bgv installation

BGV installation

Paolo Magagnin

Girders’ installation

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BGV girder Upstream girder

Chambers’ installation

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BGV assembly lift by a crane over the beam pipe

Chambers’ installation

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Precautions during installation:1. Small distance between flanges DN235 and Beampipe 1 (7 mm)

Solution: - Use safety bars, to ensure to keep the right distance during the approaching stage.- adjust the positioning screws on the left outwards, and ones on the right 15 mm inside.

Chambers’ installation

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Precautions during installation:2.A With the lateral support mounted, the assembly have the barycentre outside the two feet:

Solution:- right after the adjustment on the table, and before unhook the chamber from the crane, tight the 2 blue washers and do not remove them anymore.

Chambers’ installation

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Precautions during installation:2.B The blue right washer has a functional vertical gap.

With the lateral support mounted, the right foot is hold down by the washer

by removing the lateral support, the foot is held down by the gravity, and the chamber moves due to the functional gap (few tens of mm). This involves, the loose of alignment precision and stresses in the window.

Solution:- Add a sheet between the washer and the feet

(dangerous if forgotten)- - Clamp the feet to the table by external clamps. If

uncomfortable for the alignment, it might be added a 15 kg weight at the J.I.V.C. extremity, to overcame the clamps during the alignment.

Chambers’ installation

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Precautions during installation:

3. Reduced distance between the chamber protection and the internal beam pipe: 70 mm.

Solution:Feasible to remove the protection without deforming it. Attention should be paid to do not touch the chamber.

BGV protection

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After the bake out it can be mounted again the lateral support to protect the chamber before and during the first part of the detector support structure’s mounting, adding to the 52 mm tube the same protection used for the bake out.

Detector mounting

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3. Reduced distance between the chamber’s support and the detector’s support structure: 70 mm, while they are needed 170 mm to remove the support.

Detector mounting

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Protection for structure’s mounting.

Detector mounting

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Sliding protection for detector mounting, in order to bring the detectors as close as possible to the chamber (10 mm), while keeping the protection.

Detector mounting

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Detector installation and first regulation by normal crews, done with the protection.

Detector positioning

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Precise positioning of the detectors by measuring their distance from the vacuum chamber with feeler gauges, and sliding the detectors by means of micrometric stages.