cryostat assembly, integration and commissioning procedures

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Cryostat assembly, integration and commissioning procedures

M.Olcese

Version: 07 May 2008

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Definitions

• Flanges/plates (from innermost):– MC plate: mixing chamber plate– HEX plate: heat exchanger plate– STILL plate– 4K flange: Inner Vacuum Chamber (IVC) plate– 40K plate– 300K flange: Outer Vacuum Chamber (OVC) plate

• Vessels/screens:– MC screen (upper and lower part)– HEX screen– 4K vessel: IVC vessel– 40K screen– 300K vessel: OVC vessel

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Schematic: cryostat

Main external shielding

300K, 4K vessels and 40K screen

300K, 4K flangesand 40K plate

Lateral STILL lead shield

Internal screens (STILL-HEX-MC)

Lateral STILL lead shield support cradle

Detector

Detector support plate

Internal top lead shield

STILL plate

STILL top lead ring

HEX and MC plates

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Main platform (lower)

1° floor

Main platform (upper)

2° floor

Light platform

Corridorside

ParkingSide of main shielding

Concrete walls

Main rail system

Aux. rail system

Schematic: building and platform

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Scenarios

1. Initial installation:1.1 Installation of 300k-40k-4k plates

1.2 Dry fit of vessels and screens

1.3 Installation of STILL-HEX-MC plates

2. Cryostat commissioning

3. Detector installation

4. Access for maintenance

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General issues

• All the individual items (with few exceptions) can be brought on the main platform for the installation:– from the hut ground floor with the platform in

the side position– Directly from the external corridor using an

auxiliary rail system

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1 Initial installation1.1 installation of top plates/flanges

• The plates are delivered clean and inside plastic bags• The plates are piled up on the main platform (a platform

add-on may be required to reach the 1° floor level)• The main platform is raised• Eye bolts + radial extensions (if needed) will be fixed to

the plates.• The plates are lifted by means of the hoist cable system

and connected to the tie rods/suspensions• It may be convenient to install, along with the plates,

some of the internal components like: sections of the source tube, wire feed-throughs, IVC pumping tube, …

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Main platform

Platform extension

Option 1

Stack of plates in reverse order (4K-40K-300K)

Initial installation 1.1: setting of plates on platform at ground level

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Option 2

Plates set on auxiliary platform from the corridor side

Initial installation 1.1: setting of plates on platform at ground level

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Initial installation 1.1: platform with plates ready for lifting

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Initial installation 1.1: platform reach the 1° floor level

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Initial installation 1.1: 300K-4K flanges and 4K plate are installed in sequence

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Initial installation 1.1: completed

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1 Initial installation1.2 dry-fit of 300K-4K vessels and 40K screen

• Purpose: – check the handling procedure and sign-off of the

cable hoist system– Check vacuum tightness and deformations of OVC

and IVC

Issues/comments:• The internal screens (still, HEX, MC) must be installed in clean

conditions, so they will not be installed in this phase through the floor opening. They will be installed and removed from the clean room at the end of the dry fit

• All the screens/vessels are delivered in upright position on a basement

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Initial installation 1.2: 4K (40K, 300K) vessel set on platform

Option1 Option2

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Initial installation 1.2: 4K (40K, 300K) vessel ready for lifting

Lifting ears and eye bolts are installed and hoist cables connected

Lifting cables

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Initial installation 1.2: 4K (40K, 300K) vessel lifted and fixed to the 4K flange

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Initial installation 1.2: testing

• Leak tightness• Vacuum• Deformations

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1 Initial installation1.3 Installation of STILL-HEX-MC plates

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Initial installation 1.3: installation of temporary support structure

The main platform is moved aside

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Initial installation 1.3: 300K-40K-4K vessels lowered down

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Initial installation 1.3: the floor is closed and sealed off

From this moment on the area around the cryostat will have to be kept clean at all time

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Initial installation 1.3: installation of the STILL plate

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Initial installation 1.3: installation of the STILL plate

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Initial installation 1.3: installation of the HEX and MC plates

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Initial installation 1.3: installation of the HEX and MC plates

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• 2.1 integration of all the internal components (DU, pulse tubes, wire inserts, source guiding tubes, suspensions)

– Preliminary cooling tests and functional tests of all components• 2.2 installation of STILL lateral lead shield• 2.3 installation of the internal top lead shield and dummy detector (DD)

– alignment and calibration of the detector suspension system • 2.4 Final tests

• COMMENTS:– The 2.1 phase will last for quite some time and will require several openings and

closings of the cryostat: it is recommended to use a temporary support structure on the main platform to store the screens/vessels. This would allow the assembly of the main external shielding in parallel and off-line

– In phase 2.1 not all the screens/vessels may be needed for the tests: those internal are stored on the first floor and could be installed when needed independently from the external ones

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2.1 integration of all the internal components (DU, pulse tubes, wire inserts, source guiding

tubes, suspensions)

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Cryostat commissioning 2.1: installation of internal components

In parallel: assembly of main

shielding

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Cryostat commissioning 2.1: installation of internal screens (1)

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Screens lifted by the cable hoist system or by hydraulic

jacks

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Cryostat commissioning 2.1: installation of external vessels (1)

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Cryostat commissioning 2.1: installation of external vessels (2)

main shielding

completed

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Cryostat commissioning 2.1: cold tests

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During testing:• The temporary support is removed

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During testing:• The platform with the main

shielding is brought on-axis

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2.2 installation of STILL lateral lead shield

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Cryostat commissioning 2.2: preparation for installation of STILL lateral lead shield (1)

The floor is opened

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The 4K-40K-300K vessels are lowered into the main shield

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• Floor closed• External vessels sealed off

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Removal of internal screens

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Removal of internal screens

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Main shielding moved aside

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Temporary support added on main platform

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Platform raised and sealed

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• Floor opened• Temporary support raised

to reach floor level

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Cryostat commissioning 2.2: installation of STILL lateral lead shield (1)

Still lead cradle set on support

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Platform lowered


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Bottom lead layer and first ring added

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Platform lowered

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Installation of 2° lead ring

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Platform lowered

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Lead rings installation completed

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• Top Cu ring added• Lead assembly lifted• Tie rods connected• Load transfer to STILL plate• Check correct placement

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Cryostat commissioning 2.2: preparation for installation of internal top lead shield (1)

• Platform lowered• Floor closed• Temporary support removed

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• Main shielding moved on axis• Flexible seal is connected• Floor opened


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• The main shielding is raised• The still lateral lead shield

assembly is transferred on the main shielding


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• The platform is lowered• The floor is closed


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• The internal screen (STILL; HEX; MC) are installed by using the hoist system


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• The internal screens (STILL; HEX; MC) are installed by using the hoist system


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• The floor is opened• The internal screens (STILL;

HEX; MC) are lowered into the main shielding by using the hoist system


This is the final configuration

of the cryostat vessels/screens in “fully open”

conditions

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2.3 installation of the STILL internal top lead shield and dummy detector (DD)

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• The floor is closed• The floor plug must be

designed to withstand the load of the internal top lead shield

Cryostat commissioning 2.3: installation of internal top lead shield (1)

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A support structure allowing access to the anchoring points at the bottom of the support plate is added


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The base support plate is set on the platform


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The Lead layers and copper sheets are added in sequence


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• The platform is raised to bring the internal top lead shield assy at the nominal position

• The suspensions are connected• The load is transferred from the

platform to the suspensions


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• The platform is lowered• The position of the internal top

lead assy is surveyed and adjusted as required


An alternative option may consist in using the detector installation cart, thus avoiding moving up and down the main platform

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• The dummy detector is set on the platform

• the same cart+rail system used later on to install the detector may be used

Cryostat commissioning 2.3: installation of the dummy detector (1)

Installationcart

Rail system

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• The dummy detector (DD) is lifted up to the nominal position

• Load is transferred to the suspensions

• The position of the DD is checked and the suspensions are adjusted if needed

Cryostat commissioning 2.3: installation of the dummy detector (1)

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• The top part of the MC screen is installed by hands

• The innermost sections of the source guiding tubes are added

Cryostat commissioning 2.3: installation of the top part of MC screen

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Cryostat commissioning 2.3: installation of the STILL top lead ring

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• The floor is opened• The platform is raised up to

approach the MC flange• The MC screen is fastened

Cryostat commissioning 2.3: closing of the cryostat (1)

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The platform is raised up again to allow the fastening of the HEX and STILL screens and of the STILL lateral lead shield


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The 4K-40K-300K vessels are lifted with the cable hoist system


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2. Cryostat commissioning 2.4 Final tests

The cryostat is cooled down and the final commissioning tests are carried out

including the full test of the calibration system

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3. Detector installation

3.1 Preparation for the installation (removal of dummy detector)

3.2 detector installation

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The 300K-40K-4K vessels are lowered with the cable hoist system

Preparation for detector installation 3.1: opening of the cryostat (1)

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The STILL-HEX-MC screens and lead shield are lowered by lowering the platform


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• The platform is fully lowered• The floor is closed


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The detector installation cart+rail system is installed on the floor

Preparation for detector installation 3.1 : removal of the dummy detector (1)

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The dummy detector is lowered


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• The dummy detector is removed

• The clean room around the cryostat is now switched to “radon-free”


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The detector is moved in

Detector installation 3.2 (1)

Radon-free

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• The detector is raised to the nominal position

• The load is transferred to the suspensions

Radon-free


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• The suspensions are adjusted if needed

• The tapes are connected to PP1• The source guiding tubes are

adjusted to match

Radon-free


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• The floor is opened• The platform is raised• The MC-HEX-STILL screen and the

STILL lead shield are fastened to the corresponding plates

• The detector is flushed with N2

Radon-free


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• The 4K-40K-300K vessels are raised by the cable hoist system

• The main shield is raised up to the top position

The experiment is ready to run


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4. maintenance

Subset of the procedures followed for the detector installation

cryostat assembly, integration and commissioning procedures

Documents

auxiliary platform

basementinitial installation

kinitial installation

sequence initial installation

platform addon

plates ready

floor levelthe main

stack of plates