1 Fulvio TESSAROTTO the new RICH beam pipe the new RICH beam pipe - pipe production, gluing and...

1Fulvio TESSAROTTO

the new RICH beam pipe

- pipe production, gluing and tests

- measurement and removal of the old pipe

- fixation system

- installation of the new pipe - characteristics of the new pipe

COMPASS TB meeting, CERN, 12/04/2012

Fulvio Tessarotto

2Fulvio TESSAROTTO COMPASS TB meeting, CERN, 02/02/2012

Slide from the last TB:

Issue status

Removal of presently used pipe Extremely difficult behind the mirrors

Material for the thin pipe 5 layer aluminized Mylar, 0.6 ‰ X

Geometry 2 pipes 100 mm diam., 1570 mm long

Gas He, few l/h, 15 mbar overpressure

End caps alum. Mylar glued on Al microflanges

Fixation system Thin stainless steel wire ropes

Extremely difficult behind the mirror wall:

still to be defined


tubes, microflanges, gluing tests

weight = 15 g

4Fulvio TESSAROTTO

Simulations for the new pipe

max = 0.1 Mpa,yield strength = 85 MPaCOMPASS TB meeting, CERN, 12/04/2012


half-pipe He leak tests

Measured leak, including connections: 0.5 ml/h

6Fulvio TESSAROTTO

“Safety is the first of our priorities”

- RICH is a “confined space”: access is allowed to authorized persons only

- Authorization requires a confined space formation course and a medical certification

- New procedure: CERN asks for medical certification to be provided by the Institutes.- Inside the RICH we needed a scaffolding: the old scaffolding is not complying to the rules.- The new scaffolding can only be mounted by authorized people.- The authorisation requires ….

1) a general CERN confined space course was organized and people sent to attend it

2) a medical check and certification protocol was defined, agreed upon and applied in Trieste

3) the activity inside the RICH was defined in detail and an access protocol was produced

4) the supervisor was changed

5) special exception to allow access for radioprotection experts, scaffolding responsible, etc.

6) a scaffolding was borrowed / built and certified by the responsible in Clean Area

7) authorization to mount the scaffolding by ourselves was obtained

8) authorization to use the scaffolding (after check) with a use protocol was provided

9) … 10) …

All involved persons have been extremely collaborative!

Firenze, 22/03/2012

7Fulvio TESSAROTTO

RICH opening, old pipe removal1) Radiation level: < 0.2 μSv/h2) Surveying of the old pipe3) Large scaffolding installation4) Small scaffolding installation5) Removal of the old pipe4) Mirrors surveying


8Fulvio TESSAROTTO

After the removal of the old pipe

- We confirmed it is not possible to access the area downstream of the mirrors

- We decided to change the fixation system and the gas pipes to reduce the material

1) We prepared two beam pipes of 1.6 m and tested them: measured leak rate: 0.5 ml/h

2) We decided to produce a unique pipe by gluing two halves on 1.6 m

3) The vertical middle gluing needed a special microflange and a system for vertical operation

4) We continued to put pressure on Lamina, despite the denials, to try producing a 3.2 m tube

5) One 3.5 m long tube arrived in Trieste just in time.

6) The microflanges and the system for gluing were ready: the long pipe was glued and

7) Tested together with the “Tygon” pipes and plastic strips for gas connection: 0.6 ml/h

8) Both long pipes (single piece and two-halves shipped to CERN)

9) We checked that two suspensions are enough (pipe rigidity better than expected)

Two fixation points are enough



gluing end-caps on the single pipe


Careful packaging


And transport

12Fulvio TESSAROTTO

Preparation for the new pipe10) Putting in place the top fixation systems was challenging but successful

11) Dummy flanges positioned using a laser system

12) Pipe introduced in the RICH and put in place

13) Surveying to check the position found several millimeter offsets

14) Position partially corrected and fixation system tensioned at 2 kg



Pre-alignment of pipe holders


the new pipe inside the RICH


The polycarbonate suspension ring


New fixation system and gas pipes


Pipe specificationsInner diameter: 100.0 mm (+0.0-0.1)Thickness: 140 μm Length: 3140 mmMaterial: Mylar (PET) + 1 μm Al

Single pipe, front and rear window:same material: 140 μm Mylar + 1 μm AlMicroflanges: “F” shape Al, 0.5 mm thick

Upstream microflange acts as holder,Downstream holder at 80 cm from edge,Policarbonate 8mm x 8mm + 2 nylon screws

Fixation via stainless steel microwire ropes:4 ropes (90 degrees) per holder,1 x 7 wires 90 μm diam. (limit = 9 kg)+ 10 μm nylon coating, tensioning: 2 kg,thermal expansion +- 2 mm, equiv. 1 kg

Adjustement and tensioning microsystems placed out of the acceptance


Upstream fixation and gas connections

Total amount of materialin the acceptance:

Fe (8 m microwire ropes): 5 gAl ( 2 m pipe + microfl.): 60 gMylar: 180 gPolycarbonate (fixation): 20 gEpoxy: 6 gCu: 0.5 gTygon: 5 gNylon: 4 g

Old gas pipes: 6x4 mm stainless steel tubes, new pipes: 6x5 mmAl pipes (10 times less X0)


Measurement and adjustment


position regulation and surveying


Material budget

actual pipe material budget: (0.15 mm / 17.6 mm) 8.523 ‰ X0

goal for the material budget of the new pipe: 10% actual = 0.852 ‰ X0

5 layers of 27 μm thick Mylar : (0.135 mm / 287 mm) 0.470 ‰ X0

5 layers of 200 nm thick Al coating: (1.0 μm / 89 mm) 0.011 ‰ X0

4 layers of 6 μm thick Mylar glue: (24 μm / 280 mm) 0.086 ‰ X0

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total material budget for orthogonal crossing: 0.567 ‰ X0

total material budget for parallel crossing (r < 42 mm): 2.26 ‰ X0

parallel crossing (42 mm < r < 49 mm): 1.9 % X0

6 mrad particle crossing the pipe (old value = 1.4 X0) 9 % X0

The contribution from end caps, fixation rings, gas connections has been minimized


time schedule

RICH opening February 21

Scaffolding mounted February 24

Old pipe measurement March 6

Removal of the old pipe March 7

Mirror measurement March 16

Installation of the new pipe April 5

He leak test April 17

Scaffolding dismounting April 18

RICH closing April 19 or April 25

1 Fulvio TESSAROTTO the new RICH beam pipe the new RICH beam pipe - pipe production, gluing and...

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