engLebrun, PIndustrial Technology for Unprecented Energy and Luminosity: The Large Hadron ColliderAccelerators and Storage RingsLHC-Project-Report-745CERN-LHC-Project-Report-745With over 3 billion Swiss francs procurement contracts under execution in industry and the installation of major technical systems in its first 3.3 km sector, the Large Hadron Collider (LHC) construction is now in full swing at CERN, the European Organization for Nuclear Research. The LHC is not only the most challenging particle accelerator, it is also the largest global project ever for a scientific instrument based on advanced technology. Starting from accelerator performance requirements, we recall how these can be met by an appropriate combination of technologies, such as high-field superconducting magnets, superfluid helium cryogenics, power electronics, with particular emphasis on developments required to meet demanding specifications, and industrialization issues which had to be solved for achieving series production of precision components under tight quality assurance and within limited resources. This provides the opportunity for reviewing the production status of the main systems and the progress of the project.2004http://cds.cern.ch/record/788536http://cds.cern.ch/record/788536oai:cds.cern.ch:788536 engBaglin, VDupont, HGarcin, TVacuum Characterization of a Woven Carbon Fiber Cryosorber in Presence of $H_2$Accelerators and Storage RingsLHC-Project-Report-744CERN-LHC-Project-Report-744Some of the cold bores of the Large Hadron Collider (LHC) will operate at 4.5K. In these elements, the desorbed H2 pressure will rapidly reach the saturated vapour pressure, 3 orders of magnitude larger than the design pressure. Therefore, the use of cryosorbers is mandatory to provide the required pumping capacity and pumping speed. The behaviour of a woven carbon fiber to be potentially used as a cryosorber has been studied under H2 injection. The pumping speed and capacity measured in the range 6 to 30 K are described. Observations made with an electron microscope are shown. A proposed pumping mechanism and the implications for the LHC are discussed.2004http://cds.cern.ch/record/788535http://cds.cern.ch/record/788535oai:cds.cern.ch:788535 engKnaster, J RJenninger, BRamos, DRatcliffe, GVeness, R J MThe Design of Cold to Warm Transitions of the LHCAccelerators and Storage RingsLHC-Project-Report-743CERN-LHC-Project-Report-743The Large Hadron Collider (LHC), the next accelerator being constructed on the CERN site, will accelerate and collide 7 TeV protons and heavier ions up to lead. More than 1700 cryomagnets working at 1.9 or 4.5 k will form part of the magnetic lattice of the LHC. The beam pipe passage from cryogenic temperatures to room temperature zones will be achieved by 200 cold to warm transitions (CWTs). The CWTs will compensate for longitudinal and transversal displacements between beam screens and cold bores, ensuring vacuum continuity without limiting the aperture for the beam. The transverse impedance contribution is kept below the assigned total budget of 1 MO/m by means of a 4 µm thick Cu coating that also minimises the dynamic heat load through image currents. Tests have been performed that confirm that the static heat load per CWT to the cryomagnets remains below 2.5 W, hence validating the design.2004http://cds.cern.ch/record/788534http://cds.cern.ch/record/788534oai:cds.cern.ch:788534 engBaglin, VJenninger, BGas Condensates onto a LHC Type Cryogenic Vacuum System Subjected to Electron CloudAccelerators and Storage RingsLHC-Project-Report-742CERN-LHC-Project-Report-742In the Large Hadron Collider (LHC), the gas desorbed via photon stimulated molecular desorption or electron stimulated molecular desorption will be physisorbed onto the beam screen held between 5 and 20 K. Studies of the effects of the electron cloud onto a LHC type cryogenic vacuum chamber have been done with the cold bore experiment (COLDEX) installed in the CERN Super Proton Synchrotron (SPS). Experiments performed with gas condensates such as H2, H2O, CO and CO2 are described. Implications for the LHC design and operation are discussed.2004http://cds.cern.ch/record/788533http://cds.cern.ch/record/788533oai:cds.cern.ch:788533 engMahner, EdgarEfthymiopoulos, IliasHansen, JanPage, EricVincke, Helmut HBeam-Loss Induced Pressure Rise of LHC Collimator Materials Irradiated with 158 GeV/u $In^{49+}$ Ions at the CERN SPSAccelerators and Storage RingsLHC-Project-Report-741CERN-LHC-Project-Report-798During heavy ion operation, large pressure rises, up to a few orders of magnitude, were observed at CERN, GSI, and BNL. The dynamic pressure rises were triggered by lost beam ions that impacted onto the vacuum chamber walls and desorbed about 1044 to 107 molecules per ion. The deterioration of the dynamic vacuum conditions can enhance charge-exchange beam losses and can lead to beam instabilities or even to beam abortion triggered by vacuum interlocks. Consequently, a dedicated measure-ment of heavy-ion induced molecular desorption in the GeV/u energy range is important for LHC ion operation. In 2003, a desorption experiment was installed at the SPS to measure the beam-loss induced pressure rise of potential LHC collimator materials. Samples of bare graphite, sputter coated (Cu, TiZrV) graphite, and 316 LN stainless steel, were irradiated under grazing angle with 158 GeV/u indium ions. After a description of the new experimental set-up, the results of the pressure rise measurements are presented, and the derived desorption yields are compared with data from other experiments.2004http://cds.cern.ch/record/788532http://cds.cern.ch/record/788532oai:cds.cern.ch:788532 engRamos, DChauville, DKnaster, J RVeness, R J MCold Beam Vacuum Interconnects for the LHC Insertion RegionsAccelerators and Storage RingsLHC-Project-Report-740CERN-LHC-Project-Report-740The LHC machine is composed of arcs and insertion regions where superconducting magnets, working at temperatures of 1.9 K and 4.5 K, have flexibly interconnected beam vacuum chambers. These interconnects must respect strict requirements in terms of impedance, aperture, space optimization and reliability. A complete interconnect design was first developed for the arc regions, and from which a total of 20 variants have been created according to the different functional requirements of each pair of cryostats along the machine. All design features and manufacture processes were validated through extensive testing. Manufacture and assembly cost was minimised by using a modular interconnect design, with common components shared among different design variants. A detailed quality assurance structure was implemented in order to achieve the high level of reliability required. This paper presents the layout of cold beam vacuum interconnects along with details of development and testing performed to validate design and integration.2004-08-04http://cds.cern.ch/record/788531http://cds.cern.ch/record/788531oai:cds.cern.ch:788531 engCoccoli, MBuzio, MGarcía-Pérez, JLHC Dipole Axis, Spool Piece Alignment and Field Angle in Warm and Cold ConditionsAccelerators and Storage RingsLHC-Project-Report-739CERN-LHC-Project-Report-739The installation and commissioning of LHC requires knowledge of the magnetic alignment of the spool piece correctors mounted on the dipole end plates are, as well as of the dipole main field direction. The installation is based on the use of geometric information derived from mechanical measurements performed in warm conditions, assuming that geometric and magnetic axes coincide, and that thermal contractions of the assembly are homothetic. A series of measurements has been performed at room and superfluid Helium temperature to validate these assumptions. In this paper, a statistical analysis of the correlations obtained is presented for both corrector alignment and main field direction, and the results are compared with beam optics-based specifications.2004http://cds.cern.ch/record/788530http://cds.cern.ch/record/788530oai:cds.cern.ch:788530 engGranata, VBillan, JBordry, FrederickBottura, LCoutinho-Ferreira, P MEffinger, EFernqvist, GGalbraith, PKing, QPett, John GRaimondo, ARijllart, AThiesen, HMagnetic Field Tracking Experiments for LHCAccelerators and Storage RingsLHC-Project-Report-738CERN-LHC-Project-Report-738At the Large Hadron Collider (LHC) at CERN one of the difficult requirements during the energy ramp is that the ratio between the field produced by the quadrupoles and the field in the dipoles remains constant in order to minimize the variation of the betatron tune that could induce particle loss. With a series of tracking experiments it has been demonstrated that this ratio can be maintained constant to better than 10-4 throughout the same current ramp as foreseen for the LHC. A technique has been developed to optimise the dipole and quadrupole current ramps to obtain the required ratio of B2/B1. In addition measurements performed by modulating the current with a harmonic function (so-called k-modulation) demonstrated that it is possible to modulate the strength of an individual quadrupole to determine the magnetic center through beam-based measurements.2004-08-04http://cds.cern.ch/record/788522http://cds.cern.ch/record/788522oai:cds.cern.ch:788522 engBottura, LGranata, VFartoukh, Stéphane DavidTodesco, EzioA Strategy for Sampling the Field Quality of the LHC DipolesAccelerators and Storage RingsLHC-Project-Report-737CERN-LHC-Project-Report-737We have measured the magnetic field of a large fraction of the LHC main dipoles, to date more than 400 in warm conditions and over 100 in cold conditions. Using the available data we analysed the distributions of the main field and higher order field errors in warm and cold conditions, as well as the distribution of the warm-to-cold correlation. Based on this analysis we predict the minimum number of magnets that should be measured in cold conditions to insure that the LHC will meet its goals. The main outcome of this analysis is that cold measurements on a fraction of the order of one third of the total production, i.e. approximately 400 dipoles, will be sufficient to achieve the above objectives.2004http://cds.cern.ch/record/788521http://cds.cern.ch/record/788521oai:cds.cern.ch:788521 engChohan, VBuzio, Mde Rijk, GMiles, JPugnat, PRemondino, VittorioSanfilippo, SSiemko, ASmirnov, NVullierme, BWalckiers, LTesting of the LHC Magnets in Cryogenic Conditions: Current Experience and Near Future OutlookAccelerators and Storage RingsLHC-Project-Report-736CERN-LHC-Project-Report-736For the Large Hadron Collider under construction at CERN, a necessary and primordial condition prior to its installation is that all the main twin-aperture dipole and quadrupole magnets are tested in the 1.9 K cryogenic conditions. These tests are not feasible at the manufacturers and hence, are carried out at CERN at a purpose built facility on the site. This presentation will give an overall view of the issues related to the operation of the test facility. In particular, it will give the goals that need to be met to ensure the magnet integrity and performance and the context & constraints on the test programme. Results accumulated from the tested magnets and the ensuing tests stream-lining will be presented, together with some explanations and hard limits. Finally, some improvements planned for efficient operation will be given within the confines of the testing programme as was foreseen and the project goals and deadlines.2004http://cds.cern.ch/record/788520http://cds.cern.ch/record/788520oai:cds.cern.ch:788520 engCatalan-Lasheras, NKirby, G AOstojic, RPérez, J CPrin, HVenturini-Delsolaro, WPerformance of the Superconducting Matching Quadrupoles for the LHC InsertionsAccelerators and Storage RingsLHC-Project-Report-735CERN-LHC-Project-Report-735The optics flexibility of the LHC insertions is provided by the individually powered superconducting quadrupoles in the dispersion suppressors and matching sections. These cryo-magnets comprise special quadrupoles of the MQM and MQY type, and range in length from 5.4 m to 11.4 m. In total, 82 insertion quadrupoles will be assembled at CERN. In this paper we present the progress in fabrication and report on the performance of the first series quadrupoles. In particular, we present the quench performance of individual magnets and discuss the field quality trends and improvements based on magnet sorting.2004http://cds.cern.ch/record/788517http://cds.cern.ch/record/788517oai:cds.cern.ch:788517 engAllitt, MBagre, MGiloux, CKarppinen, MKhare, PLombardi, A MMaurya, TPuntambekar, ARemondino, VittorioSantrich-Badal, AVenturini-Delsolaro, WWolf, RField Quality and Hysteresis of LHC Superconducting Corrector MagnetsAccelerators and Storage RingsLHC-Project-Report-734CERN-LHC-Project-Report-734The Large Hadron Collider (LHC) will use some 7600 superconducting corrector magnets. The magnetic field quality is measured at room temperature by 12 magnetic measurement benches employed by the corrector manufacturers. CERN performs magnetic measurements at 4.2 K and at 1.9 K on a small subset of corrector magnets. The paper discusses the correlation between the warm and cold field measurements. The field quality is compared to the target field quality for LHC. Many corrector circuits will be powered in a way which cannot be predicted before LHC will start operation and which even then may change between physics runs. The measured magnetic hysteresis and its influence on possible setting errors during operation is discussed, in particular for the orbit correctors and the tuning/trim quadrupole magnet circuits.2004http://cds.cern.ch/record/788513http://cds.cern.ch/record/788513oai:cds.cern.ch:788513 engBozzini, DChareyre, VJacob, AMess, K HRussenschuck, StephanSolaz-Cerdan, RDesign of an Automatic System for the Electrical Quality Assurance during the Assembly of the Electrical Circuits of the LHCAccelerators and Storage RingsLHC-Project-Report-733CERN-LHC-Project-Report-733A method has been developed to verify automatically in the LHC tunnel the correct wiring of the 1712 circuits with about 70000 splices for the powering of all-together 10094 magnet units in the LHC machine. The test equipment first detects the continuity of a part of the electrical circuit and then verifies the polarity and type of the magnets connected in the circuit. A 108-meter LHC cell is the shortest unit that can be tested. The mobile system is composed of a unit placed at the centre of the cell and two de-multiplexers positioned at the extremities of the cell. The central unit contains a data acquisition system with a high precision digital multi-meter (DMM), switching matrixes and digital I/O ports to drive the de-multiplexers. In total 217 signals can be acquired and 3160 voltage combinations are possible. Pointing to different databases, a LabVIEW program automatically executes the test procedure and then generates and stores the reports. The hardware and software design, the data flow between databases, and the testing methodology applied to the different circuit types are described.2004http://cds.cern.ch/record/788510http://cds.cern.ch/record/788510oai:cds.cern.ch:788510 engGubello, GLa China, MScandale, WalterInstrumental Uncertainty in Measuring the Geometry of the LHC Main DipolesAccelerators and Storage RingsLHC-Project-Report-732CERN-LHC-Project-Report-732In the Large Hadron Collider 1232 superconducting dipoles will bend the two 7 TeV energy beams along a 27 km-long circular trajectory. The series production (assigned to three European firms) requires a well-defined procedure to check, in every magnet, the respect of the dimensional specifications. To verify tolerance of some tenths of millimeter over the 15-meter length in each cold mass, a laser tracker is necessarily used. To access the two beam apertures and to increase the measurement accuracies, the laser tracker is placed in different stations around the dipole defining a ’multi-station measuring procedure’. The noise affecting all the data taken so far suggested a careful analysis of the procedure itself. Through the computer modeling (based on a Montecarlo algorithm), the statistical error was quantified and compared to the experimental error. From this comparison the critical aspects of accuracy limitations from the multi-station procedure were better understood.2004http://cds.cern.ch/record/788508http://cds.cern.ch/record/788508oai:cds.cern.ch:788508 engMacCaferri, RFacchini, MJung, RTommasini, DVenturini-Delsolaro, WThe 5 T Superconducting Undulator for the LHC Synchrotron Radiation Profile MonitorAccelerators and Storage RingsLHC-Project-Report-731CERN-LHC-Project-Report-731A synchrotron radiation profile monitor will be used in the LHC to measure the beam profiles from the injection energy of 450 GeV to the nominal energy of 7 TeV. The radiation will be provided by a sequence of two separate magnets: a two-periods superconducting undulator and the beam separation dipole D3. After a short description of the profile monitor layout, the paper reviews the electromagnetic and mechanical design of the undulator, providing 5 T at 4.5 K in a 60 mm gap with a period of 280 mm and reports on the fabrication and cold test results of a first half period prototype.2004http://cds.cern.ch/record/788507http://cds.cern.ch/record/788507oai:cds.cern.ch:788507 engRossi, LExperience with LHC Magnets from Prototyping to Large Scale Industrial Production and IntegrationAccelerators and Storage RingsLHC-Project-Report-730CERN-LHC-Project-Report-730The construction of the LHC superconducting magnets is approaching its half way to completion. At the end of 2003, main dipoles cold masses for more than one octant were delivered; meanwhile the winding for the second octant was almost completed. The other large magnets, like the main quadrupoles and the insertion quadrupoles, have entered into series production as well. Providing more than 20 km of superconducting magnets, with the quality required for an accelerator like LHC, is an unprecedented challenge in term of complexity that has required many steps from the construction of 1 meterlong magnets in the laboratory to today’s production of more than one 15 meter-long magnet per day in Industry. The work and its organization is made even more complex by the fact that CERN supplies most of the critical components and part of the main tooling to the magnet manufacturers, both for cost reduction and for quality issues. In this paper the critical aspects of the construction will be reviewed and the actual achievements in term of quality and construction time will be compared with the expectations. The main result, the evidence of being able to meet the LHC schedule planned two years ago, as well as the efforts that are still needed to stick to it without loosing in quality will be discussed.2004http://cds.cern.ch/record/788506http://cds.cern.ch/record/788506oai:cds.cern.ch:788506 engWildner, EBeauquis, JGubello, GLa China, MScandale, WalterThe Geometry of the LHC Main DipoleAccelerators and Storage RingsLHC-Project-Report-729CERN-LHC-Project-Report-729The main lines of discussion and analysis for the LHC dipole geometry are related to the shape of the cold mass at different stages of production and tests. The limitations in the stability of the cold mass shape induces constraints for the positioning of the spool pieces (feed down effects), for the flanges (interconnectivity) and the overall shape (aperture considerations). The geometry after acceptance in industry may change by the time of measurements at CERN. Tolerances that are needed by hardware and by beam physics will be reviewed.2004http://cds.cern.ch/record/788505http://cds.cern.ch/record/788505oai:cds.cern.ch:788505 engBertinelli, FBoter, EFavre, GFerreira, L M ARossi, LSavary, FDesign and Fabrication of Superfluid Heat Exchanger Tubes for the LHC Superconducting MagnetsAccelerators and Storage RingsLHC-Project-Report-728CERN-LHC-Project-Report-728The dipole and quadrupole cold masses of the LHC machine require about 1 700 heat exchanger tubes (HET). In operation the HET carries a two-phase flow of superfluid helium at sub-atmospheric pressure. The HET consists of an oxygen-free, seamless copper tube equipped with stainless steel ends. After an evaluation of different alternatives, a design based on the technologies of vacuum brazing and electron beam welding has been adopted. Presence of these multiple technologies at CERN and synergies with the cleaning, handling and transport of other 15-metre components for LHC, motivated CERN to undertake this series fabrication on site. The raw copper tubes are procured in industry, presenting challenging issues of geometric precision. Organisation of the HET fabrication includes cryomeasurements to validate cleaning procedures, characterisation of welding procedures, design and experimental verification of buckling pressure, quality control during series production. The series fabrication of these long, multi-technological components is proceeding successfully, respecting the project’s tight budgetary and planning constraints.2004http://cds.cern.ch/record/788503http://cds.cern.ch/record/788503oai:cds.cern.ch:788503 engMarque, SColombet, TGenet, MSkoczen, BConnection Cryostats for LHC Dispersion SuppressorsAccelerators and Storage RingsLHC-Project-Report-727CERN-LHC-Project-Report-727The lattice of the Large Hadron Collider (LHC) being built at CERN is based on 8 standard arcs of 2.5 km length. Each arc is bounded on either side by Dispersion Suppressors connected to the arc by connection cryostats providing 15m long drift spaces. As for a dipole magnet, the connection cryostat provides a continuity of beam and insulation vacuum, electrical powering, cryogenic circuits, thermal and radiation shielding. In total 16 modules will be constructed. The stringent functional specification has led to various design options. Among them, a light mechanical structure has been developed with a stiffness comparable to that of a dipole magnet, for alignment purpose. Thermal studies, including lambda front propagation, have been performed to ensure a cooling down time to 1.9 K within the time budget. A special cooling scheme around the beam tubes has been chosen to cope with heat loads produced during operation. We report on the general design of these modules and on the adopted manufacturing process which guarantees the tight alignment of the beam tubes once the module is installed in the machine. Special emphasis is given on thermo-mechanical analysis, lambda front propagation and on the beam-tube cooling scheme.2004-08-04http://cds.cern.ch/record/788502http://cds.cern.ch/record/788502oai:cds.cern.ch:788502 engDutta, SDwivedi, JKumar, ASkoczen, BSoni, H CStructural Analysis of an Integrated Model of Short Straight Section, Service Module, Jumper Connection and Magnet Interconnects for the Large Hadron ColliderAccelerators and Storage RingsLHC-Project-Report-726CERN-LHC-Project-Report-726The Short Straight Section (SSS) of the Large Hadron Collider (LHC) may undergo relative displacements between cold-mass and cryostat for the following three reasons: - Fabrication tolerance of interconnection bellows - Global smoothing after pre-alignment - Ground motion in a sector of the LHC tunnel The forces responsible for such displacements stem from finite stiffness of interconnect bellows & metal hoses of the internal piping of the jumper connection and from relatively flexible 'glass fibre reinforced epoxy' (GFRE) composite supports of the cold mass. In addition, the vacuum jacket of the jumper connection and the large sleeves attached to both ends of SSS produce elastic deformations of the cryostat vessel. A unified finite element model consisting of cryostat, large sleeves, vacuum jacket of jumper, interconnection bellows, internal piping of jumper, composite cold supports and alignment jacks has been prepared. The knowledge of the position of the cold mass with respect to its cryostat under various conditions of alignment done using external fiducials mounted on the cryostat is essential. The maximum relative displacement for satisfactory machine operation is 0.1 mm. An SSS with cryogenic jumper connection has been modelled with the aim of assessing this possible displacement.2004http://cds.cern.ch/record/788501http://cds.cern.ch/record/788501oai:cds.cern.ch:788501 engDwivedi, JKumar, AGoswami, S GMadhumurthy, VParma, VSoni, H CThe Alignment Jacks of the LHC CryomagnetsAccelerators and Storage RingsLHC-Project-Report-725CERN-LHC-Project-Report-725The precise alignment of the 1232 dipoles, 474 Short Straight Sections (SSS) and some other components of the LHC collider, requires the use of 6800 jacks. The specific requirements and the need for a cost-effective solution for this large production, justified the development and industrialisation of a dedicated mechanical jack. The jack was developed, and is now being produced by Centre for Advanced Technology, India, in the framework of a collaboration between CERN and the Department of Atomic Energy in India. Three jacks support each of the 32-ton heavy, 15-meter long cryo-dipole of LHC, and provide the required alignment features. Identical jacks support the lighter LHC Short Straight Sections. Presently, the mass production of 6800 jacks is in progress with two Indian manufacturers, and 3545 jacks have already been delivered to CERN by April 2004. Considering the successful performance of the jacks, it is now envisaged to extend their use, with some modifications, for even higher-demanding alignment of the low-beta quadrupoles of the LHC.2004http://cds.cern.ch/record/788500http://cds.cern.ch/record/788500oai:cds.cern.ch:788500 engTock, J PBozzini, DLaurent, FRussenschuck, StephanSkoczen, BElectro-Mechanial Aspects of the Interconnection of the LHC Superconducting Corrector MagnetsAccelerators and Storage RingsLHC-Project-Report-724CERN-LHC-Project-Report-724In addition to the main 1232 bending dipoles and 474 focusing and defocusing quadrupoles, more than 6800 superconducting corrector magnets are included in the LHC machine. They are housed in the superfluid helium enclosures of the main cryomagnets. Among them, the closed orbit correctors (sextupole and octupole) are inte-grated in the main quadrupole helium vessel and they are powered via an externally routed cryogenic line (line-N). During machine assembly, these corrector magnets have to be connected according to a complex electrical scheme based on the optical requirements of the LHC. Along the 27-km long LHC, 440 interconnection boxes are installed and will allow the powering of the correctors by means of a 42-wire auxiliary bus-bars cable, of which the corresponding wires have to be routed to the main quadrupoles from the interconnection box. Stringent requirements in terms of volume, mechanical resistance, electrical conductance and insulation, reliability, and respect of the electrical schematics apply during the assembly and splicing of the junctions inside the line-N box. The activities and their sequence, aiming at ensuring the fulfilment of these requirements are presented. The planned activities (assembly, ultrasonic welding, general and electrical inspection, and electrical qualification) and the interactions between the various intervening teams are described.2004http://cds.cern.ch/record/788499http://cds.cern.ch/record/788499oai:cds.cern.ch:788499 engSkoczen, BKulka, JNon-Destructive Testing of Bus-Bar Joints Powering LHC Superconducting Magnets, by Using Gamma SourcesAccelerators and Storage RingsLHC-Project-Report-723CERN-LHC-Project-Report-723The main LHC superconducting magnets (dipoles and quadrupoles) use Rutherford type cables, stabilized electrically and thermally with copper profiles. The portions of cables are connected to each other by a soft soldering technique (Sn96Ag4) with an overlapping length corresponding to one pitch of the superconducting strands. The splice constitutes a "composite" structure with the interchanging layers of Sn96Ag4 and NbTi superconductor, located inside a Cu cage. In order to ensure a high level of reliability (failure probability not exceeding 10-8) for some 10000 connections in the LHC, a non-destructive technique to check the quantity of solder in the joint is foreseen. The technique is based on a gamma ray source (241Am) and the detection is position-sensitive in the transmission mode. Scintillating detectors of gamma rays are used and their accumulated length corresponds to the length of the radioactive source (120 mm). The method can be used in-situ, the equipment being optimized and portable, with implementation of direct on-line operation mode. The relevant criteria of acceptance of the splices have been defined. The first results of application of this technique are presented.2004http://cds.cern.ch/record/788498http://cds.cern.ch/record/788498oai:cds.cern.ch:788498 engBottura, LPieloni, TSanfilippo, SAmbrosio, GBauer, PHaverkamp, MA Scaling Law for Predicting Snap-Back in Superconducting Accelerator MagnetsAccelerators and Storage RingsCERN-AT-2004-016-MTMThe decay and snap-back of sextupole in the bending dipoles are issues of common concern, albeit at different levels of criticality, for all superconducting colliders built (Tevatron, HERA, RHIC) or in construction (LHC) to date. The main difficulty is the correction of the relatively large and fast sextupole change during snap-back. Motivated by the above considerations, we have pursued an extended study of sextupole snap-back on two different magnet families, the Tevatron and the LHC bending dipoles, using the same measurement method. We show here that it is possible to generalise the results obtained by using a simple, exponential scaling law. Furthermore, we show that for magnets of the same family the parameters of the scaling law correlate linearly. This finding could be exploited during accelerator operation to produce accurate forecast of the snap-back correction based solely on beam-based measurements.2004http://cds.cern.ch/record/788775http://cds.cern.ch/record/788775oai:cds.cern.ch:788775