Preliminary results of 3D-DDTC pixel detectors for the ATLAS upgrade

3D Silicon sensors fabricated at FBK-irst with the Double-side Double Type Column (DDTC) approach and columnar electrodes only partially etched through p-type substrates were tested in laboratory and in a 1.35 Tesla magnetic field with a 180GeV pion beam at CERN SPS. The substrate thickness of the sensors is about 200um, and different column depths are available, with overlaps between junction columns (etched from the front side) and ohmic columns (etched from the back side) in the range from 110um to 150um. The devices under test were bump bonded to the ATLAS Pixel readout chip (FEI3) at SELEX SI (Rome, Italy). We report leakage current and noise measurements, results of functional tests with Am241 gamma-ray sources, charge collection tests with Sr90 beta-source and an overview of preliminary results from the CERN beam test.Comment: 8 pages, 8 figures, presented at RD09 - 9th International Conference on Large Scale Applications and Radiation Hardness of Semiconductor Detectors, 30 September - 2 October 2009, Florence, Ital

The Compact Linear Collider (CLIC) - 2018 Summary Report

The Compact Linear Collider (CLIC) is a TeV-scale high-luminosity linear $e^+e^-$ collider under development at CERN. Following the CLIC conceptual design published in 2012, this report provides an overview of the CLIC project, its current status, and future developments. It presents the CLIC physics potential and reports on design, technology, and implementation aspects of the accelerator and the detector. CLIC is foreseen to be built and operated in stages, at centre-of-mass energies of 380 GeV, 1.5 TeV and 3 TeV, respectively. CLIC uses a two-beam acceleration scheme, in which 12 GHz accelerating structures are powered via a high-current drive beam. For the first stage, an alternative with X-band klystron powering is also considered. CLIC accelerator optimisation, technical developments and system tests have resulted in an increased energy efficiency (power around 170 MW) for the 380 GeV stage, together with a reduced cost estimate at the level of 6 billion CHF. The detector concept has been refined using improved software tools. Significant progress has been made on detector technology developments for the tracking and calorimetry systems. A wide range of CLIC physics studies has been conducted, both through full detector simulations and parametric studies, together providing a broad overview of the CLIC physics potential. Each of the three energy stages adds cornerstones of the full CLIC physics programme, such as Higgs width and couplings, top-quark properties, Higgs self-coupling, direct searches, and many precision electroweak measurements. The interpretation of the combined results gives crucial and accurate insight into new physics, largely complementary to LHC and HL-LHC. The construction of the first CLIC energy stage could start by 2026. First beams would be available by 2035, marking the beginning of a broad CLIC physics programme spanning 25-30 years

Surface Field Optimization of Accelerating Structures for CLIC Using ACE3P on Remote Computing Facility

This paper presents a computer program for searching for the optimum shape of an accelerating structure cell by scanning a multidimensional geometry parameter space. For each geometry, RF parameters and peak surface fields are calculated using ACE3P on a remote high-performance computational system. Parameter point selection, mesh generation, result storage and post-analysis are handled by a GUI program running on the user’s workstation. This paper describes the program, AcdOptiGui. AcdOptiGui also includes some capability for automatically selecting scan points based on results from earlier simulations, which enables rapid optimization of a given parameterized geometry. The software has previously been used as a part of the design process for accelerating structures for a 500 GeV CLIC

Design of an Accelerating Structure for a 500 GeV CLIC using ACE3P

An optimized design of the main linac accelerating structure for a 500 GeV first stage of CLIC is presented. A similar long-range wakefield suppression scheme as for 3 TeV CLIC based on heavy waveguide damping is adopted. The accelerating gradient for the lower energy machine is 80 MV/m. The 500 GeV design has larger aperture radius in order to increase the maximum bunch charge and length which is limited by the short-range wakefields. The cell geometries have been optimized using a new parametric optimizer for Ace3P and details of the RF cell design are described. Field parameters for the full structure are calculated using a power flow equation

Enhancing particle bunch-length measurements based on Radio Frequency Deflector by the use of focusing elements

A method to monitor the length of a particle bunch, based on the combination of a Radio Frequency Deflector (RFD) with magnetic focusing elements, is presented. With respect to state-of-the-art bunch length measurement, the additional focusing element allows to measure also the correlations between the longitudinal and transverse planes in terms of both position and divergence. Furthermore, the quadrupole-based focusing increases the input dynamic range of the measurement system (i.e. allows for a larger range of beam Twiss parameters at the entrance of the RFD). Thus, measurement resolution and precision are enhanced, by simultaneously preserving the accuracy. In this paper, the method is first introduced analytically, and then validated in simulation, by the reference tool ELEctron Generation ANd Tracking, ELEGANT. Finally, a preliminary experimental validation at CLEAR (CERN Linear Electron Accelerator for Research) is reported

Modeling the Low Level RF Response on the Beam during Crab Cavity Quench

The High Lu­mi­nos­ity Up­grade for the LHC (HL-LHC) re­lies on crab cav­i­ties to com­pen­sate for the lu­mi­nos­ity re­duc­tion due to the cross­ing angle of the col­lid­ing bunches at the in­ter­ac­tion points. In this paper we pre­sent the sim­u­la­tion stud­ies of cav­ity quenches and the im­pact on the beam. The cav­ity volt­age and phase dur­ing the quench is de­ter­mined from a sim­u­la­tion in Mat­lab and used to de­ter­mine the im­pact on the beam from track­ing sim­u­la­tions in Six­Track. The re­sults of this study are im­por­tant for de­ter­min­ing the re­quired ma­chine pro­tec­tion and in­ter­lock sys­tems for HL-LHC

Longitudinal Space Charge Effects in the CLIC Drive Beam

The CLIC main beam is accelerated by rf power generated from a high-intensity, low-energy electron drive beam. The accelerating fields are produced in Power Extraction and Transfer Structures, and are strongly dependent on the drive beam bunch distribution, as well as other parameters. We investigate how longitudinal space charge affects the bunch distribution and the corresponding power production, and discuss how the bunch length evolution can affect the main beam. We also describe the development of a Particle-in-Cell space charge solver which was used for the study

Witness electron beam injection using an active plasma lens for a proton beam-driven plasma wakefield accelerator

An active plasma lens (APL) focuses the beam in both the horizontal and vertical planes simultaneously using a magnetic field generated by a discharge current through the plasma. A beam size of 5-10 mu m can be achieved within a short distance using a focusing gradient on the order of 100 T/m. The APL is therefore an attractive element for plasma wakefield acceleration, because an ultrasmall size of the witness electron beam is required for injection into the plasma wakefield to minimize emittance growth and to enhance the capturing efficiency. When the drive beam and witness electron beam copropagate through the APL, interactions between the drive and witness beams, and the plasma must be considered. In this paper, through particle-in-cell simulations, we discuss the possibility of using an APL for the final focusing of the electron beam for the AWAKE RUN 2 experiments. It is confirmed that the amplitude of the plasma wakefield excited by proton bunches remains the same even after propagation through the APL. The emittance of the witness electron beam increases rapidly in the plasma density ramp regions of the lens. Nevertheless, when the witness electron beam has a charge of 100 pC, emittance of 10 mm mrad, and bunch length of 60 mu m, its emittance growth is not significant along the active plasma lens. For small emittance, such as 2 mm mrad, the emittance growth is found to be strongly dependent on the rms beam size, plasma density, and multiple Coulomb scattering