Requirements provide a time constraint on the evacuation to
• perating pressure.
• Working plan for Mu2e is to perform it in less than 1 shift

– KTeV took about 1 hour. – NuMI took about 3 days.

• Significant requirement is to keep the differential pressure

across the pbar stopping window (located between the TSu and the TSd) to a fraction of what it can take

– Pbar stopping window thickness determined by the physics requirement, not vacuum requirement – Working design tolerates >50 torr differential – More on this pbar window in the section on windows.

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Simultaneous Pump-Down

• f the Upstream and Downstream ends:

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0.10 1.00 10.00 100.00 1000.00 100 200 300 400 500 600 700 A b s

• l

u t e P r e s s u r e , t

• r

r Elasped Time, minutes

Mu2E Pump Down each vessel (TSd+DS and PS+TSu) using a single pump at the DS end and the by-pass to the PS end

DS+TSd Pressure, torr PS+Tsu Pressure, torr

PS roughing pump can be started in this range, which changes shape of red (PS) curve at times > 400 minutes

Simultaneous Pump-Down

• f the Upstream and Downstream ends:

Feb 9, 2017 Dave Pushka | Muon Beamline Vacuum Overview 35

PS roughing pump started here, which changes shape of red (PS) curve at times > 500 minutes

Desirable point to start diffusion pumps to minimize back steaming

• f oil (described next)

150 microns.

0.01 0.10 1.00 10.00 100.00 1000.00 100 200 300 400 500 600 700 A b s

• l

u t e P r e s s u r e , t

• r

r Elasped Time, minutes

Mu2E Pump Down each vessel (TSd+DS and PS+TSu) using when the Upstream roughing pump started at 500 minutes.

DS+TSd Pressure, torr PS+Tsu Pressure, torr

DS roughing vacuum limited by the roughing line speed. – Future work to investigate and model larger sizing to get better vacuum.

Which diffusion pump oil to use?

• Inputs (in order of importance):

1. Oil adverse affects on the detector

• Must minimize adverse affects of pump oil on detectors

2. Desired operating pressure

• No better than 10-6 torr is required.

3. Oil Back streaming rate

• Must minimize oil backstreaming

4. Service Life

• Radiation Resistance
• Tolerance to Oxidation

– Proper control, fail closed valves, etc. can reduce oxidation potential.

5. Cost

Feb 9, 2017 Dave Pushka | Muon Beamline Vacuum Overview 36

Which diffusion pump oil to use?

DC-702 (Mixture of phenylmethyl and dimethyl cyclosiloxane)

– Resistant to oxidation/hydrolysis – Suitable for 10-5 range – While lower cost, may not be readily available

DC-704 (tetraphenyl tetramethyl trisiloxane)

– Best oxidation resistance – Suitable for 10-7 range – $500 per gallon

DC-705 (pentaphenyl trimethyl trisiloxane)

– Best ultimate pressure – Low back-streaming – $900 per gallon

Octoil

– $300 per gallon

Santovac (Polyphenyl Ether)

– Best ultimate pressure – Very low back streaming at High vacuum – Does not polymerize under ionizing radiation – > $2000 per gallon

Feb 9, 2017 Dave Pushka | Muon Beamline Vacuum Overview 37

Likely our best choices. DC-704 equivalent preferred.

When to Start the Diffusion pumps?

• Crossover is normally between 5 x 10-2 torr and 1.5 x 10-1 torr (50 – 150 microns).

– Below this range mechanical pumps are rapidly loosing efficiency and above this range the back streaming of oil from the diffusion pump increases. – From about 1 x 10-4 torr to the lowest achievable vacuum level of the system, the back streaming rate of a diffusion pump is independent of the inlet pressure. – Keep the period of inlet pressure exceeding 10-2 torr (10 microns) short, (on the order of a few tens of seconds). Extended operation at these pressures will result in unacceptably high amounts of oil back streaming into the vacuum system. – Traps minimize oil back streaming from the diffusion pump at high inlet pressure. For KTeV, the high vacuum valve was opened when the chamber was pumped to less than 10-1 torr (50 to 100 microns – blowers have an ultimate of about 30 microns). – Diffusion pumps were on, hot, foreline connected to the roughing pump, but isolation valve closed. – For KTeV, the vessel pressure rapidly fell – and in about 1 minute, the chamber pressure was in the 10-5 torr range.

• Therefore, start the Mu2e diffusion pumps in a very similar manner – with vessels as close

to 5 x 10-2 (50 microns) as possible. But distance to the roughing pump and gas load may make 50 microns hard to do. Roughing line dimensions will be maximized.

Feb 9, 2017 Dave Pushka | Muon Beamline Vacuum Overview 38

Estimate of the Oil Back streaming in the Upstream (PS+TSu) and Downstream (TSd+DS):

Feb 9, 2017 Dave Pushka | Muon Beamline Vacuum Overview 39 3.657 0.366 0.037 3.240 0.324 0.032 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 bare pump cold baffle Astrotorus Baffle

Liters of Diffusion Pump Oil Lost to Vessel Interior

Oil Contamination for 3 years Operation @ 75% uptime

PS + Tsu: Qty = 1 DIP 12000 DS + TSd: Qty = 2 DIP 8000

This is our Design

Based on published data from Leybold using LEYBONOL LVO 500 (a plain mineral oil) diffusion pump oil. Silicon oil (DC-704 or 705 equivalent) should have lower back streaming rates.

Back Streamed Diffusion Pump Oil Where Does it Go?

• Prediction based on manufacturer’s data for back streaming
• f plain mineral oil is less than a shot glass of oil for 3 years
• peration.
• The silicone oils are reported to have lower back streaming

rates, but I’ve not found a quantified value.

• From KTeV, using un-trapped diffusion pumps, there was

evidence of oil on the bottom of the vessels where the pumps were located.

– Oil film on the vessel bottom made walking difficult. – Oil evidence diminished dramatically as distance from the pumps increased.

• Conclusion is that the oil sticks to the first surface it hits, then

runs down the vessel walls and collects at a low point.

Feb 9, 2017 Dave Pushka | Muon Beamline Vacuum Overview 40

Back Streamed Diffusion Pump Oil Where Does it Go for Mu2e?

• Upstream (PS+TSu):

– Diffusion pump oil will most likely hit the high vacuum pump out line, or angle valve. Calculate 99.76% of the oil will hit the high vacuum pump out line.

• Should consider slightly sloping high vacuum line to drain back to

the diffusion pump inlet so that the oil returns to the pump.

– 0.329% (0.12 ml for three years operation based on mineral oil pump fluid) will hit the PS End Cap.

• Expectation is that the oil will stick to the PS end cap and collect at

the bottom (just like in KTeV).

• Should consider including a small drain in PS end cap

– No line of slight to the target exists.

• Do not expect the target to ‘see’ any measurable diffusion pump
• il.

Feb 9, 2017 Dave Pushka | Muon Beamline Vacuum Overview 41

Back Streamed Diffusion Pump Oil Where Does it Go for Mu2e?

• Downstream (TSd+DS):

– Diffusion pump oil will most likely hit the angle valve and VPSP

• nozzle. Calculate 84% of the oil will hit the angle valve or

nozzle.

• Should consider slightly sloping VPSP nozzles to drain back to the

diffusion pump inlet so that the oil returns to the pump.

– 16% (5.18 ml for three years operation based on mineral oil pump fluid) will make it into the DS vacuum space.

• Expectation is that the oil will hit the Muon Beam Stop (MBS).

– No line of slight to anything upstream of the MBS.

• Do not expect the calorimeter or tracker or anything upstream of

the MBS to ‘see’ any measurable diffusion pump oil.

Feb 9, 2017 Dave Pushka | Muon Beamline Vacuum Overview 42

Back Streamed Diffusion Pump Oil, But what if some oil got on Detector Items?

• Silicone Diffusion pump oils are:

– Electrically non-conductive.

• A coating on an electronics board will not cause a short circuit.
• Transformers operate immersed in a similar oil polydimethyl

siloxane.

– Non-Reactive

• Specifically engineered to be non-reactive

– Do not self polymermize – Reaction with straw tube material can be tested to verify these fluids are not damaging – DC-704 is tetraphenyl tetramethyl trisiloxane C28H32O2Si3 MW = 484.81 – Dc705 is pentaphenyl trimethyl trisiloxane C33H34O2Si3 MW = 546.88

Feb 9, 2017 Dave Pushka | Muon Beamline Vacuum Overview 43

Diffusion Pump Oil Quality Monitoring

• Diffusion Pump Oil is subject to ‘cracking’ when exposed to
• xygen when hot.

– Silicon diffusion pump oils are the most cracking resistant. – DC-704 diffusion pump oil from KTeV never showed evidence of

• cracking. Color remained water clear.

– If a serious mis-operation occurs, oil will need to be changed.

• A non-trivial effort
• Upstream end requires radiation analysis
• Downstream end requires opening the CRV and External shielding

– Fail closed valves and PLC logic to prevent inadvertent

• perational errors worked well on KTeV to maintain diffusion

pump oil quality. – Expect to do the same for Mu2e.

Feb 9, 2017 Dave Pushka | Muon Beamline Vacuum Overview 44

Keeping the muon beamline (relatively) clean?

• Assume solenoid inner bores are not cleaned for vacuum service upon receipt

from GA or TD, but meet the FNAL cleanliness specifications

• Assume HRS is not cleaned for vacuum service upon receipt – cleaned upon

receipt.

• Assume PS End Cap, VPSP, IFB are not cleaned for vacuum service upon receipt

from vendor / fabricator – these to be cleaned by FNAL upon receipt

• Request Collimators (part of muon beamline) are assembled under clean

conditions with minimal contamination from finger prints, and all parts are washed with soap and water, distilled water rinse, then Isopropyl alcohol (IPA) wipe and bagged prior to installation in the TS bore.

• Clean (clean means: washed with soap and water, distilled water rinse, then

Isopropyl alcohol (IPA) wipe and bagged with an HDPE plastic sheeting which is sealed closed. Apply to:

– HRS after welding is completed to seal between HRS bore and PS – PS end cap prior to welding and after welding to HRS is complete – VPSP after welding is completed to join the DS and VPSP – TS warm bores after installation

Feb 9, 2017 Dave Pushka | Muon Beamline Vacuum Overview 45

Keeping the muon beamline (relatively) clean?

• Once Cleaned, Maintain Cleanliness by:

– Covering All Open Ports with a metal blind flange or at least plastic sheeting. – Purge with clean, dry air if possible.

• Biggest source of gas load is in the Downstream (TSd+DS)

because of the detectors and non-solid, non-metal components including significant cabling.

• Will need to work with the detector people to:

– Keep cabling clean, free from skin oils and general dirt. – Keep detector train covered when outside of DS – Minimize contamination since contamination = gas load – Etc.

Feb 9, 2017 Dave Pushka | Muon Beamline Vacuum Overview 46

Summary of Meeting Requirement for Cleanliness:

• Recall, Cleanliness requirements are:

– Required pre-operational cleanliness:

• standard high vacuum cleaning and degreasing.

– Required operational cleanliness:

• minimize, but not eliminate vacuum pump oil back-streaming.
• We can meet the requirements for the Cleanliness Levels as

long as we are careful, perform the work, and allow sufficient time for doing a complete cleaning.

• We also need significant help from the solenoid, detector,

magnetic field measuring and electronics people to help achieve a clean system.

Feb 9, 2017 Dave Pushka | Muon Beamline Vacuum Overview 47

Initial Pump down and Leak Testing (QA/QC):

Feb 9, 2017 Dave Pushka | Muon Beamline Vacuum Overview 48

• Plan is to initially pump down the warm vacuum spaces prior to

detector train installation.

• Will perform helium mass spectrometry leak testing during the

initial evacuation to locate and repair vacuum leaks.

• May require several iterations to identify, find, and repair

leaks to air.

• Goal is to make the air leaks small with respect to the
• utgassing and tracker gas loads.
• Then, second iteration to evacuate the Downstream (and the

Upstream) with the Detector Train installed in the DS.

Deliverable Vessels for the Muon Beam Line:

• PS End Cap and Vacuum Pump-out Line:

Feb 9, 2017 Dave Pushka | Muon Beamline Vacuum Overview 49

Deliverable Vessels for the Muon Beam Line:

Feb 9, 2017 Dave Pushka | Muon Beamline Vacuum Overview 50

• VPSP and IFB:
• VPSP modeled in Native NX (in TC)
• IFB not yet modeled in Native NX (this image is from a STEP

file):

Structural Analysis of the Vessels and FESHM 5033 Conformance:

Feb 9, 2017 Dave Pushka | Muon Beamline Vacuum Overview 51

• PS end Cap, and the Vacuum Pump Spool Piece (VPSP) were

analyzed by Vic Guarino at ANL and shown to meet ASME Code requirements – His Write-Up is in Mu2e Docdb 4832.

• PS end Cap and the 3 meter Vacuum Line and Pump Tee were

analyzed by Ingrid Fang (PPD/MD/EAG) using ANSYS and found to meet ASME Code requirements – Her Write-Up is in Mu2e Docdb 4832.

• I’ve performed initial NASTRAN analysis of the Instrumentation

Feed Thru Bulkhead (IFB) and found that it meet ASME Code

• requirements. However, the formal analysis has not yet been

completed as the feedthrough plates remain loosely defined.

• Calculations on the cover plates used for shop leak testing have

not been started.

Safety Relief Valves:

Feb 9, 2017 Dave Pushka | Muon Beamline Vacuum Overview 52

• All portions of the Upstream and Downstream vacuum volumes

(including the solenoid cryostats) are designed for:

• Full vacuum
• 5 psig internal pressure.
• Relief valves for the vacuum space will be installed on both

ends so that accident conditions do not cause internal pressure to exceed 5 psig.

• Relief valves have not yet been sized because the size of the
• ver pressure sources (tracker gas, detector coolant(s),

calorimeter calibration system, etc.) are not fully known yet. Relief sizing depends on the source capacity.

Summary of Vessels and FESHM 5033 Conformance:

• Vessel Requirements Originate from FESHM 5033
• We have demonstrated vessel designs that meet FESHM

5033 for the PS End Cap and VPSP.

• IFB analysis and relief valve sizing are still a work in progress

and depend on inputs from other portions of the project to allow completion.

Feb 9, 2017 Dave Pushka | Muon Beamline Vacuum Overview 53

Thin Windows:

• FESHM 5033.1 applies and draws on the TM-1380 methods

for thin windows; both rigid (metal) and non-rigid (kapton).

– Uses a iterative solution to determine the deflection – With the exception of the primary beam exit window, beam heating is not encountered. – Analysis of the beam heating of the primary beam exit window has not yet been evaluated.

Feb 9, 2017 Dave Pushka | Muon Beamline Vacuum Overview 54

Thin Windows – Beam Exit Window on PS End Cap:

Feb 9, 2017 Dave Pushka | Muon Beamline Vacuum Overview 55

Per FESHM 5033.1& TM-1380: titanium For Rigid Materials, t> 0.003 inches Diameter, mm 406.4 Diameter, inches 16 Uniform Pressure, q (psi) 14.7 Radius of Window, a (inches) 8 Material Ti6%Al4%V Young's Modulus, E (psi)

16,400,000

Chosen Window Thickness, t (inches) 0.012 Chosen Window Thickness, t (mm) 0.3048 Poisson's Ratio, v 0.3 K1 = 5.33/(1-v^2) 5.86 K2 = 2.6 / (1-v^2) 2.86 K3 = 2/(1-v) 2.86 K4 = 0.976 0.976 Yield Stress, Fy (psi) 120,000 Ultimate Stress, Fu (psi) 130,000 Allowable Stress, S (psi) based on Material 65,000 Stress from E*(t/a)^2 * [K3*(y/t) + K4*(y/t)^2] 60,519 Check if Stress from Geometry > Material Allowable Stress thcknss ok Deflection, y (inches) {trial value} 0.4747 qa^4/Et^4 177055.10 K1*(y/t) + K2*(y/t)^3 177055.10 difference 0.000 DEFLECTION, in 0.4747 t/2 0.0060 Thin Criteria Met (y > t/2)

yes

Thin Windows – Target Access Window on PS End Cap:

Feb 9, 2017 Dave Pushka | Muon Beamline Vacuum Overview 56

Per FESHM 5033.1& TM-1380: titanium For Rigid Materials, t> 0.003 inches Diameter, mm 558.8 Diameter, inches 22 Uniform Pressure, q (psi) 14.7 Radius of Window, a (inches) 11 Material Ti6%Al4%V Young's Modulus, E (psi)

16,400,000

Chosen Window Thickness, t (inches) 0.018 Chosen Window Thickness, t (mm) 0.4572 Poisson's Ratio, v 0.3 K1 = 5.33/(1-v^2) 5.86 K2 = 2.6 / (1-v^2) 2.86 K3 = 2/(1-v) 2.86 K4 = 0.976 0.976 Yield Stress, Fy (psi) 120,000 Ultimate Stress, Fu (psi) 130,000 Allowable Stress, S (psi) based on Material 65,000 Stress from E*(t/a)^2 * [K3*(y/t) + K4*(y/t)^2] 57,579 Check if Stress from Geometry > Material Allowable Stress thcknss ok Deflection, y (inches) {trial value} 0.6339 qa^4/Et^4 125012.72 K1*(y/t) + K2*(y/t)^3 125012.72 difference 0.000 DEFLECTION, in 0.6339 t/2 0.0090 Thin Criteria Met (y > t/2)

yes

Thin Windows – Extinction Window on PS End Cap:

Feb 9, 2017 Dave Pushka | Muon Beamline Vacuum Overview 57

Mu2e Extinction Window:

Per FESHM 5033.1& TM-1380: titanium For Rigid Materials, t> 0.003 inches Diameter, mm 152.4 Diameter, inches 6 Uniform Pressure, q (psi) 14.7 Radius of Window, a (inches) 3 Material Ti6%Al4%V Young's Modulus, E (psi)

16,400,000

Chosen Window Thickness, t (inches) 0.005 Chosen Window Thickness, t (mm) 0.127 Poisson's Ratio, v 0.3 K1 = 5.33/(1-v^2) 5.86 K2 = 2.6 / (1-v^2) 2.86 K3 = 2/(1-v) 2.86 K4 = 0.976 0.976 Yield Stress, Fy (psi) 120,000 Ultimate Stress, Fu (psi) 130,000 Allowable Stress, S (psi) based on Material 65,000 Stress from E*(t/a)^2 * [K3*(y/t) + K4*(y/t)^2] 56,984 Check if Stress from Geometry > Material Allowable Stress thcknss ok Deflection, y (inches) {trial value} 0.1718 qa^4/Et^4 116165.85 K1*(y/t) + K2*(y/t)^3 116165.85 difference

• 0.001

DEFLECTION, in 0.1718 t/2 0.0025 Thin Criteria Met (y > t/2)

yes

Thin Windows – Pbar Window at TSu/TSu interface (0,0,0) :

Feb 9, 2017 Dave Pushka | Muon Beamline Vacuum Overview 58

This calculation shows how the 50 torr maximum differential pressure was determined.

Anti Proton Stopping Window at COL 3

Minimum thickness and diameter from Mu2e Docdb 3179

Per FESHM 5033.1& TM-1380: S200FH Beryllium S200FH Beryllium For Rigid Materials, t> 0.003 inches Diameter, mm

450 450

Diameter, inches

17.72 17.72 Uniform Pressure, q (psi) 0.97 14.70

Radius of Window, a (mm)

225 225

Radius of Window, a (inches)

8.858 8.858 Material

S200FH Beryllium S200FH Beryllium

Young's Modulus, E (psi)

44,000,000 44,000,000

Chosen Window Thickness, t (inches) 0.005 0.005 Chosen Window Thickness, t (mm) 0.127 0.127

Poisson's Ratio, v 0.032 0.032 K1 = 5.33/(1-v^2) 5.34 5.34 K2 = 2.6 / (1-v^2) 2.60 2.60 K3 = 2/(1-v) 2.07 2.07 K4 = 0.976 0.976 0.976 Yield Stress, Fy (psi) 44,000 44,000 Ultimate Stress, Fu (psi) 60,000 60,000 Allowable Stress, S (psi) based on Material 30,000 30,000 Stress from E*(t/a)^2 * [K3*(y/t) + K4*(y/t)^2] 27,320 163,113

Check if Stress from Geometry > Material Allowable Stress

thickness ok too thin, n.g.

Deflection, y (inches) {trial value} 0.2182 0.5407

qa^4/Et^4 216539.07 3291393.80 K1*(y/t) + K2*(y/t)^3 216539 3291394 difference

0.000 0.000 DEFLECTION, in 0.2182 0.5407

t/2 0.0025 0.0025 Thin Criteria Met (y > t/2) yes yes

Thin Windows – Pbar Window at 0,0,0 with Kapton:

Feb 9, 2017 Dave Pushka | Muon Beamline Vacuum Overview 59

Anti Proton Stopping Window at COL 3

Per FESHM 5033.1& TM-1380: For Flexible (non-Rigid) Materials, t< 0.003 inches Material Kapton polyamide Kapton polyamide t = thickness of window, in

0.0047 0.0047

t = thickness of window, mm

0.12 0.12

a = radius of window measured at O-ring groove on flange, mm 225 225 a = radius of window measured at O-ring groove on flange, inches

8.858 8.858

q = uniform pressure on window (psi)

0.97 14.69

q = uniform pressure on window (torr)

50 50

S = Allowable Stress (psi)

9000 9000

E = Young's Modulus of window material (psi)

310000 310000

y = window deflection, inches Eqn 4.1a: S > 0.423*(E*q^2*a^2/t^2)^(1/3)

8797 13452 N.G.

Eqn 4.1b: y = 0.662*a*(q*a/(E*t))^(1/3)

0.2467 0.6112

Thin Windows – IFB Window with Low Strength Titanium:

Feb 9, 2017 Dave Pushka | Muon Beamline Vacuum Overview 60

STM Window on the IFB

Per FESHM 5033.1& TM-1380: Titanium Grade 2 For Rigid Materials, t> 0.003 inches Diameter, mm

200

Diameter, inches

7.87 Uniform Pressure, q (psi) 14.7 Radius of Window, a (inches) 3.937 Material

Grade 2

Young's Modulus, E (psi)

15,500,000 Chosen Window Thickness, t (inches) 0.050 Chosen Window Thickness, t (mm) 1.27

Poisson's Ratio, v 0.3 K1 = 5.33/(1-v^2) 5.86 K2 = 2.6 / (1-v^2) 2.86 K3 = 2/(1-v) 2.86 K4 = 0.976 0.976 Yield Stress, Fy (psi) 40,000 Ultimate Stress, Fu (psi) 50,000 Allowable Stress, S (psi) based on Material 25,000 Stress from E*(t/a)^2 * [K3*(y/t) + K4*(y/t)^2] 24,829

Check if Stress from Geometry > Material Allowable Stress

thickness ok

Deflection, y (inches) {trial value} 0.1023

qa^4/Et^4 36.46 K1*(y/t) + K2*(y/t)^3 36.46 difference 0.000

DEFLECTION, in 0.1023

t/2 0.0250 Thin Criteria Met (y > t/2)

yes

Thin Windows – IFB Window with Kapton or Mylar:

Feb 9, 2017 Dave Pushka | Muon Beamline Vacuum Overview 61

STM Window on the IFB

Per FESHM 5033.1& TM-1380: For Flexible (non-Rigid) Materials, or t< 0.003 inches

20 cm dia

Material mylar (PET) Kapton polyamide t = thickness of window, in

0.010 0.020

t = thickness of window, mm

0.25 0.51

a = radius of window measured at O-ring groove on flange, inches

3.94 3.94

a = radius of window measured at O-ring groove on flange, mm

100.00 100.00

q = uniform pressure on window (psi)

14.69 14.69

S = Allowable Stress (psi)

13500.00 9000.00

E = Young's Modulus of window material (psi)

710000.00 310000.00

y = window deflection, inches Eqn 4.1a: S > 0.423*(E*q^2*a^2/t^2)^(1/3)

12158.65 5810.76

Eqn 4.1b: y = 0.662*a*(q*a/(E*t))^(1/3)

0.21 0.22

Stress Criteria Met:

Yes Yes

Summary of Thin Windows:

• Thin Window Requirements Originate from FESHM 5033.1
• Physics Requirements are subject to refinement as

simulations are performed.

• We have thin window solutions that meet FESHM and meet

the baseline physics requirements.

Feb 9, 2017 Dave Pushka | Muon Beamline Vacuum Overview 62

Interlocks and Controls:

• Integrated with the Mu2e Process Controls

– Review of controls held in January 2016 – Ian Young is the contact – Includes solenoid controls and Muon beam line vacuum – Will have output to ACNET so ACNET can provide monitoring (not control) of the vacuum equipment.

• Will provide an interlock to the Mu2e detector systems for

interlocking the High Voltage detector electronics in the vacuum during the pump down to prevent corona discharge

• Will provide analog data to the tracker so that the differential

pressure across the tracker straws can be maintained within the acceptable range.

Feb 9, 2017 Dave Pushka | Muon Beamline Vacuum Overview 63

Interlocks:

• Plan is to use manually controlled equipment

– No automated pump down – Ability to connect to ACNET for remote operation or manual

• peration.
• Air operated vacuum valves with solenoids that cause

vacuum valves to close on loss of power. Air receiver (outside muon beam line scope) will have sufficient reservoir capacity to close all valve on power loss.

• Loss of AC power will cause all vacuum valves to close. (Air

required to close valve)

– Prevents contamination of vessels by pump oil on loss of AC power.

Feb 9, 2017 Dave Pushka | Muon Beamline Vacuum Overview 64

Interlocks verses a Safety System:

• Interlocks are NOT part of a safety system.

– Interlocks are NOT required to protect people. – Interlocks do protect equipment.

• Identical to a loss of oil pressure causing a compressor to shut

down, the interlocks will minimize the damage to equipment in the event of a component failure.

• Interlocks will provide a third level, back-up method to ensure

differential pressure across the anti-proton stopping window is not exceeded during initial evacuation.

– Primary method is the open by-pass line – Secondary method is the manned operation.

• Similar process for repressurization so that differential across the

tracker straws remains within the permissible range.

Feb 9, 2017 Dave Pushka | Muon Beamline Vacuum Overview 65

Pressure Gauge Location List:

• Convectron type vacuum gauging (1 atmosphere to 1x10-4

torr range) located:

– Upstream (PS+TSu):

• All located in the Remote Handling Room
• Between diffusion pump inlet and the Isolation Valve outlet
• On diffusion pump foreline
• On the roughing pump inlet
• On the backing pump inlet
• On the bypass line

– Downstream (TSd+DS):

• Between diffusion pump inlet and the Isolation Valve outlet
• On diffusion pump foreline
• On the roughing pump inlet
• On the bypass line
• Inside the vacuum space, near the Tracker and Calorimeter.

Feb 9, 2017 Dave Pushka | Muon Beamline Vacuum Overview 66

Pressure Gauge Location List:

• Ion type vacuum gauging (< 1x10-4 torr range) located:

– Upstream (PS+TSu):

• in the Remote Handling Room
• Between diffusion pump inlet and the Isolation Valve outlet (likely on the

angle valve body)

– Downstream (TSd+DS):

• On one of the instrumentation ports on the VPSP. Can include an

internally mounted on near the tracker.

• Residual Gas Analyzer (with capillary and differential pump):

– Connection on the Upstream (PS+TSu):

• in the Remote Handling Room
• Between diffusion pump inlet and the Isolation Valve outlet (likely on the

angle valve body)

– Connection on the Downstream (TSd+DS):

• On one of the instrumentation ports on the VPSP.

Feb 9, 2017 Dave Pushka | Muon Beamline Vacuum Overview 67

Input / Output (I/O) List and Description:

• Controls for each vacuum pump (both the mechanical pumps

and the diffusion pumps) will have the following I/O:

– Start – Stop – Contactor status (this is an auxiliary contact to indicate that the motor starter relay is pulled in or not) – Current switch (this indicates that the motor or heater is drawing current) – Energize signal for a cooling water solenoid valve (to start the flow of cooling water when the pump is operating) – Cooling water flow switch (to read back that the cooling water is flowing) – Cooling water temperature output (a 4-20 ma signal to read back the cooling water outlet temperature) – Oil temperature output (a 4-20 ma signal to read back the oil temperature) – Oil level output (a 4-20 ma signal to read back the oil level)

Feb 9, 2017 Dave Pushka | Muon Beamline Vacuum Overview 68

Input / Output (I/O) List and Description (continued):

• Each diffusion pump will also have:

– Oil fill valve (this is a very small remotely operated valve used to allow the diffusion pump working fluid (oil) to be added to the pump as needed without manual access to the high radiation and high magnetic field regions). – Cooling Water Flow instrumentation (temperature, flow meter, pressure gauges) as described previously

Feb 9, 2017 Dave Pushka | Muon Beamline Vacuum Overview 69

Input / Output (I/O) List and Description (continued):

• Each cold trap for the diffusion pump will have:

– Energize signal for a LN2 solenoid valve (to start the flow of LN2 when the pump is operating) – GN2 flow switch (to read back that the LN2 is flowing in by measuring the GN2 output from the cold trap) – LN2 level probe on the phase separator on the cold trap to show the cold trap is flooded with LN2. – Cold trap temperature output (a 4-20 ma signal to read back the cold trap temperature) used to confirm the cold trap is cold and therefore working.

Feb 9, 2017 Dave Pushka | Muon Beamline Vacuum Overview 70

Failure Modes Effect Analysis (FMEA) – Key Items:

Event Result Conclusion Satisfactory Condition

Loss of AC Power Solenoid valves cause pneumatic vacuum valves to close. Diffusion pump heater(s) de-energize. Mechanical Pumps stop. Vacuum System goes to static mode. Absolute pressure rises due to

• utgassing. By pass opened to

protect pbar window if P > 10 torr. Yes Loss of a diffusion pump heater (open circuit) Control system cause Solenoid valves to cause pneumatic vacuum valves to

• close. Diffusion pump heater(s)
• deenergize. Mechanical Pumps

continue. Vacuum System goes to intermediate

• mode. Absolute pressure rises due to
• utgassing.

Yes Loss of a mechanical pump Control system cause Solenoid valves to cause pneumatic vacuum valves to

• close. Diffusion pump heater(s) are
• deenergized. Mechanical Pumps

continue. Vacuum System goes to static mode. Absolute pressure rises due to

• utgassing.

Yes Small Leaks develop in a vacuum window Pressure rises. Alarms are indicated. Operator intervention may drop beam permit. Vacuum system continues to operate Yes Large Leaks develop in a vacuum window Pressure rises. Alarms are indicated. Controls system drops beam permit. Control system cause Solenoid valves to cause pneumatic vacuum valves to

• close. Diffusion pump heater(s)

deenergize. Diffusion pumps isolated with valves, heaters deenergized. Mechanical pumps continue to operate. Yes Large, instantaneous vacuum window failure Pressure rises. Alarms are indicated. Controls system drops beam permit. Control system cause Solenoid valves to cause pneumatic vacuum valves to

• close. Diffusion pump heater(s) de-
• energize. Bypass line opens between

DS and PS. pbar window fails due to high differential pressure. Tracker straws are likely damaged. Detector electronics may have arc over shorts as the pressure rises into the corona

• region. Radioactive items from PS

may contaminate the DS. mitigation required – Follow FESHM 5033.1 for thin windows Feb 9, 2017 Dave Pushka | Muon Beamline Vacuum Overview 71

Repressurization and other things:

• Dry air and dry nitrogen repressurization plan:

– Re-pressurize both the PS+TSu and TSd+DS simultaneously – Use a low pressure regulator (to provide gas at a few inches of water column pressure) to several solenoid valves with differently sized Cv – As vessel pressure approaches atmosphere, open larger solenoid valves to maintain pressure increase rate while the differential pressure approaches a small value.

• When open to atmosphere, admit dry air to both vacuum

spaces near where TSu and TSd meet.

– Use this to reduce the vessel exposure to moisture containing room air. – For Upstream, N2 reduces O2 residue gas = good for target

• Need to size flow to also meet radiation safety requirements

Feb 9, 2017 Dave Pushka | Muon Beamline Vacuum Overview 72

Other Things:

• There is a desire on the part of the accelerator people to

include these provisions in the Upstream vacuum space:

– Removable flange over a port for a borescope access to allow visual inspection of the primary target at perhaps two locations:

• From the primary beam pipe into the production solenoid
• From the large Upstream vacuum pump out line

– Likely should include a small metal sealed flange near the bottom of the PS end cap weldment to allow removal of any liquids or debris that may collect there.

Feb 9, 2017 Dave Pushka | Muon Beamline Vacuum Overview 73

Summary: We have……

• Systems that achieve the required vacuum levels.
• Shown that 2 of the 3 vessels meet FESHM (and will be able

to show the 3rd vessel and relief devices do)

• Thin windows that meet FESHM and physics requirements.
• Selected equipment that will operate satisfactorily in the

magnetic fields.

• Plans for initial vessel cleaning that are consistent with

achieving the requirements.

• Predictions for the diffusion pump oil contamination that meet

the requirements.

• Initial evacuation and repressurization plans that will protect

the pbar stopping window

Feb 9, 2017 Dave Pushka | Muon Beamline Vacuum Overview 74

Thank-you and Acknowledgements:

• Many People contributed to the content presented above. A

big thank-you everyone and especially to:

– Kurt Krempetz – Jim Popp – Cary Kendziora – Ian Young – Alex Chen – Chris Jensen – & George Ginther (who suffered thru many bad drafts).

Feb 9, 2017 Dave Pushka | Muon Beamline Vacuum Overview 75

Back-Up Material (FEM Risk Assessment):

• Fermilab Engineering Manual (FEM) Risk Assessment:

Feb 9, 2017 Dave Pushka | Muon Beamline Vacuum Overview 76

Engineering Risk Assessment

Project:Mu2e Muon Beamline Vacuum System Lead Engineer:Dave Pushka Department:AD/TD Date:June 1, 2014

Engineering Risk Element High Chapter A B C D E F G Risk Subtotal Assessment 1 Requirements and Specifications 1 2 2 ≥10 5 Standard Risk 3 Requirements and Specification Review 1 2 3 2 2 ≥16 10 Standard Risk 4 System Design 1 2 1 2 2 1 ≥19 9 Standard Risk 5 Engineering Design Review 1 2 1 2 2 1 ≥19 9 Standard Risk 6 Procurement and Implementation 2 3 2 2 1 ≥16 10 Standard Risk 7 Testing and Validation 1 2 2 1 ≥13 6 Standard Risk 8 Release to Operations 2 ≥4 2 Standard Risk 9 Final Documentation 2 2 ≥7 4 Standard Risk Project Risk Element High H I J K L M N O Risk Subtotal Assessment 2 4 2 2 3 4 1 4 ≥25 22 Standard Risk Engineering Risk Elements Project Risk Elements A Technology H Schedule B Environmental Impact I Interfaces C Vendor Issues J Experience / Capability D Resource Availability K Regulatory Requirements E Safety L Project Funding F Quality Requirements M Project Reporting Requirements G Manufacturing Complexity N Public Impact O Project Cost

Key Outgassing Rate Values for Metals:

• Stainless Steel:

– Using 2.1 x 10-8 torr-l/cm2-s @ 10 hours (from Elsey)

• Not polished, not ultrasonically cleaned, not baked.
• Schamus lists 2.0 x 10-8 torr-l/cm2-s @ 10 hours
• Aluminum:

– Using 3.2 x 10-8 torr-l/cm2-s @ 10 hours (from Elsey)

• For anodized, not ultrasonically cleaned, not baked.
• Tungsten:

– Using 3 x 10-8 torr-l/cm2-s @ 10 hours (extrapolated from Dayton data at 1 hour)

Feb 9, 2017 Dave Pushka | Muon Beamline Vacuum Overview 77

Key Outgassing Rate Values for non metals:

• Kapton (possible for anti-proton stopping window):

– Using 1 x 10-7 torr-l/cm2-s @ 10 hours (Ferro-Luzzi for 40 hours)

• High Density Polyethylene (HDPE) (used for the absorbers):

– Using 8 x 10-8 torr-l/cm2-s @ 10 hours.

• Polyamide (applicable to bore heaters):

– Using 1 x 10-6 torr-l/cm2-s @ 10 hours

• G-10 (part of the Calorimeter):

– Using 9 x 10-7 torr-l/cm2-s @ 10 hours. – Beams division paper says x ~10-6 torr-l/cm2-s

Feb 9, 2017 Dave Pushka | Muon Beamline Vacuum Overview 78

Key Outgassing Rate Values for non metals (continued):

• B-Stage wrapped copper (Collimators):

– Using 9 x 10-7 torr-l/cm2-s for the collimators based on a paper circa 1969 from NASA for the outgassing of a b-stage insulated magnet coil for time = 10 hours. Based on measurements at 53C.

Feb 9, 2017 Dave Pushka | Muon Beamline Vacuum Overview 79

Back-Up Material (Equipment Catalog Cuts and Performance Curves – Mechanical Pumps):

• Equipment Catalog Cuts:

Feb 9, 2017 Dave Pushka | Muon Beamline Vacuum Overview 80

Back-Up Material (Equipment Catalog Cuts and Performance Curves – Diffusion Pumps):

Feb 9, 2017 Dave Pushka | Muon Beamline Vacuum Overview 81

Back-Up Material (Equipment Performance Curves – Upstream Diffusion Pump and Blower/Mechanical Pump):

Feb 9, 2017 Dave Pushka | Muon Beamline Vacuum Overview 82

Back-Up Material (Equipment Catalog Cuts and Performance Curves – Diffusion Pump Oil):

Feb 9, 2017 Dave Pushka | Muon Beamline Vacuum Overview 83

George’s Keeping the muon beamline (relatively) clean?

• Production Solenoid

– How will GA protect the warm bore during shipping?

• Heat and Radiation Shield

– How will the HRS warm bore be protected?

• Transport Solenoids

– Will the solenoid team be providing blank offs for the flanges at the TSu/TSd interface? – How will the incident proton line be protected? – How will the upstream end of TSu and the downstream end of Tsd be protected? – Should the COL1 housing be designed to support mounting of a cap for the upstream end of the TSu warm bore? – Should the COL5 housing be designed to support mounting of a cap for the downstream end of the TSd warm bore?

• Detector Solenoid

– How will GA protect the warm bore during shipping? – Planning on blank offs for the VPSP ports – How about the IFB?

• How will the PS/TSu interface be “sealed” until the interconnect is installed?
• Will the TSu/TSd seal be used to keep that region sealed until put into service?
• How will the TSd/DS interface be “sealed” until the interconnect is installed?

Feb 9, 2017 Dave Pushka | Muon Beamline Vacuum Overview 84

George’s Keeping the muon beamline (relatively) clean?

Feb 9, 2017 Dave Pushka | Muon Beamline Vacuum Overview 85

Stray fields and equipment

• Jim Kilmer

Basis of data for 15’ BC

• Used the calculated field map for the bubble chamber

solenoid

• Measured locations of equipment in the building with respect

to the solenoid

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15 Foot BC experience

• 24 V DC air solenoids @ 400-600 G
• 5-7HP 3 phase motors @ 600 G
• Turbomolecular pumps @ 10’s of G
• Diffusion pumps @ 4KG
• Ion Pumps @ 600 G
• Ion Gages @ 600G
• Dzero used Turbos and vacuum instruments in 50-100 G field

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Planned Field tests for Mu2e

• Tests of turbomolecular pump, scroll pump, roots pump in a

field

• Use the KTEV magnet – Aperture ~10’ by 7’ by 10’
• Max field 4KG

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