LINAC4 Commissioning Strategy (original) (raw)

Status and Plans for LINAC4 Installation and Commissioning

Linac4 is a normal conducting 160 MeV H¯ linear accelerator presently being installed and progressively commissioned at CERN. It will replace the ageing 50 MeV Linac2 as injector of the PS Booster (PSB), increasing at the same time its brightness by a factor of two thanks to the higher injection energy. This will be the first step of a program to increase the beam brightness in the LHC injectors for the needs of the High-Luminosity LHC project. After a series of beam measurements on a dedicated test stand the 3 MeV Linac4 front-end, including ion source, RFQ and a beam chopping line, has been recommissioned at its final position in the Linac4 tunnel. Commissioning of the following section, the Drift Tube Linac, is starting. Beam commissioning will take place in steps of increasing energy, to reach the final 160 MeV in 2015. An extended beam measurement phase including testing of stripping equipment for the PSB and a year-long test run to assess and improve Linac4 reliability will ta...

The LINAC4 Project at CERN

2011

As the first step of a long-term programme aiming at an increase in the LHC luminosity, CERN is building a new 160 MeV H¯ linear accelerator, Linac4, to replace the ageing 50 MeV Linac2 as injector to the PS Booster (PSB). Linac4 is an 86-m long normal-conducting linac made of an H¯ source, a Radio Frequency Quadrupole (RFQ), a chopping line and a sequence of three accelerating structures: a Drift-Tube Linac (DTL), a Cell-Coupled DTL (CCDTL) and a Pi-Mode Structure (PIMS). The civil engineering has been recently completed, and construction of the main accelerator components has started with the support of a network of international collaborations. The low-energy section up to 3 MeV including a 3-m long 352 MHz RFQ entirely built at CERN is in the final construction phase and is being installed on a dedicated test stand. The present schedule foresees beam commissioning of the accelerator in the new tunnel in 2013/14; the moment of connection of the new linac to the CERN accelerator chain will depend on the LHC schedule for long shut-downs.

The LINAC4 project: Overview and status

HHH- …, 2009

Linac4 is the new 160 MeV, 40 mA Haccelerator which will be the source of particles for all proton accelerators at CERN from 2013. Its construction has started in 2008, as part of a programme for the progressive replacement or upgrade of the LHC injectors during the next decade. Linac4 will initially inject into the PS Booster and at a later stage into a 4 GeV Superconducting Proton Linac (SPL), which could ultimately be upgraded to high duty cycle operation. For this reason accelerating structures, RF infrastructure and shielding of Linac4 are dimensioned for higher duty cycle from the initial phase.

Commissioning and Results of the Half-Sector Test Installation with 160 MeV H⁻ beam from Linac4

2017

During the Long Shutdown 2 (LS2) at CERN in 2019/20, the Proton Synchrotron Booster (PSB) will undergo a profound upgrade in the framework of the LHC Injector Upgrade (LIU) project involving also the connection to the new Linac4 injector. The 160 MeV Linac4 H − injection entails a complete replacement of the PSB injection section, including a stripping foil system, injection chicane, an H 0 /H − dump and novel beam instrumentation. The equivalent of half of this new injection chicane was temporarily installed in the Linac4 transfer line to evaluate the performance of the equipment and prepare controls, interlocks and applications for the connection. Outcomes of this so-called Half-Sector Test (HST) are presented in this paper.

Diagnostic Lines for the 160 MeV H Linac4 at CERN

Linac4 will be the new linear accelerator of the CERN accelerator chain delivering Hions at 160 MeV from 2016. The increased injection energy compared to the 50 MeV of its predecessor Linac2, combined with a Hcharge-exchange injection, will pave the way to reach ultimate goals for the LHC luminosity. Extensive commissioning of Linac4 is planned for the coming years. For this purpose, the beam will be studied after the exit of Linac4 in a straight line ending at the Linac4 dump, equipped with various beam instruments. An almost 180 m long transfer line will guide the beam to the charge-exchange injection point at the entry of the Proton Synchrotron Booster (PSB). About 50 m upstream of this point, two measurement lines will be upgraded to perform transverse emittance measurements as well as energy and energy spread measurements of the Linac4 beam. A detailed description of the beam measurement principles and setups at these three Linac4 diagnostics lines related to distinct Linac4 commissioning phases will be given.

Commissioning of the Beam Instrumentation for the Half Sector Test in Linac4 with a 160 MeV H⁻ Beam

2018

In the framework of the LHC Injector Upgrade (LIU) project, the Proton Synchrotron Booster (PSB) will be extensively modified during the Long Shutdown 2 (LS2, 2019-2020) at CERN [1]. This includes a new injector, Linac4, which will provide a 160 MeV H⁻ beam and a complete new injection section for the PSB composed essentially of a chicane and a stripping foil system. The equivalent of half of this new injection chicane, so-called Half-Sector Test (HST), was tempo-rarily installed in the Linac4 transfer line to evaluate the performance of the novel beam instrumentation, such as, stripping foils, monitoring screens, beam cur-rent transformers, H⁰/H⁻ monitor and dump, beam loss monitors, and beam position monitors. The results of the instrumentation commissioning of the HST are presented in this paper.

Status of the LINAC4 Project at CERN

The construction of Linac4, a 160 MeV H- Linac, is the first step in upgrading the LHC injector chain. Unlike CERN’s present injector linac, Linac4 will inject into the subsequent synchrotron via charge exchange injection. In a first stage, it will inject into the existing CERN PS Booster. At a later stage, Linac4 has the option to be extended by a superconducting linac (SPL) which could then inject into a new synchrotron (PS2). Construction of Linac4 has started in 2008, and beam operation is presently planned for 2015. An overview of the Linac4 main parameters and design choices is given, and the status of the construction reported.

Linac4 Beam Characterization before Injection into the CERN PS Booster

Construction work for the new CERN linear accelerator, Linac4, started in October 2008. Linac4 will replace the existing Linac2 and provide an H− beam at 160 MeV (as opposed to the present 50 MeV proton beam) for injection into the CERN PS Booster (PSB). The charge-exchange H− injection combined with the higher beam energy will allow for an increase in beam brightness required for reaching the ultimate LHC luminosity. Commissioning of Linac4 and of the transfer line to the PSB is planned for the last quarter of 2012. Appropriate beam instrumentation is foreseen to provide transverse and longitudinal beam characterization at the exit of Linac4 and in two dedicated measurement lines located before injection into the PSB. A detailed description of the diagnostics set, especially of spectrometer and emittance meter, and the upgrade of the measurement lines for Linac4 commissioning and operation is presented.

Design of LINAC4, a New Injector for the CERN Booster

A new H- linac (Linac4) is presently under study at CERN. This accelerator, based on normal conducting structures at 352 and 704 MHz, will provide a 30 mA 160 MeV H- beam to the CERN PS Booster (PSB), thus overcoming the present space-charge bottleneck at injection with a 50 MeV proton beam. Linac4 is conceived as the first stage of a future 2.2 GeV superconducting linac (SPL) and it is therefore designed for a higher duty cycle than necessary for the PSB. This paper discusses the design choices, presents the layout of the facility and illustrates the advantages for the LHC and other CERN users. The R&D and construction strategy, which mainly relies upon international collaborations, is also presented.

Overview of the CERN Linac4 beam instrumentation

The CERN LINAC4 will represent the first upgrade of the LHC injection chain, by accelerating H- ions from 45 KeV to 160 MeV for charge-exchange injection into the PS Booster. In order to provide its safe and efficient commissioning and operation, a wide variety of beam diagnostics devices has been designed for installation at convenient locations all over the accelerator length and in the transfer line to the PS Booster. This paper gives an overview of all instrumentation devices, including those to measure beam position, transverse and longitudinal profile, beam current and beam loss. The well advanced status of the system design and the main instrument features are discussed