www.cells.eswww.cells.es

Marta Llonch1, Fabien Rey2, Jon Ladrera1

1 CELLS�ALBA, 08290 Cerdanyola del Vallès, Spain2 European Spallation Source ESS AB, S�221 00 Lund, Sweden

Constructive solution

Slab evolution and status at ALBA Synchrotron

The 3GeV ALBA synchrotron light facility has currently seven operationalstate�of�the�art phase�I beamlines, comprising soft and hard X�rays.Additionally, two phase�II beamlines are in construction. Since as earlyas 2012, ALBA Synchrotron has been hosting official users; however, themachine independent slab is being surveyed since 2009 (once the wholeinstallation was finished). The ALBA critical floor slab has an outerradius of 60m and supports the Tunnel, the experimental lines and theservice area as well.To achieve the expected accuracy in the subsequent alignment works isessential to have an updated accurate survey reference networkinstalled in the critical slab. An important goal is to be able to track themovement of the slab and consider the components position. In thisposter, we present you a report with general information about our slabconstructive method, our survey network and an historical evolutionreport of the ALBA reference network from the very beginning.

Abstract

Our survey network has an amount of 564 alignment references,approximately. All the alignment points are placed in the ground and walls,along the whole slab. This tool enables us , in one hand, to align and installthe Machine and beamlines components, in the other hand to track themovements and evolution of the slab and consider the componentsrealignment.

According to the geotechnical studies, the site iscomposed by a clayey soil with low plasticity,which ensures stability against small movementsand traffic. However a proper design of thecritical slab is needed. The taken solution for thecritical slab floor area was 1 m of reinforcedconcrete slab resting on a base of 2 m thickness

WATER TREATMENT

INDEPENDENT SLAB

AUXILIARY BUILDING

LABORATORIES

OFFICES

PARKING

TECHNICAL

BUILDING

BUNKER

WORKSHOP

External radius 60 m

Internal radius 36.5 m

Total surface 7200 m2

Max. Floor differential displacements ˂ 2.5 mm/year

Network

composed of a gravel filling that was properly compacted and protected bytwo 15 cm poor concrete layers. The whole slab is divided in 16 sectors(about 450 m2 each one).

Network evolution Current statusThe slab differential displacements from the beginninghave been almost always within the required parameters.The last April campaign demonstrates the same. Duringthe last two years 2012�2014, the maximum displacementshave been near 3 mm in vertical direction in sector15. Thiscan come from irregular water cycles or the proximity of acellar in the area. The sector 15 area is where mostmovements have been recorded during all campaigns.

Statistic dX dY dZ Mag

Min -0.86 -0.66 -1.80 0.14

Max 0.66 0.69 3.27 3.29

Average -0.00 0.00 0.31 0.98

RMS 0.35 0.30 1.03 1.13

Statistic dX dY dZ Mag

Min -0.48 -0.26 -3.33 0.06

Max 0.36 0.32 1.49 3.34

Average -0.02 0.05 -0.23 0.62

RMS 0.19 0.12 0.78 0.81

2012

-20

1420

09 -

2010

2010

-20

12

EF 160EF 203

EF 316EF 94

Statistic dX dY dZ Mag

Min -0.93 -0.62 -3.05 0.26

Max 1.14 0.84 3.70 3.71

Average -0.06 -0.06 -0.32 1.61

RMS 0.35 0.23 1.70 1.76

Front wall – EF 304 0.982.07

End station – EF 160 3.06

Distance between points 22572

2014

2012ΔZ

160 EF

304 EFΔZ

BOREAS End Station

BOREAS Front Wall BOREAS area slabtilting during the lasttwo years.

Slab tilting = 0.09 mrad*

EF 304EF 160

* Value corresponding to the slab tilting from July 2012 to April 2014

Extreme slab points height evolution.

2009 2010 2011 2012 2013 2014

EF160 0 0.24 2.00 3.77 5.30 6.83

EF316 0 -2.65 -2.93 -3.21 -2.65 -2.09

EF94 0 -0.72 -1.31 -1.90 -1.54 -1.17

EF203 0 -0.83 -0.54 -0.25 0.10 0.45

-4-202468

∆Z

Coo

rdin

ate

mm

SLAB REFERENCE POINTS RELATIVE EVOLUTION THROUGH YARS