lhec detector installation preliminary study€¦ · the following is a very preliminary study of...

LHeC Detector Installation Preliminary Study

LHeC Workshop, January 20-21, 2014

Andrea Gaddi / CERN

LHeC Workshop, January 20-21 2014. A. Gaddi

LHeC Detector Installation

Talk content.

1) Introduction. 2) Detector assembly on surface. 3) Detector lowering & integration underground. 4) Maintenance & opening scenario. 5) Timelines.

LHC P2 LHeC



Introduction.

The following is a very preliminary study of the detector assembly and integration at CERN LHC P2, with some considerations on the detector maintenance scenario. The usual constrains that apply to the detector integration study, are made here even tighter due to the fact that the detector has to replace an existing one, in the shortest allowable time given by the machine shutdown. Considerations on the activation of the present ALICE detector at LHC P2, at > 300 fb-1 LHC integrated luminosity and consequences on how fast and safely it can be dismantled are not presented here for lack of time. They shall be addressed in the next future.



LHeC Detector assembly on surface.

The strategy proposed is to complete as much as possible the assembly of the detector on surface, where the detector construction can proceed without impact on the LHC physics runs. The detector has been split in the following main parts (14): 1) Coil cryostat, including the superconducting coil, the two integrated dipoles and

eventually the EMCal, if the L-Ar version is retained (1). 2) Five HCal tile calorimeter modules, fully instrumented and cabled (5). 3) Two HCal inserts, forward and backward (2). 4) Two EMCal inserts, forward and backward (2). 5) Tracking system, Vertex detector & Beam-pipe (3). 6) Space-frame for the Muon detector, outside the HCal tile calorimeter (1).



LHeC Detector baseline design.

HCal modules (5)

Bwd HCal plug

Fwd HCal plug

Bwd EMCal plug

Fwd EMCal plug

EMCal barrel

Tracker & Vertex

Cryostat



P2 facilities on surface. Crane capacity on surface b.SX2: 65tons.



Heavy detector elements lowering. The maximum weight of a single element to be lowered from surface to underground has been limited to 300 tons, in order to make possible the lowering by renting a standard crane, as already applied by L3 for its barrel HCal.



Heavy detector elements lowering.

mobile crane

65t bridge crane



Detector elements lowering (Alice space-frame example).



Coil tests on surface.

The superconducting coil and the two integrated dipoles can be tested at nominal current on surface, whilst the field mapping shall be performed underground, once the cryostat inserted into the L3 Yoke, without the inner detector components (HCal plugs, Tracker & Vertex). The electrical tests on surface will include: •  Progressive powering ramps to nominal current.

•  Progressive discharge ramps (fast & slow).

•  Measurement of the operating temperature and current margins.



Underground facilities.

Crane bridge 2x20tons PX24 – 15x15m2

LHC tunnel LHC tunnel



Detector integration in the L3 magnet. The detector, including the Muon chambers, fits inside the former L3 Magnet Yoke. The aim, to prevent losing time in dismantling the L3 magnet, is to make use of the sturdy L3 Magnet structure to hold the detector central part on a platform supported by the L3 Magnet crown, whilst the Muon chambers will be inserted into lightweight structures attached to the inner part of the barrel and the doors. The existing door openings are large enough to house the external part of the final dipoles and provide access for cables and services.

Alice parts to be dismantled L3 magnet to be re-used



Detector lowering & integration underground. L3 Yoke

LHeC Muon barrel

L3 Coil

LHeC Muon endcap



Maintenance & opening scenario.

A minimum maintenance scenario has been analysed. This foresees the possibility of opening the detector to get access to the Central Tracker & the Vertex. To allow this, the two heavy HCal inserts have to be removed from inside the cryostat and moved along z on the platform that supports the last machine elements. These elements have to be previously disconnected from the beam-pipe and moved away on the same platform along x. To avoid disconnecting the HCal inserts form the main services, cable-chains will accomodate extra-lengths of cables, fibres and pipes.



LHeC inside the L3 Magnet, longitudinal cross-section.

HCal

EMCal+TK+VTX

Cryostat

Muon chambers

L3 Magnet Yoke

Platform for machine elements & HCal inserts removal



LHeC inside the L3 Magnet, transversal cross-section.

To be noted: the LHeC interaction point has an offset of 300mm along Y and 870mm along Z, with respect to the centre of the L3 Magnet Yoke.

L3 Magnet

Muon chambers

HCal

X

Y



Timelines. The assembly on surface of the main detector elements, as previously defined, can start at any time, providing that the surface facilities are available, without sensible impact on the LHC run. The Coil system commissioning on site (T=0) could request three months, preparation for lowering one month and lowering one week per piece (14 pieces in total). In the same time (7 months, tbv – the delay depends on the level of activation and the procedure adopted for dismantling Alice detector) the L3 Magnet will be freed up and prepared for the new detector. Underground completion of the integration of the main detector elements inside the L3 Magnet would require about two months, cabling and connection to services some six months, in parallel with the installation of the Muon chambers, the Tracker and the EMCal. The total estimated time, from the starting of the commissioning of the Coil system on surface to the commissioning of the detector underground is thus 15 months. The field map would take one extra month. The beam-pipe bake out & vacuum pumping could take another month. Some contingency is foreseen between the lowering period (14 weeks) and the integration inside the L3 Magnet of the same elements (2 months).



Conclusions.

This preliminary study shows that the LHeC Detector fits inside the former L3 Magnet. This would avoid the dismantling of the heavy iron structure that could be re-used as a stiff support for the new detector. The layout is also compatible with a minimum maintenance scenario, allowing access to the LHeC inner detectors in a relatively short time (although the last machine elements have to be disconnected form the beam-pipe and displaced aside a few meters). The schedule for detector installation & commissioning could finally meet the LS3 plans, or, under some provisions, even the shorter LS4, providing that most of the assembly is done on surface and Alice detector can be quickly (i.e. < 7 months) dismantled.



Back-up slides.

lhec detector installation preliminary study€¦ · the following is a very preliminary study of...

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