Insertion Magnets

Chapter 3 in High-Luminosity Large Hadron Collider (HL-LHC) : Preliminary Design Report. The Large Hadron Collider (LHC) is one of the largest scientific instruments ever built. Since opening up a new energy frontier for exploration in 2010, it has gathered a global user community of about 7,000 scientists working in fundamental particle physics and the physics of hadronic matter at extreme temperature and density. To sustain and extend its discovery potential, the LHC will need a major upgrade in the 2020s. This will increase its luminosity (rate of collisions) by a factor of five beyond the original design value and the integrated luminosity (total collisions created) by a factor ten. The LHC is already a highly complex and exquisitely optimised machine so this upgrade must be carefully conceived and will require about ten years to implement. The new configuration, known as High Luminosity LHC (HL-LHC), will rely on a number of key innovations that push accelerator technology beyond its present limits. Among these are cutting-edge 11-12 tesla superconducting magnets, compact superconducting cavities for beam rotation with ultra-precise phase control, new technology and physical processes for beam collimation and 300 metre-long high-power superconducting links with negligible energy dissipation. The present document describes the technologies and components that will be used to realise the project and is intended to serve as the basis for the detailed engineering design of HL-LHC.Comment: 19 pages, Chapter 3 in High-Luminosity Large Hadron Collider (HL-LHC) : Preliminary Design Repor

Flow cytometric determination of genome size in European sunbleak Leucaspius delineatus (Heckel, 1843)

The aim of this study was to compare DNA content in hepatocyte and erythrocyte nuclei of the European sunbleak, Leucaspius delineatus, in relation to nuclear and cell size by means of flow cytometry and fluorescence microscopy. The DNA standards, chicken and rainbow trout erythrocytes, were prepared in parallel with both cell types, with initial separation of liver cells in pepsin solution followed by cell filtering. Standards and investigated cells were stained with a mixture of propidium iodide, citric acid, and Nonidet P40 in the presence of RNAse, and fluorescence of at least 50,000 nuclei was analyzed by flow cytometry. Average cell size was determined by flow cytometry, using fresh cell suspension in relation to latex beads of known diameter. The size of nuclei was examined on the basis of digital micrographs obtained by fluorescence microscopy after nuclei staining with DAPI. The sunbleak’s erythrocyte nuclei contain 2.25 ± 0.06 pg of DNA, whereas the hepatocyte nuclei contain 2.46 ± 0.06 pg of DNA. This difference in DNA content was determined spectroscopically using isolated DNA from the two cell types. The modal diameters of the erythrocytes and hepatocytes were estimated to be 5.1 ± 0.2 and 22.3 ± 5.0 μm, respectively, and the corresponding modal dimensions of their nuclei (measured as surface area) were 15.2 and 21.4 μm2, respectively. The nucleoplasmic index, as calculated from diameters estimated from surface area of nuclear profiles, was 2.51 for the erythrocytes compared with 0.08 for hepatocytes

Karyotype, morphology, and reproduction ability of the Prussian carp, Carassius gibelio (Actinopterygii: Cypriniformes: Cyprinidae) from unisexual and bisexual populations in Poland

Background. The majority of the European populations of the Prussian carp, Carassius gibelio, consist predominantly of females reproducing by gynogenesis but include a small portion of males. Mechanisms for the occurrence of males in natural populations and their functions are still unclear. The aims of this study were to show the ploidy level by karyotype, some taxonomic characteristics by analysis of morphology, and the reproductive potential by histology of gonads of Prussian carp individuals of a certain age from two types of naturally existing unisexual triploid and a diploid-polyploid populations. Materials and methods. In total 31 specimens from three different populations inhabiting the Vistula River basin, the Baltic Sea watershed, have been analyzed. Kidneys were used to prepare chromosome slides using standard procedures. Air-dried slides were stained with Giemsa solution. For each fish, 23 metric characteristics of the body were measured. Selected meristic characteristics (external and internal) were determined. The gonads were fixed in buffered formalin or in Bouin’s solution; histological sections were stained with haematoxylin and eosin (HE). The developmental stages of germ cells and gonads were determined according to Rinchard and Kestemont  and Billard. Results. All individuals of two populations were triploid females with high chromosomal variability from 150 to 160 chromosomes (and microchromosomes). Among individuals of the third population, males and females of 2n = 100 and one triploid male 3n = 160 (151–162) chromosomes were detected. The individuals from analyzed populations differed in the number of: branched rays in the dorsal fin, lateral line scales, serration in dorsal D and anal A fin rays, and vertebrae. Gonad histology of the ovaries indicated the females were mature at the age of 3. Testes morphology of diploids and one triploid male indicated their reproductive abilities. Conclusion. The results of the study confirmed the tendency to increase the number of males in C. gibelio populations. In several or some populations apart from diploid males a small number of fertile triploid males occur. High chromosomal variability within the females from unisexual populations may be influenced by their different mode of origin. The future research should be focused on karyological identification of other C. gibelio populations to explain the origin of triploid males and their role in reproduction

Support Structure Design of the Nb3_3Sn Quadrupole for the High Luminosity LHC

New low-β quadrupole magnets are being developed within the scope of the High Luminosity LHC (HL-LHC) project in collaboration with the US LARP program. The aim of the HL-LHC project is to study and implement machine upgrades necessary for increasing the luminosity of the LHC. The new quadrupoles, which are based on the Nb$_{3}$Sn superconducting technology, will be installed in the LHC Interaction Regions and will have to generate a gradient of 140 T/m in a coil aperture of 150 mm. In this paper, we describe the design of the short model magnet support structure and discuss results of the detailed 3D numerical analysis performed in preparation for the first short model test

Quench Protection of a Nb3Sn Superconducting Magnet System for a 45-GHz ECR Ion Source

Lawrence Berkeley National Laboratory in collaboration with the Institute of Modern Physics has developed a Nb Sn-based superconducting magnet system for a fourth-generation electron cyclotron resonance source, with a goal of achieving the magnetic field required for operating at the microwave frequency of 45 GHz. The magnet system is composed of one sextupole magnet inside three solenoids of different sizes manufactured from Nb Sn Sn round wire. Given the high stored energy density and relatively low wire copper fraction, the coils are not self-protected in the case of a quench. The study of the transient following a quench is carried out by means of the lumped-element dynamic electro-thermal program, which includes a detailed simulation of the interfilament coupling losses developing in the wire. Nonlinear effects occurring in the magnet, such as coupling loss and differential inductance reduction, have a significant impact on protecting these magnets. The resulting baseline quench protection strategy based on four independent energy extraction systems protecting the four magnets meets the quench protection requirements. Furthermore, in order to enhance the redundancy of the quench protection system and reduce the peak voltages to ground, the implementation of a coupling-loss induced quench (CLIQ) system is considered. 3

Assembly Tests of the First Nb3_{3}Sn Low-Beta Quadrupole Short Model for the Hi-Lumi LHC

In preparation for the high-luminosity upgrade of the Large Hadron Collider (LHC), the LHC Accelerator Research Program (LARP) in collaboration with CERN is pursuing the development of MQXF: a 150-mm-aperture high-field Nb$_{3}$Sn quadrupole magnet. The development phase starts with the fabrication and test of several short models (1.2-m magnetic length) and will continue with the development of several long prototypes. All of them are mechanically supported using a shell-based support structure, which has been extensively demonstrated on several R&D; models within LARP. The first short model MQXFS-AT has been assembled at LBNL with coils fabricated by LARP and CERN. In this paper, we summarize the assembly process and show how it relies strongly on experience acquired during the LARP 120-mm-aperture HQ magnet series. We present comparison between strain gauges data and finite-element model analysis. Finally, we present the implication of the MQXFS-AT experience on the design of the long prototype support structure

Quench Protection of a Nb3Sn Superconducting Magnet System for a 45-GHz ECR Ion Source

Lawrence Berkeley National Laboratory in collaboration with the Institute of Modern Physics has developed a Nb3Sn-based superconducting magnet system for a fourth-generation electron cyclotron resonance source, with a goal of achieving the magnetic field required for operating at the microwave frequency of 45 GHz. The magnet system is composed of one sextupole magnet inside three solenoids of different sizes manufactured from Nb3Sn Sn round wire. Given the high stored energy density and relatively low wire copper fraction, the coils are not self-protected in the case of a quench. The study of the transient following a quench is carried out by means of the lumped-element dynamic electro-thermal program, which includes a detailed simulation of the interfilament coupling losses developing in the wire. Nonlinear effects occurring in the magnet, such as coupling loss and differential inductance reduction, have a significant impact on protecting these magnets. The resulting baseline quench protection strategy based on four independent energy extraction systems protecting the four magnets meets the quench protection requirements. Furthermore, in order to enhance the redundancy of the quench protection system and reduce the peak voltages to ground, the implementation of a coupling-loss induced quench (CLIQ) system is considered