Mu2e Muon Beamline Vacuum Overview - INDICO-FNAL (Indico)...2017/02/09 · TSU Closure Cylinder Y 11,293 30 316L 2.10E-08 2.37E-04 Colimator 1, col 1 43,990 4.15E-04 F10043611 Shim,

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:

Feb 9, 2017Dave Pushka | Muon Beamline Vacuum Overview2

• 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:


• 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:


Mu2e 0,0,0& pbar window

UpstreamVacuum

Downstream Vacuum

Upstream vacuum pumps

Downstream Vacuum Pumps

Over View of the Geography:


Hardware Deliverables for Muon Beamline Vacuum:


Vacuum Pump Spool Piece, VPSPInstrumentation Feed Through Bulkhead, IFB

Vacuum By-Pass LineProduction Solenoid End CapAnd 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


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


Pump out Line Bore

PS-TS and TS-TSInterface Area

COL 1 and 3u

Details of the View of the Areas in the Downstream

(TSd+DS) Vacuum Volume:


Detector SolenoidVPSPIFBCol 5TSdCol3

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:


Outgassing and Vacuum Calculation Methodology:


• 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:


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


PS Vacuum:

contributes

to

outgassing Outgassing

Area temperature material

10 hour

outgassing 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

TSU cone Y 18,484 30 316L 2.10E-08 3.88E-04

TSU horz cylinder Y 23,734 30 316L 2.10E-08 4.98E-04

TSU U.S. end ring Y 13,645 30 316L 2.10E-08 2.87E-04

TsU bore, straight sections Y

TsU bore, truncated cones Y

TSU bore all Y 104,042 30 316L 2.10E-08 2.18E-03

TSU Vertical End Face at Col 3a Y 18,568 30 316L 2.10E-08 3.90E-04

TSU O.D. Cylinder Y 9,191 30 316L 2.10E-08 1.93E-04

TSU Closure Ring Y 5,932 30 316L 2.10E-08 1.25E-04

TSU Closure Cylinder Y 11,293 30 316L 2.10E-08 2.37E-04

Colimator 1, col 1 43,990 4.15E-04

F10043611 Shim, Transfer Ball (4 instances) N - 30 316L 2.10E-08 0.00E+00

F00482918 Flange Coll 1 Shell Y 2,467 30 316L 2.10E-08 5.18E-05

F00482919 End Plate Coll 1 Shell Y 970 30 316L 2.10E-08 2.04E-05

F09079605 COL 1 shell ACS Y 15,301 30 316L 2.10E-08 3.21E-04

FC0051514 beryllium (2 instances) Y 45 30 Be

F10041085 Outer Wedge, C bored N - 30 Cu

F00482920 Outer wedge COLL 1 (30 instances) N - 30 Cu

F00482921 Inner wedge COLL 1 (24 instances) N - 30 Cu

F10041031 Graphite Insert, COLL 1 (24 instances) N - Graphite

FC0052520 alt 1 carbon (24 instances) Y 24,191 30 Carbon

FC0045055 alt 48 Fglass Tape(24 instances) N - Fglass 2.30E-07 0.00E+00

FC0045055 alt 47 Fglass Tape(30 instances) N - Fglass 2.30E-07 0.00E+00

F10041083 End Segment, COLL 1 Y 787 30 316L 2.10E-08 1.65E-05

FC0051240 Ball transfer (4 instances) Y 228 30 316L 2.10E-08 4.78E-06

Colimator 3a, Col 3a 88,704

F00482948, Ring gear COL 3 Y 20,145 30 316L 2.10E-08 4.23E-04

F00482925, flange col 3 outer shell Y 2,528 30 316L 2.10E-08 5.31E-05

F00482924, COL 3 Outer Shell Y 22,778 30 316L 2.10E-08 4.78E-04

F00482951, bearing ring Y 1,918 30 316L 2.10E-08 4.03E-05

F00482951, bearing ring Y 1,918 30 316L 2.10E-08 4.03E-05

F10040810, gear stop Y 30 30 316L 2.10E-08 6.29E-07

FC0051240, ball transfer (2 instances) Y 114 30 316L 2.10E-08 2.39E-06

F10043611, Shim, Transfer Ball N - 30 316L 2.10E-08 0.00E+00

F10043611, Shim, Transfer Ball N - 30 316L 2.10E-08 0.00E+00

F10040007, Bearing Retaining Ring Y 1,706 30 316L 2.10E-08 3.58E-05

F00482929, COL 3 Inner Shell Y 23,985 30 316L 2.10E-08 5.04E-04

FC0051206, Bearing, Angular Contact Y 485 30 316L 2.10E-08 1.02E-05

FC0051206, Bearing, Angular Contact Y 485 30 316L 2.10E-08 1.02E-05

F10039975, Ring, Bearing Retaining Y 1,716 30 316L 2.10E-08 3.60E-05

FC0045055 alt 46 Fglass TAPE N - 30 Fglass 2.30E-07 0.00E+00







F00482943 (total for 19 instances) N - 30 316L 2.10E-08 0.00E+00



FC0006127 (6 instances) N - 30 316L 2.10E-08 0.00E+00


F09079610, Core Slice Bore col 3 N - 30 316L 2.10E-08 0.00E+00

F09077587 (6 instances) N - 30 316L 2.10E-08 0.00E+00

F09077586 (6 instances) N - 30 316L 2.10E-08 0.00E+00

F09077585 (6 instances) N - 30 316L 2.10E-08 0.00E+00


F00482932 N - 30 316L 2.10E-08 0.00E+00

F00482933 (8 instances) N - 30 316L 2.10E-08 0.00E+00

F00482934 Y 2,369 30 316L 2.10E-08 4.97E-05

F00482935 Y 383 30 316L 2.10E-08 8.04E-06

F00482936 Y 1,310 30 316L 2.10E-08 2.75E-05

F00482937 (2 instances) Y 2,121 30 316L 2.10E-08 4.45E-05

F00482939 (2 instances) Y 2,306 30 316L 2.10E-08 4.84E-05

F00482921 Y 2,407 30 316L 2.10E-08 5.05E-05

Antiproton Stopping Window Y 507 Kapton 1.00E-06 5.07E-04

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


DS Vacuum:Contributes

to Outgassing

Outgassing

Area temperature material

10 hour

outgassing

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)

Col 5 (this needs to be updated with Poly loads in the COL5 outgassing. ) 1.03E-03

F10043611, Shim, Ball Transfer qty = 4 Y 37 30 316L 2.10E-08 7.72E-07

F00482953 Shell Weldment -

F00482918 Flange COL 1 Shell Y 2,467 30 316L 2.10E-08 5.18E-05

F00482919 End Plate COL 1 Shell Y 2,119 30 316L 2.10E-08 4.45E-05

F00482954 Col 5 Shell Y 24,158 30 316L 2.10E-08 5.07E-04

F10042168 Ring, Insert Locking Y 839 30 316L 2.10E-08 1.76E-05

F100482956 Insert, COL 5 Y 4,937 30 HDPE 8.00E-08 3.95E-04

F00482955 Housing, Ball Transfer, qty = 4 Y 322 30 316L 2.10E-08 6.76E-06

FC0051240, Ball Transfer, qty = 4 Y 322 30 316L 2.10E-08 6.76E-06

DS Bore Heaters 12903.2 Polyamide 1.00E-06 1.29E-02

From Tablea 1,2 & 3 of docdb 1439:

IPA surface Area 43,000 HDPE 8.00E-08 3.44E-03

OPA surface Area 325,000 HDPE 8.00E-08 2.60E-02

TSd Absorber 11,000 HDPE 8.00E-08 8.80E-04

Tracker

Calorimeter - 2 Planes 5.89E-02

Calorimeter, One Plane of 2

Body 1, Alum Frame Y 30,020 AL 3.22E-08 9.67E-04

Bodies 2 to 69, Supports Y 18,463 AL 3.22E-08 5.95E-04

Bodies 117804 to 117891, R410a tubes Y 13,317 316L 2.10E-08 2.80E-04

Bodies 117892 to 117897, Fluorinert tubes Y 67,008 316L 2.10E-08 1.41E-03

Body 117898, alum disk Y 10,968 AL 3.22E-08 3.53E-04

Body 117802, G10 disk Y 26,952 G10 9.00E-07 2.43E-02

Body 117803, alum disk Y 23,274 AL 3.22E-08 7.49E-04

E Box Frame, Alum and cards Y 20,008 AL 3.22E-08 6.44E-04

Crystals, QTY = 674 200mm lg, 34 mm square Y 198,911 tyvek 1.05E-09 2.09E-04

F10039856, muon beam stop assembly -

F10045958, External Absorber Y 114,661 HDPE 8.00E-08 9.17E-03

F10045871, US internal absorber Y 54,087 HDPE 8.00E-08 4.33E-03

F10045872, DS internal absorber Y 37,733 HDPE 8.00E-08 3.02E-03

F10045919, MSB end plug Y 15,275 HDPE 8.00E-08 1.22E-03

F10045920, Mid internal absorber 1 Y 32,544 HDPE 8.00E-08 2.60E-03

F10045921, Mid internal absorber 2 Y 84,728 HDPE 8.00E-08 6.78E-03

F10046858, tube weldment , MBS n -

F10043457, Trunion socket assy left n -

F10043460, bracket trunion assy left Y 693 30 316L 2.10E-08 1.45E-05

F10043462, insert Y 83 30 Bronze 2.10E-08 1.74E-06

F10043465, cover Y 314 30 316L 2.10E-08 6.59E-06

F10043459, trunion socker assy, rt n -

F10043461, bracket trunion assy rt Y 693 30 316L 2.10E-08 1.45E-05

F10043462, insert Y 83 30 Bronze 2.10E-08 1.74E-06

F10043465, cover Y 314 30 316L 2.10E-08 6.59E-06

-

-

F10045841 middle tube support y 56,489 30 316L 2.10E-08 1.19E-03

F10045842 U tube support y 122,744 30 316L 2.10E-08 2.58E-03

F10045839 DS tube support y 45,727 30 316L 2.10E-08 9.60E-04

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


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:


SS bore gas load 1.74E-02

5%

TS-DS interface area gas load 7.31E-03

2%

Feed Thru Gas Load 0

0%Colimator Gas Load 2.28E-03

1%

IPA, OPA a,d Absorber 3.03E-02

10%

Tracker 8.00E-0225%

Calorimeter 5.89E-0218%

MBS 3.19E-0210%

Bore Heaters 1.29E-02

4%

unallocated 7.90E-0225%

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):


• 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:


• 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


MOLFLO+ Run for baseline configuration:

PS+TSd 1 pump with Baffle and valve


MOLFLO+ Run for baseline configuration:

Upstream Muon Beamline Vacuum Volume


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

outgassing 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:


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


MOLFLO+ run for Downstream (TSd+DS) design

configuration:


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

Pressure along a facet along the length of the detector solenoid.

0 is at the TSd100 is at the IFB

Clearly shows pressure gradient along bore due to tracker and calorimeter.

P at TSU = 7.84 x 10-5 mbarP 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.


Interfaces:

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

interface between the Muon beamline vacuum and every

other 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…….


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

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.


Layout of the Remote Handling Room:


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 or outside depending on radiation safety input.

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


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:


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

work in progress (these dimensions not used in calcs yet):


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.


Initial Evacuation Criteria:

• Requirements provide a time constraint on the evacuation to

operating 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.


Simultaneous Pump-Down

of the Upstream and Downstream ends:


0.10

1.00

10.00

100.00

1000.00

0 100 200 300 400 500 600 700

A

b

s

o

l

u

t

e

P

r

e

s

s

u

r

e

,

t

o

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

of the Upstream and Downstream ends:


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 of oil (described next) 150 microns.

0.01

0.10

1.00

10.00

100.00

1000.00

0 100 200 300 400 500 600 700

A

b

s

o

l

u

t

e

P

r

e

s

s

u

r

e

,

t

o

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


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


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.


Estimate of the Oil Back streaming

in the Upstream (PS+TSu) and Downstream (TSd+DS):


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

Diffu

sio

n P

um

p O

il Lost to

Vessel In

terior

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

of plain mineral oil is less than a shot glass of oil for 3 years

operation.

• 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.



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

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.


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


Diffusion Pump Oil Quality Monitoring

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

oxygen 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

operational errors worked well on KTeV to maintain diffusion

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


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


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.


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.


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


• 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

outgassing 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:


Deliverable Vessels for the Muon Beam Line:


• 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:


• 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:


• 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 over 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.


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.


Thin Windows – Beam Exit Window on PS End Cap:


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:


Per FESHM 5033.1& TM-1380: titanium


Diameter, mm 558.8

Diameter, inches 22



Material Ti6%Al4%V





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







qa^4/Et^4 125012.72

K1*(y/t) + K2*(y/t)^3 125012.72

difference 0.000


t/2 0.0090


Thin Windows – Extinction Window on PS End Cap:


Mu2e Extinction Window:Per FESHM 5033.1& TM-1380: titanium


Diameter, mm 152.4

Diameter, inches 6



Material Ti6%Al4%V





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







qa^4/Et^4 116165.85

K1*(y/t) + K2*(y/t)^3 116165.85

difference -0.001


t/2 0.0025


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


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

Anti Proton Stopping Window at COL 3Minimum thickness and diameter from Mu2e Docdb 3179

Per FESHM 5033.1& TM-1380: S200FH Beryllium S200FH Beryllium


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:


Anti Proton Stopping Window at COL 3Per 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:


STM Window on the IFBPer FESHM 5033.1& TM-1380: Titanium Grade 2


Diameter, mm 200

Diameter, inches 7.87


Radius of Window, a (inches) 3.937

Material Grade 2





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





Check if Stress from Geometry > Material Allowable Stress thickness ok


qa^4/Et^4 36.46

K1*(y/t) + K2*(y/t)^3 36.46

difference 0.000


t/2 0.0250


Thin Windows – IFB Window with Kapton or Mylar:


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.


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.


Interlocks:

• Plan is to use manually controlled equipment

– No automated pump down

– Ability to connect to ACNET for remote operation or manual

operation.

• 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.


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.


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.


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.


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)


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


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.


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

outgassing. 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

outgassing. Yes

Loss of a mechanical pump



close. Diffusion pump heater(s) are

deenergized. Mechanical Pumps

continue.

Vacuum System goes to static mode.

Absolute pressure rises due to

outgassing. 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


Controls system drops beam permit.



close. Diffusion pump heater(s)

deenergize.

Diffusion pumps isolated with valves,

heaters deenergized. Mechanical

pumps continue to operate. Yes

Large, instantaneous vacuum window

failure


Controls system drops beam permit.



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


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


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.


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


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).


Back-Up Material (FEM Risk Assessment):

• Fermilab Engineering Manual (FEM) Risk Assessment:


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)


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


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.


Back-Up Material (Equipment Catalog Cuts and

Performance Curves – Mechanical Pumps):

• Equipment Catalog Cuts:



Performance Curves – Diffusion Pumps):


Back-Up Material (Equipment Performance Curves –

Upstream Diffusion Pump and Blower/Mechanical Pump):



Performance Curves – Diffusion Pump Oil):


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?


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


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

Feb 9, 201787

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

Feb 9, 201788

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

Feb 9, 201789

Documents

Mu2e Muon Beamline Vacuum Overview - INDICO-FNAL (Indico)...2017/02/09 · TSU Closure Cylinder Y 11,293 30 316L 2.10E-08 2.37E-04 Colimator 1, col 1 43,990 4.15E-04 F10043611 Shim,