75 research outputs found
Finite elements analysis of the CMS feet
No full textThe aim of this analysis is to cross-check the mechanical behavior of the CMS support feet with the F.E. program ANSYS 5.4. A previous analysis has been carried out with CASTEM 2000 by Hubert Gerwig, determining the actual design. The operating conditions are the normal position with the detector closed and the moving position, while the rings of the detector are opened. For these scenarios, the deformations and stresses have been calculated. The results obtained show that the displacements and deformations are negligible and the stresses are within the safety limits. An additional 15% lateral acceleration and 15% vertical acceleration have also been taken into account, to check if the feet withstand an earthquake
The CERN CMS Barrel Design team: J. Andre, M.-H. Bovard, G. Duthion, J.-P.Girod, J.-P. Grillet, P. Petiot, L. Veillet, T. de Visser, G. Waurick, H. Gerwig, A. Herve.
No full textAfter 7 years of design, calculation and hard work the first barrel ring of CMS stands free in the surface hall of P5. 1200 tonnes of steel nearly 17m high and 15m in diamter. The width is 2.5 meter. The Ferris Wheel served as a jig to build up the 3-layered ring. At the end of the assembly the ring is separated from the jig by rotating the special corner pieces and then move the whole mass on air pads
Final dimensional test with alu-jig travelling through the CMS Inner vacuum tank
No full textThe inner vacuum tank is an object of 13m lenght and 6m diameter that is completely made of stainless steel SS304. To allow insertion of the inner detectors, especially the hadronic calorimeter, a rail at 9 and 3 o'clock position is integral part of the cylindrical tank. To insert, weld and finally machine this rail was a big challenge for the manufacturer. The dummy jig presented on the pictures represents the diameter of the most outer corner of the hadronic calorimeter plus a scintillator and some cables
Machining of inner vacuum tank rails
No full textThe length of the vactank, 12.8meter doesn't make it easy to get this rail machined on its total length
The outer vactank, an object of 7.6m diameter and 13m length is built up of three cylindrical parts. The central part that is integral part of the central barrel and the the extension on either side each one 4.5m long. These extensions house the shoulders that will support and prestress the CMS Coil. To weld the extensions onto the central part a full penetration weld of 24m length and 45 mm thickness has to be done by hand from inside and outside the vacuum tank and its deformation is controled permanently.
No full textThe outer vacuum tank will hold the coil suspension system and transmits the weight of the inner detectors to the central barrel. Its thickness is staggered. In the central part its thickness is 60 mm and then goes down to 30 mm at the extremity
Final stage of inner vactank machining
No full textMesures des positions des bossages qui connecteront vers la plateforme rotative, fabricated actually chez HANJUNG company in Changwon, South Kore
October, 25th, 2000 First Barrel Ring with extension shaft ready for separation
No full textThe Ferris Wheel has served as a tool to build up the three-layered Barrel of the CMS return yoke. Now at the end of the assembly the barrel ring will be put on air pads and be pushed out
Visit at PFAFF Silberblau for follow -up of mechanical jacks fabrication for HF
No full textThe HF detctor is sitting on either side of the CMS experiment at a height of the beam, 8.79m This detector weighs 220 tons will be lifted in 4 steps on its working position. 4 mechanical jacks with 100t force each will act on each corner of rectangle of 5600mm x 3200mm. The individual main pieces of the jacks are shown here. Next step is the assembly of the jacks by putting together housing, groundplate, spindle, gear, worm gear etc. Delivery of the first 4 jacks in dec.200
The CMS solenoid goes down to 100 Kelvin (-170 degrees Celsius)
No full textAfter successful closing of the vacuum vessel and achievement of a good vacuum the cool-down of the CMS coil started in early February. The temperature of the coil, as of Friday February 17th, is about 100 Kelvin (-170 degrees Celsius). Members of the CERN CMI group and of Saclay stand in the vacuum vessel (from left to right): Hubert Gerwig, Francois Kircher, Benoit Cure, Domenico Campi, Bruno Levesy, Andrea Gadd
Engineering challenges in mechanics and electronics in the world’s first particle-flow calorimeter at a hadron collider: The CMS high-granularity calorimeter
No full textThe CMS Collaboration is preparing to build replacement endcap calorimeters for the HL-LHC era. The new high-granularity calorimeter (HGCAL) is, as the name implies, a highly-granular sampling calorimeter with 47 layers of absorbers (mainly lead and steel) interspersed with active elements: silicon sensors in the highest-radiation regions, and scintillator tiles equipped with on-tile SiPMs in regions of lower radiation. The active layers include copper cooling plates embedded with thin pipes carrying biphase CO2 as coolant, front-end electronics and electrical/optical services. The scale and density of the calorimeter poses many engineering challenges that we discuss here. These include: the design and production of 600 tonnes of stainless-steel absorber plates to very high physical tolerances; the development of the CO2 cooling system to maintain each 220-tonne endcap at −35 °C whilst the electronics dissipate up to 125 kW; the need to cantilever the calorimeters from the existing CMS endcap disks, using titanium wedges; the production of a thin but strong inner cylinder to take the full weight but have little impact on physics performance; the development of low-power high-dynamic-range front-end electronics for over 6 million detector channels; the integration of all services in a restricted volume with only a couple of mm height. We give an overview of the design of HGCAL, focusing on the materials and techniques being used to overcome the many challenges for this world’s first calorimeter of its type at a hadron collider
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