1. Neil Dixon PH/DT Dubna 30/11- 4/12 '09
Straw manufacturing
Base material.
Metallisation.
Tube manufacture, Quality Control.
Storage.
Neil Dixon PH/DT Dubna 30/11- 4/12 '09

2. Base material PET (Polyethylene terephthalate) (C10H8O4)n Background:
The material sourcing and coating was in the hands of Fraunhofer.
We were recently informed that the base material is no longer available, this prompted a search for suppliers.
Sourcing new material could require a full long term test period.
Neil Dixon PH/DT Dubna 30/11- 4/12 '09

3. Material specifications
PET (Polyethylene terephthalate) (C10H8O4)n
The thickness of the material is 36 micrometers +/- 2 µm
Tensile strength should be close to N/mm² ( MD )
230 N/mm² ( TD )
Density g/cm³
Good permeation properties.
Good metal bonding properties.
Good epoxy adhesion properties.
The last points are qualified by tests at CERN
Neil Dixon PH/DT Dubna 30/11- 4/12 '09

4. Neil Dixon PH/DT Dubna 30/11- 4/12 '09
Current situation
Current material:
Hostaphan® GN 4600: one side treated, supplied by Mitsubishi Polymers.
Other candidates:
Melinex and Mylar by Dupont Teijin films.
Proposals by Fraunhofer:
Excell 523 both sides coated. (Toray Saehan Inc.)
Lumirror (Toray / appears to be out of production).
Direct Contact with Mitsubishi Polyester Film GmbH :
Hostaphan® GN 4600 no longer manufactured in Europe;
but
Available from the USA under the name Hostaphan® 460L chemically primed on 1 side
Also available Hostaphan® 460L Coated / chemically primed on both sides
Neil Dixon PH/DT Dubna 30/11- 4/12 '09

5. Neil Dixon PH/DT Dubna 30/11- 4/12 '09
Evaluation of samples
Several tests are being run in parallel at CERN.
Coating and adhesion quality. PH/DT A. Braem, C. David.
Electro microscope observations. EN/MME M. Scheubel and S. Sgobba
Permeation tests. TE/VSC F. Bouvier, P. Chiggiato, M. Taborelli, W.Vollenberg
Bonding tests. ( straw tube to PEI ultem® end piece)
Neil Dixon PH/DT Dubna 30/11- 4/12 '09

6. Coating and adhesion quality
The adhesion of the metallised coating to the PET substrate is good.
Preliminary tests at CERN show that samples coated on both treated and untreated surfaces show similar adhesion properties.
More tests are planned on some of the alternative PET
Neil Dixon PH/DT Dubna 30/11- 4/12 '09

7. Electro microscope observations
Ongoing observations; some early results:
Samples as follows:
Fraunhofer coated on treated side (sputtering)
CERN coated on treated side (evaporation)
CERN coated on untreated side (evaporation)
Neil Dixon PH/DT Dubna 30/11- 4/12 '09

8. Electro microscope observations Magnification 1000 X
Fraunhofer treated CERN treated
Neil Dixon PH/DT Dubna 30/11- 4/12 '09

9. Electro microscope observations Magnification 1000 X
CERN untreated
Neil Dixon PH/DT Dubna 30/11- 4/12 '09

10. Electro microscope observations Magnification 5000 X
Fraunhofer treated CERN treated
Neil Dixon PH/DT Dubna 30/11- 4/12 '09

11. Electro microscope observations Magnification 5000 X
CERN untreated
Neil Dixon PH/DT Dubna 30/11- 4/12 '09

12. Neil Dixon PH/DT Dubna 30/11- 4/12 '09
Preliminary results
The metallisation of the PET appears to be more uniform on the untreated side.
CERN experts in thin film coating, advise to coat the non treated side.
Samples have been requested and are to be prepared at CERN.
Preparation of the samples before evaporation was greatly helped using and anti-static gun.
Neil Dixon PH/DT Dubna 30/11- 4/12 '09

13. Neil Dixon PH/DT Dubna 30/11- 4/12 '09
Permeation
Samples tested:
Naked PET source of which is dubious.
Straw samples as above; substrate dubious.
More recently:
Fraunhofer coated on treated side (sputtering)
CERN coated on treated side (evaporation) C treated
CERN coated on untreated side (evaporation) C untreated
Neil Dixon PH/DT Dubna 30/11- 4/12 '09

14. Neil Dixon PH/DT Dubna 30/11- 4/12 '09
Permeation
BIF= Barrier Improvement Factor
BIF=
π coefficient of permeability of base material
π coefficient of permeability of coated material
Samples with Ultra Sonic weld have permeation factor 2 times worse than naked PET
PET coated with Aluminum shows improvement factor 3 over reference.
PET coated with Cu + Au shows and improvement factor 3 over reference.
A sample well prepared shows an improvement of 6 w.r.t. reference, theory suggests BIF 100 is possible.
Neil Dixon PH/DT Dubna 30/11- 4/12 '09

15. Neil Dixon PH/DT Dubna 30/11- 4/12 '09
Permeation
Results:
Straw samples tested are no worse than recent “untouched” samples.
Samples coated at CERN with a greater thickness of Cu, show an improvement of a factor 10 compared to our best samples; although the tested sample, had a visual “pin hole” effect.
Recent figures that need to be confirmed by a second measurement as the test apparatus is showing a large background.
Neil Dixon PH/DT Dubna 30/11- 4/12 '09

16. Neil Dixon PH/DT Dubna 30/11- 4/12 '09
Permeation
Ongoing tests:
Permeation of naked PET.
Permeation w.r.t. to coating thickness.
Permeation w.r.t. coated side.
Permeation of GN 4600 Vs Excell 532.
Neil Dixon PH/DT Dubna 30/11- 4/12 '09

17. Neil Dixon PH/DT Dubna 30/11- 4/12 '09
Bonding tests
Samples tested:
GN 4600 treated
GN 4600 Un treated
Excell 532 treated.
Peel test clearly demonstrate the effect of the chemical treatment of the PET surface.
Samples bonded with Tra-Bond 2115 on the treated surface, when submitted to a peel test show a catastrophic failure of the PET.
Samples bonded to the untreated surface however show very weak adhesion properties.
Hostaphan GN4600 giving the best results.
Neil Dixon PH/DT Dubna 30/11- 4/12 '09

18. Neil Dixon PH/DT Dubna 30/11- 4/12 '09
Tube manufacture
See S. Movchan “Straw manufacturing and QC” 23 Nov 2009.
A few additions.
Neil Dixon PH/DT Dubna 30/11- 4/12 '09

19. Neil Dixon PH/DT Dubna 30/11- 4/12 '09
Plans
CERN to specify and source the correct PET. (quantity, size and length of rolls)
Fraunhofer to remain as preferred supplier for coating.
CERN to arrange slitting of coated PET.
A clear specification and delivery schedule needs to be agreed with Fraunhofer.
To Include:
General quality control and traceability.
Storage of the PET at all times to be specified. ( %RH; °C )
QC on Cu and Au Thickness, Ω; coating uniformity and measurement techniques.
Neil Dixon PH/DT Dubna 30/11- 4/12 '09

20. Neil Dixon PH/DT Dubna 30/11- 4/12 '09
Plans
Base material:
Supplier to be finalised and order placed.
Metallisation:
Specification to be finalised and coating dates planned.
Tube manufacture:
Another prototype run before final production.
Storage / shipping:
Methods to be designed and approved.
Neil Dixon PH/DT Dubna 30/11- 4/12 '09

21. Neil Dixon PH/DT Dubna 30/11- 4/12 '09
Conclusions:
Much effort is needed before we see our first final straw tube.
Neil Dixon PH/DT Dubna 30/11- 4/12 '09

22. Neil Dixon PH/DT Dubna 30/11- 4/12 '09
Storage
On Nov 23 S. Movchan presented the solution of inflating the straw for storage.
This idea is still in its development stage, as there are many parameters to look at: feasibility, cost, and how far do we carry this idea.
There are advantages and disadvantages as well as feasibility issues that need to be looked at in detail.
It seems that for the early stages following straw manufacturing, the tube should be stored under pressure. ( clean, leak control ).
How far in the assembly process do we keep the straw inflated?
Questions that may only be answered after tests are made.
Neil Dixon PH/DT Dubna 30/11- 4/12 '09

23. Neil Dixon PH/DT Dubna 30/11- 4/12 '09
Metallisation
Following the preliminary permeation results; it is suggested that we look into a thicker metal coating of the PET.
Some DATA:
Radiation length in cm: For our tubes
PET micrometer
Cu nanometer
Au nanometer
Kapton 28.6
From these figures, physics may not be compromised if the Cu thickness is increased ?
Neil Dixon PH/DT Dubna 30/11- 4/12 '09