CERN
LHC Project Document No.
CH-1211 Geneva 23
Switzerland
LHC-VC8-TP-0001
CERN Div./Group or Supplier/Contractor Document No.
AT-VAC
the
EDMS Document No.
Large
Hadron
Collider
842128
project
Date: 2007-05-10
Procedure
COMMISSIONING OF THE LHCB BEAMPIPE
EXPERIMENTAL SECTOR IP8.X
Abstract
This document describes the procedure to be followed for the first commissioning of the
experimental sector of the LHCb beampipe VACSEC.IP8.X, as planned to be performed
in May and June 2007. It takes into account the status of the installation at the moment
of the commissioning.
Prepared by :
Délio Ramos
AT/VAC
Delio.Ramos@cern.ch
Checked by :
LHC Project Document No.
LHC-VC8-TP-0001
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History of Changes
Rev. No.
Date
Pages
Description of Changes
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Table of Contents
1.
INTRODUCTION .......................................................................................4
2.
LIST OF DOCUMENTS ...............................................................................4
3.
3.1
3.2
PROCEDURE.............................................................................................5
PREPARATION PHASE ............................................................................... 5
NEG ACTIVATION PHASE .......................................................................... 6
4.
REFERENCES............................................................................................8
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1. INTRODUCTION
The commissioning of the LHCb beampipe VACSEC.IP8.X is planned for May and June
2007. This corresponds to the pump-down, leak detection, instrumentation testing,
surface conditioning and pure neon injection, leaving the beam vacuum chamber
between VVGSF.33.1L8.X and VVGST.198.1R8.X with NEG activated surfaces,
therefore only requiring the neon pump-down to be ready for beam.
Although the LHCb beampipe is composed of all vacuum equipment in-between Q1
magnets, the installation of sectors VACSEC.A1L8.X and VACSEC.A1R8.X is not
complete. However, the most important sector traversing the LHCb detector
(VACSEC.IP8.X) is ready for commissioning, which must be done as soon as possible
in order to avoid conflict resources with the remaining experimental beampipes, as
well as with the detectors installation.
As the VAX assemblies are not installed, an RGA and a penning gauge will be
temporarily mounted, to allow the pressure reading at the downstream end of the
beampipe. These will be replaced by blank flanges and mounted on the VAX assembly
after this commissioning.
The remaining sectors will be commissioned later with mobile pumping groups.
The purpose of the pure neon injection is to allow the venting of the beampipe to
atmospheric pressure while preventing the saturation of the NEG coating. However,
the leaks on the VELO RF-boxes of the order of 2.6x10-5 mbar, measured with 1.5
mbar differential pressure of helium, will allow diffusion of air into the beampipe when
the VELO detector volume will be open to air for the detectors installation. This may
imply another bakeout after detector installation [1] .
Scaffolding and handling are provided by LHCb.
2. LIST OF DOCUMENTS
The following list of documents form an integral part of this procedure:
Description
Location
2.A
Planning for the LHCb beampipe commissioning
- Sector IP8.X
EDMS Id: 837026
2.B
Instrumentation layout of the LHCb beam
vacuum system – temporary configuration for
the first commissioning of the VACSEC.IP8.X
EDMS Id: 842124
2.C
Instrumentation layout of the LHCb beam
vacuum system
EDMS Id: 842125
2.D
Layout of the bakeout heaters and control
channel programs for the first commissioning of
LHCb beampipe VACSEC.IP8.X
EDMS Id: 842122
2.E
Services in the LHCb cavern for the LHCb
beampipe commissioning
EDMS Id: 842120
2.F
LSS Vacuum layouts
LHC Functional Database
2.G
Procedure for the air pumpdown of the LHC
experimental beam vacuum chambers
EDMS Id: 842115
2.F
LHCb beampipe drawings
CDD drawing numbers at:
http://cern.ch/delio.ramos/LHCb.htm
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3. PROCEDURE
3.1 PREPARATION PHASE
Status before start: Beampipe vented with N2. Sector valves VVGSF.33.1L8.X and
VVGST.198.1R8.X closed. The 3 volumes separated by the sector valves were vented
independently, eventually they are not at the same pressure. Hence, before operating
the sector valves, the pressures must be equilibrated.
1
Step description
Ref.
doc.
Equipment
required
Open the volume on the downstream side of
VVGST.198.1R8.X to air and install temporarily the penning
VGPB.219.1R8.X and RGA VGAB.219.1R8.X on the bellows
module VMABJ. The RGA is assembled on a CF63 elbow.
2.B
-CF63 elbow
-VGPB
-VGAB
-CF63 blank
flange with VAT
CF16 or HOKE
valve
Install a CF63 blank flange with VAT CF16 or HOKE valve on
the downstream side of MBXWS magnet (VVFMB.214.1R8.X).
2
Connect the gauges and ion pump cables.
2.B
3
Using the VELO vacuum system, pump 50 mbar and then
inject N2 to equilibrate the pressure in the VACSEC.IP8.X to
atmosphere.
2.B
-NEG sample
-Tube with
CF40 flange
Mount the NEG sample on the VC8G beampipe.
-VGAB
Mount RGA (VGAB) on the VELO.
-Transition for
VELO RGA
Open VVFMB.214.1R8.X to expose the volume to
atmosphere.
Open the sector valve VVGST.198.1R8.X.
Close VVFMB.214.1R8.X.
Open VVFMB.72.1L8.X to expose the volume to atmosphere.
Open the sector valve VVGSF.33.1L8.X.
Close VVFMB.72.1L8.X
4
Pump-down the beampipe with both sector valves open.
While pumping, regulate the restriction valve MV305 on the
detector vacuum pumping line. Test instrumentation.
2.B
5
Leak detection of previously installed equipment, with the
leak detector connected to the VELO.
-Leak detector
6
Close VVGST.198.1R8.X.
-Leak detector
Vent the MBXWS volume trough VVFMB.214.1R8.X and inject
He inside to leak check the sector valve seat.
Close VVFMB.214.1R8.X.
7
Vent the VACSEC.IP8.X with Ne using the injection table and
line.
While injecting, regulate the restriction valve MV304 on the
2.B
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detector vacuum venting line.
8
Open VVFMB.214.1R8.X to expose the volume to
atmosphere.
2.B
Open VVGST.198.1R8.X.
9
Preparation phase finished. Status:
VVFMB.72.1L8.X closed
VVGSF.33.1L8.X closed
VVGST.198.1R8.X open
VVFMB.214.1R8.X closed
3.2 NEG ACTIVATION PHASE
Step description
Ref.
doc.
Equipment
1
Cabling of bakeout racks for the gas injection table and line.
2.D
Bakeout racks E
and B (24
channels each)
2
Programming and testing of bakeout racks for the gas
injection table and line.
2.D
3
Commissioning/NEG activation of the injection table and
injection line.
Doc?
4
Assembly of bakeout equipment onto the beampipe and
VELO.
2.D
All bakeout equipment provided by AT-VAC except
the VELO vacuum vessel walls which have a
permanent heating and a dedicated controller
integrated in the VELO mobile control rack.
However, the VELO flanges were not accounted by
NIKHEF, they will be heated using AT-VAC’s collars
and power control channels.
RICH1 side panels are open and mirrors removed to
provide access to the beampipe. Removable
jackets.
TT, OT and IT, are open. “Free” access to the
beampipe from the RICH1 exit window up to RICH2.
Platform to reach the beampipe level needed in the
OT/IT region. Removable jackets.
RICH2 cannot be opened. A removable jacket is
inserted from the OT/IT side. A temperature sensor
on the detector wall, to be installed by RICH2, will
provide an interlock with the power controler.
Power is cut-off if the RICH2 temperature reaches
70ºC [2] . RICH2 provides the cable and connector
up to the power controler. To prevent the detector
overheating, compressed air is injected between the
beampipe and the RICH2 tube to extract the
dissipated power by convection. Compressed air line
provided by LHCb, injector and flow meter provided
Bakeout jackets,
heating tapes,
insulating
blankets,
heating collars.
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by AT-VAC.
M1, SPD/PS, ECAL and HCAL open. Scaffolding to
reach the beampipe level. Removable jackets.
MF does not open. Permanent heating system with
band heaters and Microtherm insulation. 1
thermocouple + 1 redundancy per heating circuit.
Connectors at the beampipe level on both upstream
and downstream sides. Temporary cables needed to
reach the controlers in the cavern floor and the
RB86 tunel.
All flanges in the beam volume are actively heated.
5
Cabling of bakeout racks for the beampipe and VELO.
2.D
Bakeout racks A,
B and D (24
channels each)
Bakeout Rack C
(8 channels)
6
Programming and testing of bakeout racks for the beampipe
and VELO.
2.D
Maximum temperatures:
• VELO vessel and aluminium window – 150ºC
max (Helicoflex seal manufacturer specifies
maximum 120ºC)
• Beryllium – 220ºC (max 250ºC)
• Aluminium flanges – 220ºC (max 230ºC)
• Aluminium bellows – 200ºC max
• Bimetallic transition flange stainless
steel/aluminium – 220ºC (230ºC max)
• Stainless steel, tubes, bellows, flanges –
220ºC (max. 300ºC)
• The remaining copper chambers, valves,
instrumentation, modules, pumps, etc.
Following “standard LSS” parameters.
7
Install dial gages on the beampipe flanges and supports to
measure the displacements due to pressure and
temperature.
8
Pump-down the beampipe through the VELO vacuum
system.
2.G
9
Close VVGSF.33.1L8.X
2.B
10
Bakeout and NEG activation
2.D
Doc?
11
Ne injection
Doc?
12
Close VVGST.198.1R8.X
2.B
13
Activation phase finished. Status:
2.B
VVFMB.72.1L8.X closed
VVGSF.33.1L8.X closed
VVGST.198.8.X closed
VVFMB.214.1R8.X closed
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VACSEC.IP8.X at atmospheric pressure of Ne, balancing to
atmosphere
VELO detector volume at atmospheric pressure of Ne, all
valves closed.
Volume upstream of VVSGF.33.1L8.X under vacuum.
Volume downstream of VVGST.198.1R8.X at atmospheric
pressure of Ne
Ne injection line and injection table at 1000 mbar of Ne,
ready to inject, if necessary to equilibrate pressure
difference between the beampipe and atmosphere.
14
Demount temporary bakeout equipment
4. REFERENCES
[1]
Minutes of meeting on “LHCb Rescue commissioning procedure accounting for
the leaks in the VELO rf-boxes”, 14-Mar-2007.
[2]
D. Ramos, H. Kos, “Test to determine the temperature of the RICH2
detector tube during bakeout of the LHCb beampipe”, May 2007, EDMS Id:
841120