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Page 1: Update on straw creep measurementsmu2e.phy.duke.edu/talks/2015-08-31_creep.pdf · 8/31/2015  · Straw end position vs time (ref: doc#2277 & 2084 for setup) on on 08/31/15 550 gm

Update on straw creep

measurements

Chiho Wang, Seog Oh

Duke University

(doc 2484)

Page 2: Update on straw creep measurementsmu2e.phy.duke.edu/talks/2015-08-31_creep.pdf · 8/31/2015  · Straw end position vs time (ref: doc#2277 & 2084 for setup) on on 08/31/15 550 gm

“Fixed Tension” Creep Measurement

• PPG straws: 155cm long, 5mm ID, 18 um wall (6μm Al

coated Mylar outer layer + 6μm Al+Au coated Mylar inner

layer + 6um polyester adhesive).

• Straw properties:

Spring constant k=1.4cm/kg

Mylar thermal expansion = 1.7E-05/°C (DuPont)

Mylar humidity expansion = 6.0E-6/%(RH) (DuPont)

• Initial condition: 550gm weight + 18 psi ~ 800gm tension.

• After 120 days: changed to 550gm weight + 0 psi.

• After 1150 days: changed to 50gm weight

08/31/15 Chiho Wang, Seog Oh 2

Page 3: Update on straw creep measurementsmu2e.phy.duke.edu/talks/2015-08-31_creep.pdf · 8/31/2015  · Straw end position vs time (ref: doc#2277 & 2084 for setup) on on 08/31/15 550 gm

Straw end position vs time(ref: doc#2277 & 2084 for setup)

Stra

w e

nd

Po

siti

on

Stra

w le

ngt

hen

ing

dir

ecti

on

08/31/15

550 gm tension on 155 cm straw,Creep rate ~ 1.6 μm/day

Chiho Wang, Seog Oh 3

When tension is removed (reduced to 50 gm) it also takes a long time to creep back

Page 4: Update on straw creep measurementsmu2e.phy.duke.edu/talks/2015-08-31_creep.pdf · 8/31/2015  · Straw end position vs time (ref: doc#2277 & 2084 for setup) on on 08/31/15 550 gm

“Fixed Length” Creep Measurement

• Glue straws on a support frame (120cm) with tensions:

300gm, 400gm, 500gm, 600gm.

• Measure straw tension by resonant frequency as a

function of time.

08/31/15

PrecisionFunction generator

Frequency Counter

Weight

SpeakerMagnet Support Frame

Straw

Chiho Wang, Seog Oh 4

Page 5: Update on straw creep measurementsmu2e.phy.duke.edu/talks/2015-08-31_creep.pdf · 8/31/2015  · Straw end position vs time (ref: doc#2277 & 2084 for setup) on on 08/31/15 550 gm

Tension change vs time

Linear Fit (150 days and later)

08/31/15(corrected for temperature & humidity variation)

Chiho Wang, Seog Oh 5

Page 6: Update on straw creep measurementsmu2e.phy.duke.edu/talks/2015-08-31_creep.pdf · 8/31/2015  · Straw end position vs time (ref: doc#2277 & 2084 for setup) on on 08/31/15 550 gm

Temperature & Humidity variation

08/31/15 Chiho Wang, Seog Oh 6

Page 7: Update on straw creep measurementsmu2e.phy.duke.edu/talks/2015-08-31_creep.pdf · 8/31/2015  · Straw end position vs time (ref: doc#2277 & 2084 for setup) on on 08/31/15 550 gm

Corrections due to T & H variation

08/31/15

Humidity expansion coefficient = 7.6E-6/%Thermal expansion coefficient = 1.7E-5 (Mylar) – 2.35E-5 (Al Frame) = -6.5E-6/°C

Chiho Wang, Seog Oh 7

Page 8: Update on straw creep measurementsmu2e.phy.duke.edu/talks/2015-08-31_creep.pdf · 8/31/2015  · Straw end position vs time (ref: doc#2277 & 2084 for setup) on on 08/31/15 550 gm

Fractional Tension change vs time

Linear Fit (150 days and later)

08/31/15(corrected for temperature & humidity variation)

Chiho Wang, Seog Oh 8

Page 9: Update on straw creep measurementsmu2e.phy.duke.edu/talks/2015-08-31_creep.pdf · 8/31/2015  · Straw end position vs time (ref: doc#2277 & 2084 for setup) on on 08/31/15 550 gm

Slope

• Fractional tension change is almost the same irrespective

of their initial tensions.

08/31/15

Initial Tension (T0) ∆T/T0/day-

300 g - 8.8E-5 ± 0.1E-5

400 - 9.5E-5 ± 0.1E-5

500 - 9.8E-5 ± 0.1E-5

600 - 9.8E-5 ± 0.1E-5

Chiho Wang, Seog Oh 9

Page 10: Update on straw creep measurementsmu2e.phy.duke.edu/talks/2015-08-31_creep.pdf · 8/31/2015  · Straw end position vs time (ref: doc#2277 & 2084 for setup) on on 08/31/15 550 gm

Fractional Tension change vs time

Exp Fit (c0*e-c1*t+c2) (50 days and later)

08/31/15(corrected for temperature & humidity variation)

Chiho Wang, Seog Oh 10

Page 11: Update on straw creep measurementsmu2e.phy.duke.edu/talks/2015-08-31_creep.pdf · 8/31/2015  · Straw end position vs time (ref: doc#2277 & 2084 for setup) on on 08/31/15 550 gm

C2 in Exp Fit (c0*e-c1*t+c2)

08/31/15

Initial Tension (T0) C2

300 g 0.556 ± 0.001

400 0.539 ± 0.001

500 0.543 ± 0.001

600 0.536 ± 0.001

Chiho Wang, Seog Oh 11

Page 12: Update on straw creep measurementsmu2e.phy.duke.edu/talks/2015-08-31_creep.pdf · 8/31/2015  · Straw end position vs time (ref: doc#2277 & 2084 for setup) on on 08/31/15 550 gm

Fractional Tension change vs time

Exp Fit (c0*e-c1*t+0) (150 days and later)

08/31/15(corrected for temperature & humidity variation)

Chiho Wang, Seog Oh 12

Page 13: Update on straw creep measurementsmu2e.phy.duke.edu/talks/2015-08-31_creep.pdf · 8/31/2015  · Straw end position vs time (ref: doc#2277 & 2084 for setup) on on 08/31/15 550 gm

C1 in Exp Fit (c0*e-c1*t+0)

08/31/15

Initial Tension (T0) C1 (day-1)

300 g 15E-5 ± 0.2E-5

400 17E-5 ± 0.1E-5

500 17E-5 ± 0.1E-5

600 17E-5 ± 0.1E-5

Chiho Wang, Seog Oh 13

Page 14: Update on straw creep measurementsmu2e.phy.duke.edu/talks/2015-08-31_creep.pdf · 8/31/2015  · Straw end position vs time (ref: doc#2277 & 2084 for setup) on on 08/31/15 550 gm

Exp Fit (c0*e-c1*t+c2) 6-year projection

08/31/15(corrected for temperature & humidity variation)

Chiho Wang, Seog Oh 14

Page 15: Update on straw creep measurementsmu2e.phy.duke.edu/talks/2015-08-31_creep.pdf · 8/31/2015  · Straw end position vs time (ref: doc#2277 & 2084 for setup) on on 08/31/15 550 gm

Exp Fit (c0*e-c1*t+0) 6-year projection

08/31/15(corrected for temperature & humidity variation)

Chiho Wang, Seog Oh 15

Page 16: Update on straw creep measurementsmu2e.phy.duke.edu/talks/2015-08-31_creep.pdf · 8/31/2015  · Straw end position vs time (ref: doc#2277 & 2084 for setup) on on 08/31/15 550 gm

Fractional Tension

Exp Fit (c0*e-c1*t+0) 6-year projection

08/31/15(corrected for temperature & humidity variation)

Chiho Wang, Seog Oh 16

Page 17: Update on straw creep measurementsmu2e.phy.duke.edu/talks/2015-08-31_creep.pdf · 8/31/2015  · Straw end position vs time (ref: doc#2277 & 2084 for setup) on on 08/31/15 550 gm

Linear Fit 6-year projection

08/31/15(corrected for temperature & humidity variation)

Chiho Wang, Seog Oh 17

Page 18: Update on straw creep measurementsmu2e.phy.duke.edu/talks/2015-08-31_creep.pdf · 8/31/2015  · Straw end position vs time (ref: doc#2277 & 2084 for setup) on on 08/31/15 550 gm

Fractional Tension

Linear Fit 6-year projection

08/31/15(corrected for temperature & humidity variation)

Chiho Wang, Seog Oh 18

Page 19: Update on straw creep measurementsmu2e.phy.duke.edu/talks/2015-08-31_creep.pdf · 8/31/2015  · Straw end position vs time (ref: doc#2277 & 2084 for setup) on on 08/31/15 550 gm

Assuming (c0*e-c1*t+0)

Equivalent time shift by initial tension

08/31/15 Chiho Wang, Seog Oh 19

Page 20: Update on straw creep measurementsmu2e.phy.duke.edu/talks/2015-08-31_creep.pdf · 8/31/2015  · Straw end position vs time (ref: doc#2277 & 2084 for setup) on on 08/31/15 550 gm

Summary

• Summary:

Extrapolation for fractional tension after 6 years is:

o ~0.45 from a linear fit

o ~0.47 from an exponential to 0 fit (c0*e-c1*t+0).

o ~0.54 from an exponential to const. fit (c0*e-c1*t+c2)

No significant change in results since last report. However,

extrapolations are consistently getting better over time.

Fractional tensions continue to scale well and can be used to

estimate creep at other initial tensions.

Weather effect seems averaging out after a long period of time.

Extrapolated results are very similar with or without temperature &

humidity correction.

Will stop taking data, but can resume in the future as needed.

08/31/15 Chiho Wang, Seog Oh 20

Page 21: Update on straw creep measurementsmu2e.phy.duke.edu/talks/2015-08-31_creep.pdf · 8/31/2015  · Straw end position vs time (ref: doc#2277 & 2084 for setup) on on 08/31/15 550 gm

Backup slides

10-year fractional tensions extrapolation.

Raw data without temperature/humidity corrections.

08/31/15 Chiho Wang, Seog Oh 21

Page 22: Update on straw creep measurementsmu2e.phy.duke.edu/talks/2015-08-31_creep.pdf · 8/31/2015  · Straw end position vs time (ref: doc#2277 & 2084 for setup) on on 08/31/15 550 gm

Fractional Tension

Exp Fit (c0*e-c1*t+0) extrapolation

08/31/15(corrected for temperature & humidity variation)

Chiho Wang, Seog Oh 22

Page 23: Update on straw creep measurementsmu2e.phy.duke.edu/talks/2015-08-31_creep.pdf · 8/31/2015  · Straw end position vs time (ref: doc#2277 & 2084 for setup) on on 08/31/15 550 gm

Raw data Fractional Tension

Exp Fit (c0*e-c1*t+0) extrapolation

08/31/15(Without correction for temperature & humidity variation)

Chiho Wang, Seog Oh 23

Page 24: Update on straw creep measurementsmu2e.phy.duke.edu/talks/2015-08-31_creep.pdf · 8/31/2015  · Straw end position vs time (ref: doc#2277 & 2084 for setup) on on 08/31/15 550 gm

Fractional Tension

Linear Fit extrapolation

08/31/15(corrected for temperature & humidity variation)

Chiho Wang, Seog Oh 24

Page 25: Update on straw creep measurementsmu2e.phy.duke.edu/talks/2015-08-31_creep.pdf · 8/31/2015  · Straw end position vs time (ref: doc#2277 & 2084 for setup) on on 08/31/15 550 gm

Raw data Fractional Tension

Linear Fit extrapolation

08/31/15(Without correction for temperature & humidity variation)

Chiho Wang, Seog Oh 25

Page 26: Update on straw creep measurementsmu2e.phy.duke.edu/talks/2015-08-31_creep.pdf · 8/31/2015  · Straw end position vs time (ref: doc#2277 & 2084 for setup) on on 08/31/15 550 gm

Tension change vs time

Linear Fit (after 100 days)

08/31/15(without correction for temperature & humidity variation)

Chiho Wang, Seog Oh 26