Construction of PVC Extrusions for NO n A Near and Far Detectors

Sarah Phan-Budd, TIPP 2011 1

Construction of PVC Extrusions for NOA Near and Far Detectors

Sarah Phan-BuddArgonne National Lab

On Behalf of the NOA Collaboration


The NOA Experiment

• NuMI Off-Axis e Appearance Experiment

• 14kT Far Detector, 14mr off-axis, in Ash River MN– L=810 km E~=2GeV

• 220T Near Detector, at FNAL• Run for 6 years

– 3 years each of normal and reverse horn current running

• Goals

– Measurement of 13

– Determination of mass hierarchy via MSW effect

– Begin to localize CP

– Precise Measurement of sin2(223)

NOA FD Location

MINOSFD Location(On-axis)

NOA ND Location(FNAL)


The NOA Detectors

• FD: 65% Active Volume, 928 planes

• Planes consist of PVC extrusions w/15% TiO2 – Alternate vertical &

horizontal orientation

• Liquid Scintillator• PVC cell for primary

containment• Wavelength shifting

fiber• Avalanche Photodiode • Low noise amplifier

68 m

3.87cm

To 1 APD pixel

W D

typicalchargedparticle

path

L

To 1 APD pixel

W D

typicalchargedparticle

path

L 15.6m

6.00 cm


Near Detector on the Surface (NDOS)4

• Full test of construction techniques to create a working prototype near detector– PVC Extrusions – Module construction– Block construction– Electronics and Outfitting– DAQ and software

• Finished Winter/Spring 2010-2011• At the intersection of the FNAL NuMI and

Booster beams• Run Goals:

– Exercise calibration scheme– Benchmark MC– Demonstrate electron neutrino selection,

and cosmic and other background suppression

– Physics results


Creating PVC Extrusions for the Detectors

• Creating physics quality extrusions for the detectors has presented a number of challenges

• This talk covers:– PVC Resin and

Powder– Extruding – Quality Control


PVC Resin and Powder

• Created a custom PVC Resin for – NO27

• Designed with physics needs in mind– higher light yield: Use Anatase rather than Rutile

TIO2

– Maintain good tensile properties

PVC Extrusions and Light Yields

0.87

1.01

0.75 0.80 0.85 0.90 0.95 1.00 1.05

N24P(4/07)

N27(4/07)

Relative Light Yield

anatase

rutile


50

60

70

80

90

100

400 410 420 430 440 450 460 470 480 490 500

WAVELENGTH (nm)

NOVA-27

BASELINE

Reflectivity of Anatase compared to Rutile

Nova-27: anatase

Rutile sample from extrusion tests in 2005

RE

FL

EC

TIV

ITY

(%

)


Creating PVC Extrusions

• NO extrusions are made using a specially designed die and a designed extrusion line

• A prototype die was used and tested on NDOS extrusions

• This experience was used to create a final die for far detector extrusions


Prototype Extruder and Die

• Extruder– Krauss-Maffei (KMD-60) Twin

Screw– 60mm is the diameter each

screw• Extruder PVC output ~ 550

lbs/hour

Assembled Die with Heater Plates

Disassembled Die


Many Lessons Have Been Learned to Avoid this Outcome


Far Detector Extrusions

New KMD-90/32

Twice the throughput

New Dies, Calibrators and Cooling Tanks


Extrusion Quality Control

• A number of quality control tests are performed to ensure physics quality extrusions

• Measured properties• Mechanical: drop dart, tensile tests, pressure and

vacuum tests, creep• Reflectivity• Dimensional: camera, flatness measurements,

caliper measurements


QC Process

Camera measurements on every 6’’ sample

Dart Test

On every other 6’’ sample

Pressure Test

Reflectivity

On every other 6’’ sample

6” sample Full length extrusion

Isolated cell vacuum testDone on every extrusion

Tensile tests performed weekly from samples taken once per day. Test performed at ANL.

Creep samples created bi-weekly.

Sarah Phan-Budd, TIPP 2011 14 14

Pressure Tester

• Pressure tester pressurizes alternate cells.

• This tests internal webs and outer walls


Vacuum Tester

Vacuum test checks for Web knitting/buckling- for entire extrusion


Drop Dart Test

• Prototype version show (left)

• Production version (right)

• Fully automated testing Auto clamping and internal anvil should enhance consistency of results


Drop Dart Impact Results

Ductile and brittle failures along with separation along knit line

Brittle failure / fracture through “continuous” material

Relatively deep and shallow dimples prior to failure: good and poor ductility


Camera: Dimensional Measurements

• OGP metrology machine measures:– Flatness

(straightness)– web thickness/

location/ perpendicularity

– wall thickness– radii– Overall and individual

cell height– Width


Reflectivity

• Table top spectrophotometer – “non-specular” mode – Extended range to 360 nm

• Cutting fixture allows QC measurements of interior

• All measurements done at the Extruder


Light Yield

'XTR' barcodes

0

1

2

3

4

5

6

7

8

9

0 50 100 150 200 250 300 350 400 450

Barcode Number

% o

f P

ho

ton

s

'XTR' barcodes

8485868788899091929394

0 50 100 150 200 250 300 350

REFL

ECTI

VITY

(%)

SAMPLES

500 nm

500 nm

82838485868788899091

0 50 100 150 200 250 300 350

REFL

ECTI

VITY

(%)

SAMPLES

420 nm

420 nm

15

16

17

18

19

20

21

22

0 50 100 150 200 250 300 350

REFL

ECTI

VITY

(%)

SAMPLES

360 nm

360 nm

Reflectivity measurements are taken at wavelengths from 340nm to 470nm and these are used to create a relative light yield using MC simulation


Mechanical Properties

• Modulus, Yield, Ultimate stress come from ASTM tensile test-daily at ANL

• Creep samples started every 2 weeks• Tensile test results can indicate knitting problems


Conclusions

• The detector is created using a novel technology of extruded PVC tubes filled with liquid scintillator

• In order to create physics quality extrusions, several new pieces had to be developed– New resin– Extruder dies and extruding technique– Quality control procedure

• Techniques have been prototyped and tested on the NDOS and extrusions are now being created for the far detector


Backup


NOvA Prototype Die: Disassembled


A few of the Key Findings from R&D Experience

• PVC resin must be “Extrudable” in the Production Die– If PVC resin extrudes well in smaller dies or large dies with

thinner walls it does not follow that the same PVC will extrude in the Nova die

• NOvA dies require powerful extruder– Big extruders have long heating volumes

• Proper heating of PVC powder before it enters die– Residence time is key once inside the die

• PVC will decompose if exposed to high temperatures• Burning & sticking to die• Some narrow openings will get clogged

– Long distance to reach outside cells – Thick walls & webs require higher mass flow

• Extruding machine should operate at ~80% max capacity– Highest quality product


PVC Quality Control

QC DB

Reflectometer

Non-DB ready Data file

DB interface parses data and inputs into DB

Optical inspection system

Labview operator interface creates DB ready file

Impact

Labview operator interface creates DB ready file

Hand entered quantities

PVC, vacuum, weight, straightness, pressure

Non-DB ready Data file


Tensile Test Results

Typical Bad Results•Low total elongation, with lots of scatter.•Yield stress at or below 6000 psi.

Typical Good Results•Plots are consistent and very similar•Large total elongation, typically all over 30%, many going to 50%.•Yield Stress over 6000 psi.


crack initiated here

underside crater

Knitting problem

Construction of PVC Extrusions for NO n A Near and Far Detectors

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