Low-charge-state linac

Energy Technology Data Exchange (ETDEWEB)

Shepard, K.W.; Kim, J.W.

1995-08-01

A design is being developed for a low-charge-state linac suitable for injecting ATLAS with a low-charge-state, radioactive beam. Initial work indicates that the existing ATLAS interdigital superconducting accelerating structures, together with the superconducting quadrupole transverse focussing element discussed above, provides a basis for a high-performance low-charge-state linac. The initial 2 or 3 MV of such a linac could be based on a normally-conducting, low-frequency RFQ, possibly combined with 24-MHz superconducting interdigital structures. Beam dynamics studies of the whole low-charge-state post-accelerator section were carried out in early FY 1995.

Machine Imperfection Studies of the RAON Superconducting Linac

Science.gov (United States)

Jeon, D.; Jang, J.-H.; Jin, H.

2018-05-01

Studies of the machine imperfections in the RAON superconducting linac (SCL) that employs normal conducting (NC) quadrupoles were done to assess the tolerable error budgets of the machine imperfections that ensure operation of the beam. The studies show that the beam loss requirement is met even before the orbit correction and that the beam loss requirement is met even without the MHB (multi-harmonic buncher) and VE (velocity equalizer) thanks to the RAON's radio-frequency quadrupole (RFQ) design feature. For the low energy section of the linac (SCL3), a comparison is made between the two superconducting linac lattice types: one lattice that employs NC quadrupoles and the other that employs SC solenoids. The studies show that both lattices meet the beam loss requirement after the orbit correction. However, before the orbit correction, the lattice employing SC solenoids does not meet the beam loss requirement and can cause a significant beam loss, while the lattice employing NC quadrupoles meets the requirement. For the lattice employing SC solenoids, care must be taken during the beam commissioning.

Linacs for medical and industrial applications

International Nuclear Information System (INIS)

Hamm, R.W.

1986-01-01

Linear accelerators for medical and industrial applications have become an important commercial business. Microwave electron linacs for cancer radiation therapy and high-energy industrial radiography form the bulk of this market, but these, as well as induction linacs, are now being offered for radiation processing applications such as sterilization of disposable medical products, food preservation and material modifications. The radio frequency quadrupole (RFQ) linac has now made the ion linac also practical for commercial applications in medicine and industry, including radiation therapy, isotope production, neutron production, materials modification, and energy transfer processes. Ion linacs for several of these applications will soon be commercially available. The market for both ion and electron linacs is expected to significantly grow in several exciting and important areas

Progress in design of the SNS linac

International Nuclear Information System (INIS)

Hardekopf, R.

2001-01-01

The Spallation Neutron Source (SNS) is a six-laboratory collaboration to build an intense pulsed neutron facility at Oak Ridge, TN. The linac design has evolved from the conceptual design presented in 1997 in order to achieve higher initial performance and to incorporate desirable upgrade features. The linac is now designed to produce 2-MW beam power using a combination of radio-frequency quadrupole (RFQ) linac, drift-tube linac (DTL), coupled-cavity linac (CCL), and superconducting-RF (SRF) linac. Designs of each of these elements support he high peak intensity and high quality beam required for injection into the SNS accumulator ring. This paper will trace the evolution of the linac design and the progress made in the R and D program. (author)

Beam characterization of a new continuous wave radio frequency quadrupole accelerator

Energy Technology Data Exchange (ETDEWEB)

Perry, A., E-mail: aperry4@hawk.iit.edu [Argonne National Laboratory, Argonne, IL 60439 (United States); Illinois Institute of Technology, Chicago, IL 60616 (United States); Dickerson, C.; Ostroumov, P.N.; Zinkann, G. [Argonne National Laboratory, Argonne, IL 60439 (United States)

2014-01-21

A new Continuous Wave (CW) Radio Frequency Quadrupole (RFQ) for the ATLAS (Argonne Tandem Linac Accelerator System) Intensity Upgrade was developed, built and tested at Argonne National Laboratory. We present here a characterization of the RFQ output beam in the longitudinal phase space, as well as a measurement of the transverse beam halo. Measurement results are compared to simulations performed using the beam dynamics code TRACK. -- Highlights: • Beam commissioning of a new CW RFQ has been performed at Argonne National Laboratory. • Energy spread and bunch shape measurements were conducted. • The formation of a beam halo in the transverse phase space was studied.

A high gradient superconducting quadrupole for a low charge state ion linac

International Nuclear Information System (INIS)

Kim, J.W.; Shepard, K.W.; Nolen, J.A.

1995-01-01

A superconducting quadrupole magnet has been designed for use as the focusing element in a low charge state linac proposed at Argonne. The expected field gradient is 350 T/m at an operating current of 53 A, and the bore diameter is 3 cm. The use of rare earth material holmium for pole tips provides about 10% more gradient then iron pole tips. The design and the status of construction of a prototype singlet magnet is described

Permanent magnet quadrupole for the 1-ST tank of LINAC-4

CERN Document Server

Skachkov, Vl; Sergeeva, O; Lombardi, A; Sargsyan, E; Cornuet, D; Venturini , W; Skachkov , V

2006-01-01

A rare-earth (REPM) ∅ 60 mm diameter, 45 mm long quadrupole for the LINAC-4 focusing channel with an integrated gradient of 2.3 T is described. Thin side washers are used for tuning the quad into specified gradient integral with ±0.5 % accuracy. The single washer contribution calculations are discussed. A method for limiting to 30 μ m the magnetic axis offset in the REPM quad is discussed to exclude its compensation by the outer diameter machining before inserting into the drift tube. Nonlinearity of the field is less than 1 % in the reference range of 75 % of beam aperture at the central cross- section near the quad axis . The angular quadrupole arrangement in the drift tube will be provided by machining the main groove on the quad surface in the median plane with 1 mrad accuracy. Calculations of the longitudinal gradient distribution between two...

Magnetic Qualification of Permanent Magnet Quadrupoles for CERN’s Linac4

CERN Document Server

Buzio, M; Lombardi, A; Mateo, F

2012-01-01

This paper summarizes the results of the magnetic measurements done to qualify prototypes and series permanent- magnet quadrupoles for the new Linac4, currently in construction at CERN. The results, obtained with a combination of stretched wire and rotating coil techniques, include the individually tuned integrated field gradient, multipoles, magnetic axis and field direction. These magnets are characterized by a challengingly small 22 mm aperture diameter and we illustrate the methods adopted to guarantee instrument calibration, along with the estimated accuracies of the measured quantities and their impact on beam optics.

Superconducting magnetic quadrupole

Energy Technology Data Exchange (ETDEWEB)

Kim, J.W.; Shepard, K.W.; Nolen, J.A.

1995-08-01

A design was developed for a 350 T/m, 2.6-cm clear aperture superconducting quadrupole focussing element for use in a very low q/m superconducting linac as discussed below. The quadrupole incorporates holmium pole tips, and a rectangular-section winding using standard commercially-available Nb-Ti wire. The magnet was modeled numerically using both 2D and 3D codes, as a basis for numerical ray tracing using the quadrupole as a linac element. Components for a prototype singlet are being procured during FY 1995.

Design and fabrication of the BNL radio frequency quadrupole

International Nuclear Information System (INIS)

McKenzie-Wilson, R.B.

1983-01-01

The Brookhaven National Laboratory polarized H - injection program for the AGS will utilize a Radio Frequency Quadrupole for acceleration between the polarized source and the Alvarez Linac. Although operation will commence with a few μ amperes of H - current, it is anticipated that future polarized H - sources will have a considerably improved output. The RFQ will operate at 201.25 MHz and will be capable of handling a beam current of 0.02 amperes with a duty cycle of 0.25%. The resulting low average power has allowed novel solutions to the problems of vane alignment, rf current contacts, and removal of heat from the vanes. The cavity design philosophy will be discussed together with the thermodynamics of heat removal from the vane. Details of the fabrication will be presented with a status report

Statistical simulations of machine errors for LINAC4

CERN Document Server

Baylac, M.; Froidefond, E.; Sargsyan, E.

2006-01-01

LINAC 4 is a normal conducting H- linac proposed at CERN to provide a higher proton flux to the CERN accelerator chain. It should replace the existing LINAC 2 as injector to the Proton Synchrotron Booster and can also operate in the future as the front end of the SPL, a 3.5 GeV Superconductingg Proton Linac. LINAC 4 consists of a Radio-Frequency Quadrupole, a chopper line, a Drift Tube Linac (DTL) and a Cell Coupled DTL all operating at 352 MHz and finally a Side Coupled Linac at 704 MHz. Beam dynamics was studied and optimized performing end-to-end simulations. This paper presents statistical simulations of machine errors which were performed in order to validate the proposed design.

Status of radio frequency quadrupole accelerator at IUAC, New Delhi

International Nuclear Information System (INIS)

Ahuja, Rajeev; Kothari, Ashok; Kumar, Sugam; Safvan, C.P.; Shankar, Ram

2015-01-01

As part of the accelerator augmentation program at IUAC, a High Current Injector (HCI) is being developed to inject highly charged ions into the superconducting LINAC. The HCI consists of a superconducting (High TC) ECR source, producing the high currents of highly charged ions. The ion beams produced will be injected into a Radio Frequency Quadrupole Accelerator (RFQ) and be accelerated to 180 keV/u. RF power of about 100 kW at 48.5 MHz will be fed to the RFQ during its actual working. The ions will be further accelerated by a Drift Tube Linac (DTL), before being further velocity matched with a low beta cavity into the superconducting LINAC. RFQ at IUAC is a four rod cavity structure having individual demountable copper vanes held on vane posts with a total vane length of 2.536 m and a minimum aperture of 12mm. The vane posts hold twenty nos. of vanes. Water will flow into vanes through the vane posts. The copper plated stainless steel vacuum housing has been divided into two chambers for the ease of fabrication and copper plating. The RFQ stand has provision for alignment in all the three axes. After successfully validating all the electrical and mechanical design parameters on a prototype RFQ, the fabrication of final RFQ has been completed. Initial assembly to check the mechanical accuracies was carried out. Low power RF tests were conducted to validate the design parameters. The resonance frequency of the RFQ was measured as 44.12 MHz and Q value was measured ∼ 5500. The final assembly is in progress. This paper details the present status and future plan of RFQ. (author)

Post-accelerator LINAC design for the VECC RIB project

Indian Academy of Sciences (India)

acclerator type of RIB facility. The scheme utilises the existing = 130 room temperature variable energy cyclotron machine as the primary accelerator for the production of RIBs and radio frequency quadrupole (RFQ) and LINAC modules for ...

Focussing magnets for proton Linac of ADS

International Nuclear Information System (INIS)

Malhotra, Sanjay; Mahapatra, U.; Singh, Pitamber; Choudhury, R.K.; Goel, Priyanshu; Verma, Vishnu; Bhattacharya, S.; Srivastava, G.P.; Kailas, S.; Sahni, V.C.

2009-01-01

A linear accelerator comprising of Radio frequency quadruple (RFQ) and drift tube linac (DTL) is being developed by BARC. The Alvarez type post-coupled cw DTL accelerates protons from an energy of 3 MeV to 20 MeV. The drift tube linac is excited in TM010 mode, wherein the particles are accelerated by longitudinal electric fields at the gap crossings between drift tubes. The particles are subjected to transverse RF defocusing forces at the gap crossings due to the increasing electric fields in the gap. The transverse defocusing is corrected by housing magnetic quadrupole focussing lenses inside the drift tubes. The permanent magnet quadrupoles (PMQs) are placed inside the hermetically sealed drift tubes and provide a constant magnetic field gradient in the beam aperture. This paper discusses various aspects of magnetic design, selection of magnetic materials and the engineering development involved in the prototype development of these drift tubes for proton Linac. (author)

RF quadrupole beam dynamics design studies

International Nuclear Information System (INIS)

Crandall, K.R.; Stokes, R.H.; Wangler, T.P.

1979-01-01

The radio-frequency quadrupole (RFQ) linear accelerator structure is expected to permit considerable flexibility in achieving linac design objectives at low velocities. Calculational studies show that the RFQ can accept a high-current, low-velocity, dc beam, bunch it with high efficiency, and accelerate it to a velocity suitable for injection into a drift-tube linac. Although it is relatively easy to generate a satisfactory design for an RFQ linac for low beam currents, the space-charge effects produced by high currents dominate the design criteria. Methods have been developed to generate solutions that make suitable compromises between the effects of emittance growth, transmission efficiency, and overall structure length. Results are given for a test RFQ linac operating at 425 MHz

Magnet innovations for linacs

International Nuclear Information System (INIS)

Halbach, K.

1986-01-01

It is possible to produce large magnetic fields at the aperture of permanent magnet quadrupoles, even when the magnetic aperture is very small. That, combined with their compactness, makes permanent magnet quadrupoles very powerful components of small aperture linacs. Results of past and present work on both fixed and variable strength permanent magnets suitable for use in and around linacs are presented

Magnet innovations for linacs

International Nuclear Information System (INIS)

Halbach, K.

1986-06-01

It is possible to produce large magnetic fields at the aperture of permanent magnet quadrupoles, even when the magnetic aperture is very small. That, combined with their compactness, makes permanent magnet quadrupoles very powerful components of small aperture linacs. Results will be presented about past and present work on both fixed and variable strength permanent magnets suitable for use in and around linacs

Variable-energy drift-tube linacs

International Nuclear Information System (INIS)

Swenson, D.A.; Boyd, T.J. Jr.; Potter, J.M.; Stovall, J.E.

1982-01-01

Practical applications of ion linacs are more viable now than ever before because of the recent development of the radio-frequency quadrupole accelerating structure, as well as other technological advances developed under the Pion Generator for Medical Irradiations program. This report describes a practical technique for varying the energy of drift-tube linacs and thus further broadening the possibilities for linac applications. This technique involves using the post couplers (normally used to flatten and stabilize the electric fields) to create a step in the fields, thus terminating the acceleration process. In the examples given for a 70-MeV accelerator design, when using this technique the energy is continually variable down to 20 MeV, while maintaining a small energy spread

Operational parameters of a 2.0-MeV RFQ linac

International Nuclear Information System (INIS)

Sander, O.R.; Purser, F.O.; Rusthoi, D.P.

1984-01-01

After extensive upgrading, our radio-frequency quadrupole (RFQ) linac is again installed on the accelerator test stand (ATS). The measured parameters of the RFQ, such as the output transverse emittance, transmitted beam, average energy, and energy spread is presented

Integrated design of the SSC linac injector

International Nuclear Information System (INIS)

Evans, D.; Valiecnti, R.; Wood, F.

1992-01-01

The Ion Source, Low Energy Beam Transport (LEBT), and Radio Frequency Quadrupole (RFQ) of the Superconducting Super Collider (SSC) Linac act as a unit (referred to as the Linac Injector), the Ion Source and LEBT being cantilevered off of the RFQ. Immediately adjacent to both ends of the RFQ cavity proper are endwall chambers containing beam instrumentation and independently-operated vacuum isolation valves. The Linac Injector delivers 30 mA of H - beam at 2.5 MeV. This paper describes the design constraints imposed on the endwalls, aspects of the integration of the Ion Source and LEBT including attachment to the RFQ, maintainability and interchangeability of LEBTs, vacuum systems for each component, and the design of necessary support structure. (Author) 2 tab

Design and fabrication of Radio Frequency Quadrupole (RFQ) Accelerator at IUAC, New Delhi

International Nuclear Information System (INIS)

Ahuja, R.; Kothari, A.; Safvan, C.P.; Kumar, Sugam; Ram Sankar, P.

2013-01-01

As part of the accelerator augmentation program at Inter-University Accelerator Centre (IUAC), a high current injector (HCI) is being developed to inject high currents of highly charged ions into the superconducting LINAC. The ion beams produced by the Electron Cyclotron Resonance (ECR) based PKDELIS ion source will be injected into a Radio Frequency Quadrupole Accelerator (RFQ). The RFQ focuses and accelerates the ion beam. For the development of the RFQ Accelerator, a prototype of nearly half length was successfully built at IUAC to test the RF, thermal and mechanical design. The prototype is designed for 30 kW power at 48.5 MHz. This paper presents the mechanical design, fabrication and assembly of the final 2.5 m long RFQ. (author)

Linac4 RFQ assembly is carried out before installation in Building 152

CERN Multimedia

Anna Pantelia

2012-01-01

This series of pictures documents the assembly phase of the Linac4 RFQ (Radio Frequency Quadrupole), performed at the end of July 2012. The Linac4 RFQ is made of 3 modules, 1 meter each, assembled together to accelerate the H- or proton beam from the ion source extraction at 45 kV to the energy of 3 MeV. The RFQ is the first of the Linac4 accelerating structures, which will increase to 160 MeV the beam injection energy into the PS Booster as from the end of LS2.

Error studies for SNS Linac. Part 1: Transverse errors

International Nuclear Information System (INIS)

Crandall, K.R.

1998-01-01

The SNS linac consist of a radio-frequency quadrupole (RFQ), a drift-tube linac (DTL), a coupled-cavity drift-tube linac (CCDTL) and a coupled-cavity linac (CCL). The RFQ and DTL are operated at 402.5 MHz; the CCDTL and CCL are operated at 805 MHz. Between the RFQ and DTL is a medium-energy beam-transport system (MEBT). This error study is concerned with the DTL, CCDTL and CCL, and each will be analyzed separately. In fact, the CCL is divided into two sections, and each of these will be analyzed separately. The types of errors considered here are those that affect the transverse characteristics of the beam. The errors that cause the beam center to be displaced from the linac axis are quad displacements and quad tilts. The errors that cause mismatches are quad gradient errors and quad rotations (roll)

Vibrational Stability of NLC Linac and Final Focus Components

Energy Technology Data Exchange (ETDEWEB)

Le Pimpec, Frederic

2002-09-25

Vertical vibration of linac components (accelerating structures, girders and quadrupoles) in the NLC has been studied experimentally and analytically. Effects such as structural resonances and vibration caused by cooling water both in accelerating structure and quadrupoles have been considered. Experimental data has been compared with analytical predictions and simulations using ANSYS. Design to properly decouple the structure vibrations from the linac quadrupoles is being pursued.

Mechanical features of a 700 MHz bridge-coupled drift tube linac

International Nuclear Information System (INIS)

Liska, D.; Smith, P.; Carlisle, L.; Larkin, T.; Lawrence, G.; Garnett, R.

1992-01-01

Modem linac designs for treating radioactive waste achieve high proton currents through funneling at low energy, typically around 20 MeV. The resulting switch to a high-frequency accelerating structure poses severe performance and fabrication difficulties below 100 MeV. Above 100 MeV, proven coupled-cavity linacs (CCLS) are available. However, at 20 MeV one must choose between a high-frequency drift-tube linac (DTL) or a coupled-cavity linac with very short cells. Potential radiation damage from the CW beam, excessive RF power losses, multipactoring, and fabricability all enter into this decision. At Los Alamos, we have developed designs for a bridge-coupled DTL (BCDTL) that, like a CCL, uses lattice focusing elements and bridge couplers, but that unlike a CCL, accelerates the beam in simple, short, large-aperture DTL modules with no internal quadrupole focusing. Thus, the BCDTL consumes less power than the CCL linac without beam performance and is simpler and cheaper to fabricate in the 20 to 100 MeV range

Overview and status of RF systems for the SSC Linac

International Nuclear Information System (INIS)

Mynk, J.; Grippe, J.; Cutler, R.I.; Rodriguez, R.

1993-05-01

The Superconducting Super Collider (SSC) Linear Accelerator (Linac) produces a 600-MeV, 35-μs, H-beam at a 10-Hz repetition rate. The beam is accelerated by a series of RF cavities. These consist of a Radio Frequency Quadrupole (RFQ), two bunchers, and four Drift Tube Linac (DTL) tanks at 427.617 MHz, and two bunchers, nine side-coupled Linac modules, and an energy compressor at 1282.851 MHz. The RFQ amplifier and the low-frequency buncher cavity amplifiers use gridded tubes, while the other cavities use klystron amplifier systems. The RF control system consists of a reference line and cavity feedback and feedforward loops for each amplifier. The RF amplifier system for each of these accelerator cavities is described, and the current status of each system is presented

The LINAC4 Project at CERN

CERN Document Server

Arnaudon, L; Bertone, C; Body, Y; Broere, J; Brunner, O; Buzio, M; Carli, C; Caspers, F; Corso, JP; Coupard, J; Dallocchio, A; Dos Santos, N; Garoby, R; Gerigk, F; Hammouti, L; Hanke, K; Jones, M; Kozsar, I; Lettry, J; Lallement, JB; Lombardi, A; Lopez-Hernandez, LA; Maglioni, C; Mathot, S; Maury, S; Mikulec, B; Nisbet, D; Noels, C; Paoluzzi, M; Puccio, B; Raich, U; Ramberger, S; Rossi, C; Schwerg, N; Scrivens, R; Vandoni, G; Weisz, S; Vollaire, J; Vretenar, M; Zickler, T

2011-01-01

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 L...

Effect of cooling water on stability of NLC linac components

Energy Technology Data Exchange (ETDEWEB)

F. Le Pimpec et al.

2003-02-11

Vertical vibration of linac components (accelerating structures, girders and quadrupoles) in the NLC has been studied experimentally and analytically. Effects such as structural resonances and vibration caused by cooling water both in accelerating structures and quadrupoles have been considered. Experimental data has been compared with analytical predictions and simulations using ANSYS. A design, incorporating the proper decoupling of structure vibrations from the linac quadrupoles, is being pursued.

Effect of Cooling Water on Stability of NLC Linac Components

Energy Technology Data Exchange (ETDEWEB)

Le Pimpec, Frederic

2002-11-01

Vertical vibration of linac components (accelerating structures, girders and quadrupoles) in the NLC has been studied experimentally and analytically. Effects such as structural resonances and vibration caused by cooling water both in accelerating structures and quadrupoles have been considered. Experimental data has been compared with analytical predictions and simulations using ANSYS. A design, incorporating the proper decoupling of structure vibrations from the linac quadrupoles, is being pursued.

Mechanical features of a 700-MHz bridge-coupled drift-tube linac

International Nuclear Information System (INIS)

Liska, D.; Smith, P.; Carlisle, L.; Larkin, T.; Lawrence, G.; Garnett, R.

1992-01-01

Modern linac designs for treating radioactive waste achieve high proton currents through funneling at low energy, typically around 20 MeV. The resulting switch to a high-frequency accelerating structure poses severe performance and fabrication difficulties below 100 MeV. Above 100 MeV, proven coupled-cavity linacs (CCLs) are available. However, at 20 MeV one must choose between a high-frequency drift-tube linac (DTL) or a coupled-cavity linac with very short cells. Potential radiation damage from the CW beam, excessive RF power losses, multipactoring, and fabricability all enter into this decision. At Los Alamos, we have developed designs for a bridge-coupled DTL (BCDTL) that, like a CCL, uses lattice focusing elements and bridge couplers, but that unlike a CCL, accelerates the beam in simple, short, large-aperture DTL modules with no internal quadrupole focusing. Thus, the BCDTL consumes less power than the CCL linac without beam performance and is simpler and cheaper to fabricate in the 20 to 100 MeV range. (Author) ref., tab., 3 figs

An automatic frequency control system of 2-MeV electronic LINAC

International Nuclear Information System (INIS)

Hu Xue; Zhang Junqiang; Zhong Shaopeng; Zhao Minghua

2013-01-01

Background: In electronic LINAC, the magnetron is often used as power source. The output frequency of magnetron always changes with the environment and the frequency difference between the output of magnetron and the frequency of accelerator, which will result in the bad performance of LINAC systems. Purpose: To ensure the performance of the work of entire LINAC system effectively, an automatic frequency control system is necessary. Methods: A phase locked frequency discriminator is designed to discriminate the frequency of accelerator guide and magnetron, and analogue circuit is used to process the output signals of frequency discriminator unit. Results: Working with the automatic frequency control (AFC) system, the output frequency of magnetron can be controlled in the range of (2998 MHz, 2998 MHz + 70 kHz) and (2998 MHz, 2998 MHz - 30 kHz). Conclusions: Under the measurement and debug, the functionality of frequency discriminator unit and signal processor circuit is tested effectively. (authors)

Study on pulsed-operation of the drift tube quadrupole magnets

International Nuclear Information System (INIS)

Mutou, M.

1982-01-01

The heavy ion linac for NUMATRON project is designed not only as a injector for a synchrotron but also as a supplier of heavy ion beams for experiments with linac beam. In one repetition cycle of the synchrotron (1sec), the linac injects nearly 25 beam pulses with pulse width of 300 μsec and pulse interval of 30 msec. And the ion species can be varied every repetition. On the other hand, when it is off duty of injection to the synchrotron, the linac accelerates the beams that are directly used for the experiments. Also in this case, the ion species should be varied according to the requests of the experiments, for instance every 1 sec. Therefore, the quadrupole magnets installed in the drift tubes of the linac must be excited with pulse mode. The power supply of the quadrupole magnets will consists of two parts, namely pulse-excitation and dc-excitation power sources. The report describes the posibilities on the pulse-operation of the quadrupole magnets with the field gradient of asymptotically equals 10 KG/cm, and the analysis of the power supply of the quadrupole magnets. (author)

Redesign of the low energy section of the Fermilab linac to improve beam brightness

International Nuclear Information System (INIS)

Schmidt, C.; Noble, R.; Palkovic, J.; Mills, F.E.

1988-10-01

The critical parameters which limit the luminosity of the Fermilab Tevatron Collider are the beam emittances, both longitudinal and transverse, at each stage in the acceleration sequence. Improvements to reduce invariant emittance growth at earlier acceleration stages necessarily encourage improvements in all downstream stages. Recent advances in linac technology should permit a significant increase in the beam brightness of the Fermilab linac. A redesign of the low energy section of the linac is envisioned to include a circular aperture H/sup /minus// source, a short 30-keV transport line (solenoids, Gabor lenses or einzel lenses) for matching to a radio frequency quadrupole linac (RFQ), and injection at approximately 2 MeV into a new 200 MHz Alvarez linac tank for acceleration to 10 MeV. 9 refs., 1 fig

Design of RF structures for a superconducting proton linac

International Nuclear Information System (INIS)

Pande, Rajni; Roy, Shweta; Rao, S.V.L.S.; Krishnagopal, S.; Singh, P.

2013-01-01

One of the main components of the Accelerator Driven System (ADS) programme in India is a 1 GeV, high intensity CW proton accelerator that will be superconducting after the radio-frequency quadrupole (RFQ), i.e. after 3 MeV. The superconducting linac will consist of various superconducting structures like Half Wave Resonators, Spoke Resonators and elliptical cavities, operating at RF frequencies of 162.5 MHz, 325 MHz and 650 MHz. The paper will discuss the optimization of the electromagnetic design of the various superconducting structures. (author)

Dispersion and betatron matching into the linac

International Nuclear Information System (INIS)

Decker, F.J.; Adolphsen, C.; Corbett, W.J.; Emma, P.; Hsu, I.; Moshammer, H.; Seeman, J.T.; Spence, W.L.

1991-05-01

In high energy linear colliders, the low emittance beam from a damping ring has to be preserved all the way to the linac, in the linac and to the interaction point. In particular, the Ring-To-Linac (RTL) section of the SLAC Linear Collider (SLC) should provide an exact betatron and dispersion match from the damping ring to the linac. A beam with a non-zero dispersion shows up immediately as an increased emittance, while with a betatron mismatch the beam filaments in the linac. Experimental tests and tuning procedures have shown that the linearized beta matching algorithms are insufficient if the actual transport line has some unknown errors not included in the model. Also, adjusting quadrupole strengths steers the beam if it is offset in the quadrupole magnets. These and other effects have lead to a lengthy tuning process, which in the end improves the matching, but is not optimal. Different ideas will be discussed which should improve this matching procedure and make it a more reliable, faster and simpler process. 5 refs., 2 figs

Conceptual study of high power proton linac for accelerator driven subcritical nuclear power system

CERN Document Server

Yu Qi; Ouyang Hua Fu; Xu Tao Guang

2001-01-01

As a prior option of the next generation of energy source, the accelerator driven subcritical nuclear power system (ADS) can use efficiently the uranium and thorium resource, transmute the high-level long-lived radioactive wastes and raise nuclear safety. The ADS accelerator should provide the proton beam with tens megawatts. The superconducting linac is a good selection of ADS accelerator because of its high efficiency and low beam loss rate. The ADS accelerator presented by the consists of a 5 MeV radio-frequency quadrupole, a 100 MeV independently phased superconducting cavity linac and a 1 GeV elliptical superconducting cavity linac. The accelerating structures and main parameters are determined and the research and development plan is considered

Physics design of APT linac with normal conducting rf cavities

International Nuclear Information System (INIS)

Nath, S.; Billen, J.H.; Stovall, J.E.; Takeda, Harunori; Young, L.M.

1996-01-01

The accelerator based production of tritium calls for a high-power, cw proton linac. Previous designs for such a linac use a radiofrequency quadrupole (RFQ), followed by a drift-tube linac (DTL) to an intermediate energy and a coupled-cavity linc (CCL) to the final energy. The Los Alamos design uses a high-energy (6.7 MeV) RFQ followed by the newly developed coupled-cavity drift-tube linac (CCDTL) and a CCL. This design accommodates external electromagnetic quadrupole lenses which provide a strong uniform focusing lattice from the end of the RFQ to the end of the CCL. The cell lengths in linacs of traditional design are typically graded as a function of particle velocity. By making groups of cells symmetric in both the CCDTL and CCL, the cavity design as well as mechanical design and fabrication is simplified without compromising the performance. At higher energies, there are some advantages of using superconducting rf cavities. Currently, such schemes are under vigorous study. This paper describes the linac design based on normal conducting cavities and presents simulation results

Conceptual study of high power proton linac for accelerator driven subcritical nuclear power system

International Nuclear Information System (INIS)

Yu Qingchang; Ouyang Huafu; Xu Taoguang

2002-01-01

As a prior option of the next generation of energy source, the accelerator driven subcritical nuclear power system (ADS) can use efficiently the uranium and thorium resource, transmute the high-level long-lived radioactive wastes and raise nuclear safety. The ADS accelerator should provide the proton beam with tens megawatts. The superconducting linac is a good selection of ADS accelerator because of its high efficiency and low beam loss rate. The ADS accelerator presented by the authors consists of a 5 MeV radio-frequency quadrupole, a 100 MeV independently phased superconducting cavity linac and a 1 GeV elliptical superconducting cavity linac. The accelerating structures and main parameters are determined and the research and development plan is considered

A 2--4 nm Linac Coherent Light Source (LCLS) using the SLAC linac

International Nuclear Information System (INIS)

Winick, H.; Bane, K.; Boyce, R.

1993-05-01

We describe the use of the SLAC linac to drive a unique, powerful. short wavelength Linac Coherent Light Source (LCLS). Operating as an FEL, lasing would be achieved in a single pass of a high peak current electron beam through a long undulator by self-amplified spontaneous emission (SASE). The main components are a high-brightness rf photocathode electron gun; pulse compressors; about 1/5 of the SLAC linac; and a long undulator with a FODO quadrupole focussing system. Using electrons below 8 GeV, the system would operate at wavelengths down to about 3 nm, producing ≥10 GW peak power in sub-ps pulses. At a 120 Hz rate the average power is ∼ 1 W

Comparison of LINAC-4 Designs

CERN Document Server

Crandall, K; Sargsyan, E; Lallement, J-B; CERN. Geneva. BE Department

2009-01-01

We have studied the expected performance of two drift tube linac (DTL) designs proposed for LINAC-4. The two designs use the same cell geometries but are characterized by different phase (φs) and accelerating field (E0) distributions. In addition we have investigated the expected performance of 3 different quadrupole focusing schemes in each design. The expected performance of these 6 variants is compared with respect to their stability and risk of beam loss with alignment errors.

Smooth transverse and longitudinal focusing in high-intensity ion linacs

International Nuclear Information System (INIS)

Billen, J.H.; Takeda, Harunori; Young, L.M.

1996-01-01

We examine ion linac designs that start with a high energy radio- frequency quadrupole (RFQ) followed by either a drift-tube linac (DTL) or a coupled-cavity drift-tube linac (CCDTL). For high energies a conventional CCL follows the CCDTL. High RFQ output energy allows tailoring the transverse and longitudinal focusing strengths to match into the following structure. When the RFQ beam enters a higher frequency structure, the DTL or CCDTL starts with a low accelerating gradient and large negative synchronous phase. The gradient and phase both ramp up gradually to higher values. Other changes later in the machine are also gradual. Beam dynamics simulations show that these linacs require no separate matching sections. Applications include a cw 100 mA H + beam from a 350-MHz, 6.7 MeV RFQ injecting a 700 MHz CCDTL and CCL; a 7% duty 28 mA H - beam from a 402.5 MHz RFQ and DTL injecting 805 MHz structures; a cw 135 mA D + beam produced by a 175 MHz, 8 MeV RFQ and DTL; and a 2.4% duty, 80 mA H + beam using a 433 MHz 10 MeV RFQ and a 1300 MHz CCDTL. The machines take advantage of the considerable flexibility of the CCDTL. Designs can use a variety of different transverse focusing lattices. Use of two coupling cavity orientations permits a constant period even when the number of drift tubes per cavity changes along the linac

H- Ion Sources For CERN’s Linac4

CERN Document Server

Lettry, J; Coutron, Y; Chaudeta, E; Dallocchio, A; Gil Flores, J; Hansen, J; Mahner, E; Mathot, S; Mattei, S; Midttun, O; Moyret, P; Nisbet, D; O’Neil, M; Paoluzzi, M; Pasquino, C; Pereira, H; Sanchez Arias, J; Schmitzer, C; Scrivens, R; Steyaert, D

2013-01-01

The specifications set to the Linac4 ion source are: H- ion pulses of 0.5 ms duration, 80 mA intensity and 45 keV energy within a normalized emittance of 0.25 mmmrad RMS at a repetition rate of 2 Hz. In 2010, during the commissioning of a prototype based on H- production from the plasma volume, it was observed that the powerful co-extracted electron beam inherent to this type of ion source could destroy its electron beam dump well before reaching nominal parameters. However, the same source was able to provide 80 mA of protons mixed with a small fraction of H2+ and H3+ molecular ions. The commissioning of the radio frequency quadrupole accelerator (RFQ), beam chopper and H- beam diagnostics of the Linac4 are scheduled for 2012 and its final installation in the underground building is to start in 2013. Therefore, a crash program was launched in 2010 and reviewed in 2011 aiming at keeping the original Linac4 schedule with the following deliverables: Design and production of a volume ion source prototype suitabl...

Status and Operation of the Linac4 Ion Source Prototypes

CERN Document Server

Lettry, J; Andersson, P; Bertolo, S; Butterworth, A; Coutron, Y; Dallocchio, A; Chaudet, E; Gil-Flores, J; Guida, R; Hansen, J; Hatayama, A; Koszar, I; Mahner, E; Mastrostefano, C; Mathot, S; Mattei, S; Midttun, O; Moyret, P; Nisbet, D; Nishida, K; O’Neil, M; Ohta, M; Paoluzzi, M; Pasquino, C; Pereira, H; Rochez, J; Sanchez Alvarez, J; Sanchez Arias, J; Scrivens, R; Shibata, T; Steyaert, D; Thaus, N; Yamamoto, T

2014-01-01

CERN’s Linac4 45 kV H- ion sources prototypes are installed at a dedicated ion source test stand and in the Linac4 tunnel. The operation of the pulsed hydrogen injection, RF sustained plasma and pulsed high voltages are described. The first experimental results of two prototypes relying on 2MHz RF- plasma heating are presented. The plasma is ignited via capacitive coupling, and sustained by inductive coupling. The light emitted from the plasma is collected by viewports pointing to the plasma chamber wall in the middle of the RF solenoid and to the plasma chamber axis. Preliminary measurements of optical emission spectroscopy and photometry of the plasma have been performed. The design of a cesiated ion source is presented. The volume source has produced a 45 keV H- beam of 16-22 mA which has successfully been used for the commissioning of the Low Energy Beam Transport (LEBT), Radio Frequency Quadrupole (RFQ) accelerator and chopper of Linac4.

A new RFQ linac fabrication technique

International Nuclear Information System (INIS)

Schrage, D.; Roybal, P.; Young, L.; Clark, W.; DePaula, R.; Martinez, F.

1994-01-01

The use of hydrogen furnace brazing has been applied as a joining technology to the fabrication of a Radio-Frequency-Quadrupole (RFQ) linac for the Los Alamos Accelerator Performance Demonstration Facility (APDF). The design concept provides a monolithic cavity with no longitudinal rf, vacuum, or mechanical joints. A 530 MHz, 0.46 meter long engineering model RFQ has been fabricated and tested at the Los Alamos National Laboratory as a technical demonstration of this concept. It is planned that two funneled RFQ's for the APDF (7 MeV, 350 MHz, 100 mAmp CW, each eight meters in length) will be manufactured by this method

An improved permanent magnet quadrupole design with larger good field region for high intensity proton linacs

Energy Technology Data Exchange (ETDEWEB)

Mathew, Jose V., E-mail: josev.mathew@gmail.com; Rao, S.V.L.S.; Krishnagopal, S.; Singh, P.

2013-11-01

The Low Energy High Intensity Proton Accelerator (LEHIPA), being developed at the Bhabha Atomic Research Centre (BARC) will produce a 20 MeV, 30 mA, continuous wave (CW) proton beam. At these low velocities, space-charge forces dominate, and could lead to larger beam sizes and beam halos. Hence in the design of the focusing lattice of the LEHIPA drift tube linac (DTL) using permanent magnet quadrupoles (PMQs), a larger good field region is preferred. Here we study, using the two dimensional (2D) and three dimensional (3D) simulation codes PANDIRA and RADIA, four different types of cylindrical PMQ designs: 16-segment trapezoidal Halbach configuration, bullet-nosed geometry and 8- and 16-segment rectangular geometries. The trapezoidal Halbach geometry is used in a variety of accelerators since it provides very high field gradients in small bores, while the bullet-nosed geometry, which is a combination of the trapezoidal and rectangular designs, is used in some DTLs. This study shows that a larger good field region is possible in the 16-segment rectangular design as compared to the Halbach and bullet-nosed designs, making it more attractive for high-intensity proton linacs. An improvement in good-field region by ∼16% over the Halbach design is obtained in the optimized 16-segment rectangular design, although the field gradient is lower by ∼20%. Tolerance studies show that the rectangular segment PMQ design is substantially less sensitive to the easy axis orientation errors and hence will be a better choice for DTLs. -- Highlights: • An improved permanent magnet quadrupole (PMQ) design with larger good field region is proposed. • We investigate four PMQ designs, including the widely used Halbach and bullet nosed designs. • Analytical calculations are backed by 2D as well as 3D numerical solvers, PANDIRA and RADIA. • The optimized 16 segment rectangular PMQ design is identified to exhibit the largest good field region. • The effect of easy axis orientation

An improved permanent magnet quadrupole design with larger good field region for high intensity proton linacs

International Nuclear Information System (INIS)

Mathew, Jose V.; Rao, S.V.L.S.; Krishnagopal, S.; Singh, P.

2013-01-01

The Low Energy High Intensity Proton Accelerator (LEHIPA), being developed at the Bhabha Atomic Research Centre (BARC) will produce a 20 MeV, 30 mA, continuous wave (CW) proton beam. At these low velocities, space-charge forces dominate, and could lead to larger beam sizes and beam halos. Hence in the design of the focusing lattice of the LEHIPA drift tube linac (DTL) using permanent magnet quadrupoles (PMQs), a larger good field region is preferred. Here we study, using the two dimensional (2D) and three dimensional (3D) simulation codes PANDIRA and RADIA, four different types of cylindrical PMQ designs: 16-segment trapezoidal Halbach configuration, bullet-nosed geometry and 8- and 16-segment rectangular geometries. The trapezoidal Halbach geometry is used in a variety of accelerators since it provides very high field gradients in small bores, while the bullet-nosed geometry, which is a combination of the trapezoidal and rectangular designs, is used in some DTLs. This study shows that a larger good field region is possible in the 16-segment rectangular design as compared to the Halbach and bullet-nosed designs, making it more attractive for high-intensity proton linacs. An improvement in good-field region by ∼16% over the Halbach design is obtained in the optimized 16-segment rectangular design, although the field gradient is lower by ∼20%. Tolerance studies show that the rectangular segment PMQ design is substantially less sensitive to the easy axis orientation errors and hence will be a better choice for DTLs. -- Highlights: • An improved permanent magnet quadrupole (PMQ) design with larger good field region is proposed. • We investigate four PMQ designs, including the widely used Halbach and bullet nosed designs. • Analytical calculations are backed by 2D as well as 3D numerical solvers, PANDIRA and RADIA. • The optimized 16 segment rectangular PMQ design is identified to exhibit the largest good field region. • The effect of easy axis orientation

Rf quadrupole beam dynamics

International Nuclear Information System (INIS)

Stokes, R.H.; Crandall, K.R.; Stovall, J.E.; Swenson, D.A.

1979-01-01

A method has been developed to analyze the beam dynamics of the radiofrequency quadrupole accelerating structure. Calculations show that this structure can accept a dc beam at low velocity, bunch it with high capture efficiency, and accelerate it to a velocity suitable for injection into a drift tube linac

Essay of accelerator R and D in a small laboratory of a university. Prototype of IHQ linac 1985-1989

International Nuclear Information System (INIS)

Hattori, Toshiyuki

2004-01-01

This is a series of stories on developing particle accelerators employing new acceleration principles at a university laboratory. In this paper the design, the cold-model test, the fabrication and the acceleration test of a linear accelerator (linac) of 'IHQ' type are described. The word IHQ is coined by combining 'Inter-digital H' and 'Radio-Frequency Quadrupole', which are the words for types of linacs. The linac of IHQ type can accelerate particles with rather low injection energy and can perform a high acceleration efficiency. In the acceleration test, the proton beam from an RFQ linac with an energy of 0.8MeV was injected to the IHQ linac and accelerated up to 2 MeV as designed. The effective shunt impedance of the accelerator structure was measured to be as high as 132MΩ/m as expected. (K.Y.)

Prototype development of radio frequency cavity and quadrupole for ADSS - initial efforts by mechanical design and prototype development section

International Nuclear Information System (INIS)

Kumar, Manish; Kamble, Sunil; Choughule, L.S.; Kumar, Sunil; Patankar, S.R.; Phalke, V.M.; Dharmik, D.A.; Singh, Tejinder; Ram, Y.; Chaudhari, A.T.; Pathak, Kavindra; Prasad, N.K.; Marathe, V.V.; Matkar, A.W.

2007-01-01

Mechanical Design and Prototype Development Section has participated in the efforts for development of RF cavity and Quadrupole for ADSS. Recently prototype Super conducting RF cavity, Radio Frequency Quadrupole (RFQ), Radio Frequency Quadrupole (RFQ) Simulation Chamber and related experimental setups were developed, fabricated and delivered for the characterisation of various relevant parameters. Under the program for development of Super conducting RF Cavity for high-energy section of LINAC of ADS first prototype RF Cavity of ETP copper was developed by machining and brazing process. The prototype cavity having elliptical and circular profile is the heart of this setup. The cavity is made up of two symmetrical cups joined together by welding or brazing. Various methods are being tried out by MD and PDS for the fabrication of cups and joining them together. Manufacturing of cup by machining and joining them by conventional brazing technique to make the cavity was the first step in this direction. Another method of manufacturing and joining viz forming of cup by deep drawing and joining them by EB welding is in progress. RFQ is a versatile and efficient system for accelerating ion beams especially at low energy. It works in quadrupole mode, which is at 350M Hz. RFQ Focuses, Bunches and Accelerates the beam simultaneously. The bunching is done in this RFQ, which results in more than 95% transmission where as in the normal buncher the transmission is less than 40%. The actual RFQ, which is designed for the PURNIMA facility, will be fabricated from OFHC copper that will accelerate a deuteron (D+) ion beam from 50keV to 400keV over its 1.37meter length. For the validation of manufacturing process and characterisation of various parameters at low frequency a 500mm long prototype RFQ in Aluminium with an accuracy of ± 25microns and surface finish of 1.6 micron has been fabricated by MD and PDS. A simplified simulation chamber to facilitate the development of RFQ for

Design of high-energy high-current linac with focusing by superconducting solenoids

Energy Technology Data Exchange (ETDEWEB)

Batskikh, G.I.; Belugin, V.M.; Bondarev, B.I. [Moscow Radiotechnical Institute (Russian Federation)] [and others

1995-10-01

The advancement of MRTI design for 1.5 GeV and 250 mA ion CW linac was presented in a previous report. In this new linac version all the way from input to output the ions are focused by magnetic fields of superconducting solenoids. The ion limit current is far beyond the needed value. The linac focusing channel offers major advantages over the more conventional ones. The acceptance is 1.7 times as large for such focusing channel as for quadrupole one. Concurrently, a random perturbation sensitivity for such channel is one order of magnitude smaller than in quadrupole channel. These focusing channel features allow to decrease beam matched radius and increase a linac radiation purity without aperture growth. {open_quotes}Regotron{close_quotes} is used as high power generator in linac main part. But D&W cavities need not be divided into sections connected by RF-bridges which denuded them of high coupling factor.

Radio frequency linear accelerators for NDT applications: Basic overview of RF linacs

International Nuclear Information System (INIS)

Hansen, H.J.

1998-01-01

High energy X-ray radiography can be an important part of a quality control program. In this article the author will present an overview of the technology found in a typical high energy X-ray source, the radio frequency (RF) linear accelerator. In NDT, linacs are used primarily for the inspection of thick sections of materials. Linacs are also used in applications such as high energy computed tomography of specimens greater than 1 m thick and cargo container inspection. Recent developments in reliable portable linacs are opening up other applications such as field inspection of pipelines, ships, bridges, and other civil infrastructure. The replacement of isotopes (such as Co-60) by the linac is an area for growth in the future. The shorter exposure times, improved image capabilities, and greatly reduced regulatory requirements of the linac make a persuasive argument for the replacement of isotopes with a portable linac. The linacs discussed here are those with X-ray energies from 1 to 20 MeV intended for use in NDT applications. The discussion will be in very broad terms; it will be impossible to discuss every variation in linac design. In addition, some topics have been necessarily simplified to increase the comprehensibility for a wider audience

Testing begins on Linac4

CERN Multimedia

Katarina Anthony

2012-01-01

On 3 August 2012, the Linac4 radiofrequency quadrupole (RFQ) module was installed at the accelerator test-stand in Building 152. The site will be the module’s home for almost a year, as the linear accelerator enters the assembly and testing stage.   Final module assembly is carried out before installation in Building 152.  Over the next Long Shutdown (LS2), Linac4 will replace the current Linac2 linear accelerator as the first link in CERN’s accelerator chain. It will deliver particles at 160 MeV to the PS Booster, more than triple the energy currently delivered by Linac2. But before the accelerator team can pop the champagne, the various elements of Linac4 will be tested and re-tested in facilities across CERN. “The first Linac4 tests are currently underway, starting with the CERN-built RFQ,” says Carlo Rossi, a physicist in the RF Group of the Beams (BE) Department and the RFQ project coordinator. “It’s an extremely impre...

Low-frequency quadrupole impedance of undulators and wigglers

Directory of Open Access Journals (Sweden)

A. Blednykh

2016-10-01

Full Text Available An analytical expression of the low-frequency quadrupole impedance for undulators and wigglers is derived and benchmarked against beam-based impedance measurements done at the 3 GeV NSLS-II storage ring. The adopted theoretical model, valid for an arbitrary number of electromagnetic layers with parallel geometry, allows to calculate the quadrupole impedance for arbitrary values of the magnetic permeability μ_{r}. In the comparison of the analytical results with the measurements for variable magnet gaps, two limit cases of the permeability have been studied: the case of perfect magnets (μ_{r}→∞, and the case in which the magnets are fully saturated (μ_{r}=1.

First H- beam accelerated at Linac4: 3MeV done, 157 MeV to go!

CERN Multimedia

Linac4 Project Team

2013-01-01

On 14 November, the first H- (one proton surrounded by two electrons) beam was accelerated to the energy of 3 MeV in the Linac4 - the new linear accelerator that will replace Linac2 as low-energy injector in the LHC accelerator chain.      A view of the Linac4 taken during the recent tests (top image) and the current measured by the instruments at the end of the acceleration line on 14 November (bottom image). Images: Linac4 collaboration. Using the recently installed Radio Frequency Quadrupole (RFQ) accelerator, 13 mA of current were accelerated to the energy of 3 MeV. After the successful commissioning of the Linac4 RFQ at the 3 MeV test stand completed during the first months of 2013, the whole equipment (composed of the RFQ itself, the following Medium Energy Beam Transport line and its diagnostic line) were moved to the Linac4 tunnel during summer and installed in their final position. In the meantime, a new ion source was assembled, installed and successfu...

Preliminary design study and problem definition for intense CW superconducting deuteron ion linac for fusion material study

International Nuclear Information System (INIS)

Tanabe, Y.; Kakutani, N.; Ota, T.; Yamaguchi, A.; Takeda, O.; Wachi, Y.; Yamazaki, C.; Morii, Y.

1997-01-01

The advantages of superconducting (SC) cavity have been verified for many electron accelerators and the application of SC cavity to high intensity CW ion linacs is currently being considered. These linacs have been required for neutron irradiation tests of materials, transmutation of nuclear waste and so on. An SC linac consisting of SC cavities, SC quadrupole magnets and cryostats, was preliminarily designed to investigate the feasibility of applying to deuteron machine. Beam dynamics analysis was also carried out by using a modified PARMILA code in order to confirm no beam loss. Since radiation damage of superconductors is especially severe for such a machine, data relating to the damage were surveyed and discussed. Moreover, other major facilities such as cryogenic system, radio frequency amplifier and RF control system were considered. Many problems to be solved were defined but no critical issues were found. In consequence, it became clear that SC linac is very attractive and competitive with a room-temperature linac. (orig.)

Beam dynamics and commissioning of low and medium energy H- beam at Linac4

CERN Document Server

Satri, Masoomeh Yarmohammadi; Lombardi, Alessandra; Lamehi-Rachti , Mohammad

The First step of the CERN Large Hadron Collider injectors upgrade (LIU) project is Linac4. It accelerates H- ions to 160 MeV in an 80 m long accelerator housed in a tunnel 12 m underground, presently under construction. It will replace the present 50 MeV proton Linac2 as injector of the proton accelerator complex to increase the LHC luminosity. It consists of a 45 keV RF volume source, a twosolenoid Low Energy Beam Transport (LEBT), a 352.2 MHz Radio Frequency Quadrupole (RFQ) accelerating the beam to 3 MeV, a Medium Energy Beam Transport (MEBT) line. The MEBT houses a fast chopper to selectively remove unwanted micro-bunches in the 352 MHz sequence and avoid losses at capture in the CERN PSB (1 MHz). After chopping, the beam acceleration continues by a 50 MeV Drift Tube Linac (DTL), a 100 MeV Cell-Coupled Drift Tube Linac and a Pi-Mode Structure bringing the beam to the final energy of 160 MeV. Linac4 has been commissioned with a temporary source up to 12 MeV. The beam commissioning stages of Linac4 in LEBT...

The Superconducting Super Collider (SSC) linac

International Nuclear Information System (INIS)

Watson, J.M.

1990-09-01

The preliminary design of the 600 MeV H - linac for the Superconducting Super Collider injector is described. The linac must provide a 25 mA beam during 7--35 μs macropulses at Hz within injection bursts. Normalized transverse emittances of less than 0.5 π mm-mrad (rms) are required for injection into the Low Energy Booster synchrotron. Cost, ease of commissioning, and operational reliability are important considerations. The linac will consists of an H - source with electrostatic LEBT, 2.5 MeV radiofrequency quadrupole accelerator, a 70 MeV drift-tube linac, and 530 MeV and the side-coupled linac operates at 1284 MHz. A modest total length of 150 m results from the tradeoff between cost optimization and reliability. The expected performance from beam dynamics simulations and the status of the project are described. 11 refs., 1 fig., 6 tabs

1974 view into the cage of the 520 keV electrostatic preaccelerator of Linac 1

CERN Multimedia

1974-01-01

The condenser of the high voltage circuit (column in the foreground) is being serviced by Jean Luc Vallet. Standing on the electronics platform (the big, open metallic structure on insulating pillars, for details see 7403120) is Bob Nettelton. The column at the right edge of the photo is part of the bouncer (see also 7403066X) which compensated the voltage drop during acceleration of a proton pulse. In the background is the source (open pill box structure) attached to the accelerating column, barely visible) behind. The "old" 50 MeV Linac 1, the original PS injector built in the 1950s, was (since 1976) replaced by a new 50 MeV linac (Linac 2) with a 750 keV "Cockcroft-Walton" pre-injector(see 7602012X), later replaced by a 750 keV Radio Frequency Quadrupole (RFQ) preaccelerator. Linac 1 co-existed until mid 1992 (from 1982 onwards it was mainly used to inject "test-particles" into the Low Energy Antiproton ring LEAR). In 1984 the electrostatic preaccelerator of linac 1 was replaced by a 520 keV RFQ ( 8303511X...

Design study of a radio-frequency quadrupole for high-intensity beams

Science.gov (United States)

Bahng, Jungbae; Kim, Eun-San; Choi, Bong-Hyuk

2017-07-01

The Rare isotope Accelerator Of Newness (RAON) heavy-ion accelerator has been designed for the Rare Isotope Science Project (RISP) in Korea. The RAON will produce heavy-ion beams from 660-MeV-proton to 200-MeV/u-uranium with continuous wave (CW) power of 400 kW to support research in various scientific fields. Its system consists of an ECR ion source, LEBTs with 10 keV/u, CW RFQ accelerator with 81.25 MHz and 500 keV/u, a MEBT system, and a SC linac. In detail, the driver linac system consists of a Quarter Wave Resonator (QWR) section with 81.25 MHz and a Half Wave Resonator (HWR) section with 162.5 MHz, Linac-1, and a Spoke Cavity section with 325 MHz, Linac-2. These linacs have been designed to optimize the beam parameters to meet the required design goals. At the same time, a light-heavy ion accelerator with high-intensity beam, such as proton, deuteron, and helium beams, is required for experiments. In this paper, we present the design study of the high intensity RFQ for a deuteron beam with energies from 30 keV/u to 1.5 MeV/u and currents in the mA range. This system is composed of an Penning Ionization Gauge ion source, short LEBT with a RF deflector, and shared SC Linac. In order to increase acceleration efficiency in a short length with low cost, the 2nd harmonic of 162.5 MHz is applied as the operation frequency in the D+ RFQ design. The D+ RFQ is designed with 4.97 m, 1.52 bravery factor. Since it operates with 2nd harmonic frequency, the beam should be 50% of the duty factor while the cavity should be operated in CW mode, to protect the downstream linac system. We focus on avoiding emittance growth by the space-charge effect and optimizing the RFQ to achieve a high transmission and low emittance growth. Both the RFQ beam dynamics study and RFQ cavity design study for two and three dimensions will be discussed. Supported by Korea University Future Research Grant

Linac4: the final assembly stage is under way

CERN Multimedia

CERN Bulletin

2013-01-01

The Linac4 radiofrequency quadrupole (RFQ) module was installed at the accelerator test-stand in Building 152 last August. After an assembly phase and tests that concluded last March with the acceleration of a hydrogen beam to 3 MeV, the module has just been permanently installed in the new Linac4 tunnel (Building 400). The installation of the MEBT (Medium Energy Beam Transport) will begin shortly, followed by the start of the first Linac4 commissioning phase.     To find out more about the Linac4 RFQ module, read the previous Bulletin articles published in Nos. 21-22/2010 and 35-36/2012.

Software of the System Protection for the PEFP 20MeV Proton Linac

International Nuclear Information System (INIS)

Song, Young-Gi; Hong, In-Seok; Cho, Yong-Sub

2007-01-01

A 20 MeV proton linear accelerator (linac) has been developed at Proton Engineering Frontier Project (PEFP). A 20 MeV linac consists of 50 keV proton injector, 3 MeV radio frequency quadrupole (RFQ), and 20 MeV drift tube linac (DTL). PEFP control system is developed with several sub-systems (e.g. machine control, diagnostic control, timing control, and interlock systems). These systems have each EPICS based control system which provides a network-based real time distributed control. For stable and harmonic operation, we had developed sequential logic by using state notation language (SNL) and database records with alarm fields for warning signal. The various control system can drop a transmission rate of the control network traffic. We need to manage control signals by a control network gateway and protect values of control servers by security management. In this paper, the stabilization methods of the control signals are described and the results of the stabilized signals are presented

Development of the Medium Energy Linac Systems

International Nuclear Information System (INIS)

Jang, Ji Ho; Kwon, Hyeok Jung; Kim, Dae Il; Kim, Han Sung; Park, Bum Sik; Seol, Kyung Tae; Song, Young Gi; Yun, Sang Pil; Cho, Yong Sub; Hong, In Seok

2008-05-01

The main purpose of this project is developing 100-MeV proton linear accelerator (linac) for proton engineering frontier project (PEFP). In the first phase of the PEFP, the development of the 20-MeV linac has successfully finished. Hence the work scope of this project is designing the linac to accelerate proton beams from 20-MeV up to 100-MeV, fabricating the linac up to 45 MeV, fabricating one set of the medium energy beam transport (MEBT) tank, and developing the low level radio frequency (LLRF) system and the control system. The basic role of the new proton accelerator is accelerating 20-mA proton beams from 20 MeV up to 100 MeV. The first step of the design procedure is optimizing and determining the accelerator parameters. The beam loss is also main concern in the design stage. The drift tube (DT) and the quadrupole magnets are designed to be optimized to the new linac design. The other purpose is confirming the new design by fabricating and tuning the drift tube linac (DTL). The 20MeV proton beam divided into two directions. One is supplying the beams to user group by turning on the 45-degree bending magnet. The other is guided into the 100-MeV DTL by tuning off the dipole magnet. That is why the PEFP MEBT located after 20-MeV DTL. The MEBT is realized as two small DTL tanks with three cells and a 45-degree bending magnet. The fabrication of one MEBT tank is another purpose of this project. The other purposes of this project is developing the LLRF system to control the RF signal and control system to monitor and control the vacuum system, magnet power supply, etc

PIC Simulations in Low Energy Part of PIP-II Proton Linac

Energy Technology Data Exchange (ETDEWEB)

Romanov, Gennady

2014-07-01

The front end of PIP-II linac is composed of a 30 keV ion source, low energy beam transport line (LEBT), 2.1 MeV radio frequency quadrupole (RFQ), and medium energy beam transport line (MEBT). This configuration is currently being assembled at Fermilab to support a complete systems test. The front end represents the primary technical risk with PIP-II, and so this step will validate the concept and demonstrate that the hardware can meet the specified requirements. SC accelerating cavities right after MEBT require high quality and well defined beam after RFQ to avoid excessive particle losses. In this paper we will present recent progress of beam dynamic study, using CST PIC simulation code, to investigate partial neutralization effect in LEBT, halo and tail formation in RFQ, total emittance growth and beam losses along low energy part of the linac.

Radio-frequency quadrupole, RFQ-1

CERN Multimedia

Photographic Service

1983-01-01

Inner structure of RFQ-1, which replaced in 1983 the Cockcroft-Walton preinjector of Linac 1. It accelerated protons and negative hydrogen ions to 520 keV during the period that Linac 1 was used for LEAR (1981-1996). The precision-machined modulated electrodes ("vanes") are shaped to first bunch the dc-beam from the ion source and then provide simultaneous acceleration and focusing of the beam.

Beam-based alignment technique for the SLC [Stanford Linear Collider] linac

International Nuclear Information System (INIS)

Adolphsen, C.E.; Lavine, T.L.; Atwood, W.B.

1989-03-01

Misalignment of quadrupole magnets and beam position monitors (BPMs) in the linac of the SLAC Linear Collider (SLC) cause the electron and positron beams to be steered off-center in the disk-loaded waveguide accelerator structures. Off-center beams produce wakefields which limit the SLC performance at high beam intensities by causing emittance growth. Here, we present a general method for simultaneously determining quadrupole magnet and BPM offsets using beam trajectory measurements. Results from the application of the method to the SLC linac are described. The alignment precision achieved is approximately 100 μm, which is significantly better than that obtained using optical surveying techniques. 2 refs., 4 figs

Radio-frequency quadrupole linear accelerator

International Nuclear Information System (INIS)

Wangler, T.P.; Stokes, R.H.

1980-01-01

The radio-frequency quadrupole (RFQ) is a new linear accelerator concept in which rf electric fields are used to focus, bunch, and accelerate the beam. Because the RFQ can provide strong focusing at low velocities, it can capture a high-current dc ion beam from a low-voltage source and accelerate it to an energy of 1 MeV/nucleon within a distance of a few meters. A recent experimental test at the Los Alamos Scientific Laboratory (LASL) has confirmed the expected performance of this structure and has stimulated interest in a wide variety of applications. The general properties of the RFQ are reviewed and examples of applications of this new accelerator are presented

Drift tube with an electro-quadrupole magnet made with a conventional enamel wire for the proton engineering frontier project drift tube linac

Science.gov (United States)

Kim, Y. H.; Kwon, H. J.; Cho, Y. S.

2006-12-01

The proton engineering frontier project (PEFP) drift tube linac (DTL) chose the new type of electro-quadrupole magnet (EQM) using an enameled wire for a drift tube. By using this kind of EQM, we could simplify the drift tube structure. We verified the structural stability and thermal stability of this drift tube structure through a computational analysis and a simple experiment. We also verified the stability of the enameled wire regarding corrosion through a long period test of about 1 year. It was concluded that the design and fabrication of the drift tube and the EQM were successful.

Drift tube with an electro-quadrupole magnet made with a conventional enamel wire for the proton engineering frontier project drift tube linac

Energy Technology Data Exchange (ETDEWEB)

Kim, Y.H. [PEFP, KAERI, DaeJeon (Korea, Republic of)]. E-mail: yhkim72@kaeri.re.kr; Kwon, H.J. [PEFP, KAERI, DaeJeon (Korea, Republic of); Cho, Y.S. [PEFP, KAERI, DaeJeon (Korea, Republic of)

2006-12-21

The proton engineering frontier project (PEFP) drift tube linac (DTL) chose the new type of electro-quadrupole magnet (EQM) using an enameled wire for a drift tube. By using this kind of EQM, we could simplify the drift tube structure. We verified the structural stability and thermal stability of this drift tube structure through a computational analysis and a simple experiment. We also verified the stability of the enameled wire regarding corrosion through a long period test of about 1 year. It was concluded that the design and fabrication of the drift tube and the EQM were successful.

Drift tube with an electro-quadrupole magnet made with a conventional enamel wire for the proton engineering frontier project drift tube linac

International Nuclear Information System (INIS)

Kim, Y.H.; Kwon, H.J.; Cho, Y.S.

2006-01-01

The proton engineering frontier project (PEFP) drift tube linac (DTL) chose the new type of electro-quadrupole magnet (EQM) using an enameled wire for a drift tube. By using this kind of EQM, we could simplify the drift tube structure. We verified the structural stability and thermal stability of this drift tube structure through a computational analysis and a simple experiment. We also verified the stability of the enameled wire regarding corrosion through a long period test of about 1 year. It was concluded that the design and fabrication of the drift tube and the EQM were successful

Range of Possible Beam Current in Linac4

CERN Document Server

Lallement, J-B; CERN. Geneva. BE Department

2009-01-01

Linac4 is a new accelerator under construction at CERN. It is designed to accelerate H- ions to 160MeV, for injection into the existing Proton Synchrotron Booster (PSB). It is also the front-end of the SPL Linac, a high energy proton driver that will reach the energy of 5GeV. The Linac baseline design has been done for a nominal beam peak current of 70mA but it will certainly have to deal with different currents. 132 out of 155 quadrupoles in the Linac are permanent magnets, this choice of using PMQ having fixed gradient, mainly in the DTL and in the CCDTL may then entail issues concerning the beam transverse matching and quality from current different from the nominal one. In this paper, we present the beam dynamics performances in Linac4 obtained for different currents.

First muon acceleration using a radio-frequency accelerator

Directory of Open Access Journals (Sweden)

S. Bae

2018-05-01

Full Text Available Muons have been accelerated by using a radio-frequency accelerator for the first time. Negative muonium atoms (Mu^{-}, which are bound states of positive muons (μ^{+} and two electrons, are generated from μ^{+}’s through the electron capture process in an aluminum degrader. The generated Mu^{-}’s are initially electrostatically accelerated and injected into a radio-frequency quadrupole linac (RFQ. In the RFQ, the Mu^{-}’s are accelerated to 89 keV. The accelerated Mu^{-}’s are identified by momentum measurement and time of flight. This compact muon linac opens the door to various muon accelerator applications including particle physics measurements and the construction of a transmission muon microscope.

Laced permanent magnet quadrupole drift tube magnets

International Nuclear Information System (INIS)

Feinberg, B.; Behrsing, G.U.; Halbach, K.; Marks, J.S.; Morrison, M.E.; Nelson, D.H.

1988-10-01

A laced permanent magnet quadrupole drift tube magnet has been constructed for a proof-of-principle test. The magnet is a conventional tape-wound quadrupole electromagnet, using iron pole- pieces, with the addition of permanent magnet material (neodymium iron) between the poles to reduce the effects of saturation. The iron is preloaded with magnetic flux generated by the permanent magnet material, resulting in an asymmetrical saturation curve. Since the polarity of the quadrupole magnets in a drift tube linac is not reversed we can take advantage of this asymmetrical saturation to provide greater focusing strength. The magnet configuration has been optimized and the vanadium permendur poles needed in a conventional quadrupole have been replaced with iron poles. The use of permanent magnet material has allowed us to increase the focusing strength of the magnet by about 20% over that of a conventional tape-wound quadrupole. Comparisons will be made between this magnet and the conventional tape-wound quadrupole. 3 refs., 5 figs

MEQALAC: (multiple electrostatic quadrupole linac): a new approach to low beta rf acceleration

International Nuclear Information System (INIS)

Mobley, R.M.; Brodowski, J.J.; Gammel, G.M.; Keane, J.T.; Maschka, A.W.; Sanders, R.T.

1980-01-01

MEQALAC is an acronym for a multiple-beam electrostatic-quadrupole array linear accelerator. The principle of operation is very simple. It makes use of the fact that electrostatic quadrupoles focus more effectively at low velocities than conventional magnetic quadrupoles. Moreover, the pole-tip field of an electrostatic quadrupole is limited by field emission of electrons, and is not a function of the size of the quadrupole. Conventional magnetic quadrupoles, on the other hand, require increasingly high current densities if one attempts to scale to smaller size

The Linac4 DTL Prototype: Low and High Power Measurements

CERN Document Server

De Michele, G; Marques-Balula, J; Ramberger, S

2012-01-01

The prototype of the Linac4 Drift Tube Linac (DTL) has undergone low power measurements in order to verify the RF coupling and to adjust the post-coupler lengths based on bead-pull and spectrum measurements. Following the installation at the test stand, the cavity has been subjected to high power operation at Linac4 and SPL duty cycles. Saturation effects and multipacting have been observed and linked to X-ray emission. Voltage holding is reported in the presence of magnetic fields from permanent magnet quadrupoles (PMQ) installed in the first drift tubes.

Space charge compensation on the low energy beam transport of Linac4

CERN Document Server

AUTHOR|(SzGeCERN)733270; Scrivens, Richard; Jesus Castillo, Santos

Part of the upgrade program in the injector chains of the CERN accelerator complex is the replacement of the the proton accelerator Linac2 for the brand new Linac4 which will accelerate H$^-$ and its main goal is to increase the beam intensity in the next sections of the LHC accelerator chain. The Linac4 is now under commissioning and will use several ion sources to produce high intensity unbunched H$^-$ beams with different properties, and the low energy beam transport (LEBT) is the system in charge of match all these different beams to the Radio frequency quadrupole (RFQ). The space charge forces that spread the beam ions apart of each other and cause emittance growth limits the maximum intensity that can be transported in the LEBT, but the space charge of intense unbunched ion beams can be compensated by the generated ions by the impact ionization of the residual gas, which creates a source of secondary particles inside the beam pipe. For negative ion beams, the effect of the beam electric field is to ex...

Mutual compensation of wakefield and chromatic effects of intense linac bunches

International Nuclear Information System (INIS)

Seeman, J.T.; Merminga, N.

1990-05-01

Mutual compensation of transverse and chromatic effects for intense electron bunches in a high-energy linac is a recent Novosibirsk idea which provides a new control of emittance enlargement. In this paper we elaborate on the principles and constraints for this new technique which requires careful matching of internal bunch parameters with external forces. With species values of the bunch length, bunch intensity, and klystron phasing, the transverse-wakefield-induced forces within the bunch can be cancelled by energy-dependent forces from the quadrupole lattice at all positions along the linac. Under these conditions the tolerances for quadrupole alignment, dipole stability, and injection launch errors are significantly relaxed. 7 refs., 8 figs

Assembly and RF Tuning of the Linac4 RFQ at CERN

CERN Document Server

Rossi, C; Hansen, J; Lallement, JB; Lombardi, AM; Pugnat, D; Vandoni, G; Timmins, M; Vretenar, M; Mathot, S; Piquet, O; Novo, J; Le Noa, Y; France, A; Desmons, M

2013-01-01

The fabrication of Linac4 is progressing at CERN with the goal of making a 160 MeV H- beam available to the LHC injection chain as from 2015. In the Linac4 the first stage of beam acceleration, after its extraction from the ion source, is provided by a Radiofrequency Quadrupole accelerator (RFQ), operating at the RF frequency of 352.2 MHz and which accelerates the ion beam to the energy of 3 MeV. The RFQ, made of three modules, one meter each, is of the four-vane kind, has been designed in the frame of a collaboration between CERN and CEA and has been completely machined and assembled at CERN. The paper describes the assembly of the RFQ structure and reports the results of RF low power measurements, in order to achieve the required accelerating field flatness within 1% of the nominal field profile.

Radio-frequency quadrupole, RFQ-1

CERN Multimedia

CERN PhotoLab

1983-01-01

Inner structure of RFQ-1, which in 1984 replaced the Cockcroft-Walton preinjector of Linac 1. It accelerated protons and negative hydrogen-ions to 520 keV during the period that Linac 1 was used for LEAR (1981-1996). The precision-machined modulated electrodes ("vanes") are shaped to first bunch the dc-beam from the ion source and then provide simultaneous acceleration and focusing of the beam. See also 8303511. For pictures of pre-installation RF tests, see 8202557, 8202558, 8202559.

A heavy ion linac complex for RI beams

International Nuclear Information System (INIS)

Arai, Shigeaki

1995-01-01

A heavy ion linac complex for RI-beams has been under construction since fiscal year 1992 at INS. The linac complex comprises following accelerating structures: a 25.5-MHz split coaxial RFQ (SCRFQ), a 51-MHz interdigital-H (IH) linac, and a 25.5-MHz rebuncher cavity. The SCRFQ with modulated vanes accelerates ions with a charge-to-mass ratio (q/A) greater than 1/30 from 2 to 170 keV/u. The IH linac comprises four cavities and three magnetic quadrupole triplets placed between cavities, accelerates ions with q/A≥1/10, and varies the output energy continuously in the range 0.17 ∼1.05 MeV/u. The rebuncher cavity with six accelerating gaps is a double coaxial λ/4 resonator, and the total accelerating voltage is 200 kV. (author)

Variable-field permanent-magnet quadrupole for the SSC

International Nuclear Information System (INIS)

Barlow, D.B.; Kraus, R.H. Jr.; Martinez, R.P.; Meyer, R.E.

1994-01-01

A set of compact variable-field permanent-magnet quadrupoles have been designed, fabricated, and tested for use in the SSC linac matching section. The quadrupoles have 24 mm-diameter apertures and 40 mm-long poles. The hybrid (permanent-magnet and iron) design, uses a fixed core of magnet material (NdFeB) and iron (C-1006) surrounded by a rotating ring of the same magnet material and iron. The quadrupole gradient-length product can be smoothly varied from a minimum of 0.7 T up to a maximum of 4.3 T by a 90 degree rotation of the outer ring of iron and magnet material

Variable-field permanent magnet quadrupole for the SSC

International Nuclear Information System (INIS)

Barlow, D.B.; Kraus, R.H. Jr.; Martinez, R.P.; Meyer, R.E.

1993-01-01

A set of compact variable-field permanent-magnet quadrupoles have been designed, fabricated, and tested for use In the SSC linac matching section. The quadrupoles have 24 mm-diameter apertures and 40 mm-long poles. The hybrid (permanent-magnet and iron) design, uses a fixed core of magnet material (NdFeB) and iron (C-1006) surrounded by a rotating ring of the same magnet material and iron. The quadrupole gradient-length product can be smoothly varied from a minimum of 0.7 T up to a maximum, of 4.3 T by a 90 degrees rotation of the outer ring of iron and magnet material

Approach of a failure analysis for the MYRRHA linac

International Nuclear Information System (INIS)

Carneiro, J.P.; Medeiros-Romao, L.; Salemne, R.; Vandeplassche, D.; Biarotte, J.L.; Bouly, F.; Uriot, D.

2015-01-01

The MYRRHA project currently under development at SCK-CEN (Mol, Belgium) is a subcritical research reactor that requires a 600 MeV proton accelerator as a driver. This linac is expected to produce a beam power of 1.5 MW onto a spallation target for the reactor to deliver a thermal power around 70 MW. Thermomechanical considerations of the spallation target set stringent requirements on the beam trip rate which should not exceed 40 trips/year for interruptions longer than three seconds. The 3 underlying principles in the design of the MYRRHA linac are elements redundancy (like the dual-injector), elements operation at de-rated values (like cavities operating at about 30% from their nominal operating points) and the fault tolerance concept, which allows the failure of a beamline component to be compensated by its neighbouring elements. Studies presented in this document show that in the event of a failure of the first cryo-module or the first quadrupole doublet the linac can resume nominal operation with a re-matched lattice. Since the fault tolerance procedure is expected to work more efficiently at higher energies (due to lower space charge effects) we can extrapolate from our studies that the MYRRHA linac is expected to operate with the failure of any cryo-module or quadrupole doublet in the main linac. A virtual accelerator-based control system is mandatory for the operation of the MYRRHA linac to ensure the very fast implementation (<3 seconds) of the fault tolerance procedure. The virtual accelerator uses a beam dynamics code (like TRACEWIN or TRACK) to compute the model of the real accelerator in operation and interacts with this later through the accelerator control command

Alignment and Field Error Tolerance in Linac4

CERN Document Server

Bellodi, G; Garcia Tudela, M; Hein, L; Lallement, J B; Lanzone, S; Lombardi, A M; Posocco, P; Sargsyan, E

2011-01-01

LINAC4 [1] is a linear accelerator for negative Hydrogen ions (H−), which will replace the 50 MeV proton LINAC (LINAC2) as linear injector for the CERN accelerators. The higher output energy (160 MeV) together with charge-exchange injection will allow increasing beam intensity in the following machines. LINAC4 is about 80 m long, normal-conducting, and will be housed in a tunnel 12 m below ground on the CERN Meyrin site. The location has been chosen to allow using LINAC4 as the first stage of acceleration for a Multi-MegaWatt superconducting LINAC (SPL [2]). A 60 m long transfer line brings the beam towards the present LINAC2-to-PS Booster transfer line, which is joined at the position of BHZ20. The new transfer line consists of 17 new quadrupoles, an RF cavity and 4 bending magnets to adjust both the direction and the level for injection into the PS Booster. End-to-end beam dynamics simulations have been carried out in parallel with the codes PATH [3] and TRACEWIN[4]. Following the definition of the layout...

Comparison of conventional and novel quadrupole drift tube magnets inspired by Klaus Halbach

Energy Technology Data Exchange (ETDEWEB)

Feinberg, B. [Lawrence Berkeley Lab., CA (United States)

1995-02-01

Quadrupole drift tube magnets for a heavy-ion linac provide a demanding application of magnet technology. A comparison is made of three different solutions to the problem of providing an adjustable high-field-strength quadrupole magnet in a small volume. A conventional tape-wound electromagnet quadrupole magnet (conventional) is compared with an adjustable permanent-magnet/iron quadrupole magnet (hybrid) and a laced permanent-magnet/iron/electromagnet (laced). Data is presented from magnets constructed for the SuperHILAC heavy-ion linear accelerator, and conclusions are drawn for various applications.

Low-frequency nuclear quadrupole resonance with a dc SQUID

International Nuclear Information System (INIS)

Chang, J.W.

1991-07-01

Conventional pure nuclear quadrupole resonance (NQR) is a technique well suited for the study of very large quadrupolar interactions. Numerous nuclear magnetic resonance (NMR) techniques have been developed for the study of smaller quadrupolar interactions. However, there are many nuclei which have quadrupolar interactions of intermediate strength. Quadrupolar interactions in this region have traditionally been difficult or unfeasible to detect. This work describes the development and application of a SQUID NQR technique which is capable of measuring intermediate strength quadrupolar interactions, in the range of a few hundred kilohertz to several megahertz. In this technique, a dc SQUID (Superconducting QUantum Interference Device) is used to monitor the longitudinal sample magnetization, as opposed to the transverse magnetization, as a rf field is swept in frequency. This allows the detection of low-frequency nuclear quadrupole resonances over a very wide frequency range with high sensitivity. The theory of this NQR technique is discussed and a description of the dc SQUID system is given. In the following chapters, the spectrometer is discussed along with its application to the study of samples containing half-odd-integer spin quadrupolar nuclei, in particular boron-11 and aluminum-27. The feasibility of applying this NQR technique in the study of samples containing integer spin nuclei is discussed in the last chapter. 140 refs., 46 figs., 6 tabs

Mechanical considerations in cw linacs

International Nuclear Information System (INIS)

King, J.D.

1985-01-01

An 80-MHz radio-frequency quadrupole (RFQ) linac has been designed, fabricated and operated at 100% duty factor (cw) for the Fusion Materials Irradiation Test (FMIT) project at Los Alamos. This paper describes the design features, fabrication techniques, and operational problems of the device. The RFQ is an assembly of heavy steel, copper-plated weldments. It measures about 15 ft (4.5 m) long by 5 ft (1.5 m) in diameter and weighs over 12 t. Major components are two pair of diametrically orthogonal vanes mounted in a core cylinder. The core is assembled into a manifold cylinder that couples rf power into the vane quadrants. The design features discussed include assembly of hollow wall, flood-cooled components; high-conductivity rf seals; removable and adjustable vanes; and tuning devices. Fabrication challenges such as close-tolerance weldments, vane-tip-contour machining and large-component plating requirements are covered

Preliminary Analysis on Linac Oscillation Data LI05-19 and Wake Field Energy Loss in FACET Commissioning 2012

Energy Technology Data Exchange (ETDEWEB)

Sun, Yipeng; /SLAC

2012-07-23

In this note, preliminary analysis on linac ocsillation data in FACET linac LI05-09 plus LI11-19 is presented. Several quadrupoles are identified to possibly have different strength, compared with their designed strength in the MAD optics model. The beam energy loss due to longitudinal wake fields in the S-band linac is also analytically calculated, also by LITRACK numerical simulations.

Magnetic Measurement Results of the LCLS Undulator Quadrupoles

Energy Technology Data Exchange (ETDEWEB)

Anderson, Scott; Caban, Keith; Nuhn, Heinz-Dieter; Reese, Ed; Wolf, Zachary; /SLAC

2011-08-18

This note details the magnetic measurements and the magnetic center fiducializations that were performed on all of the thirty-six LCLS undulator quadrupoles. Temperature rise, standardization reproducibility, vacuum chamber effects and magnetic center reproducibility measurements are also presented. The Linac Coherent Light Source (LCLS) undulator beam line has 33 girders, each with a LCLS undulator quadrupole which focuses and steers the beam through the beam line. Each quadrupole has main quadrupole coils, as well as separate horizontal and vertical trim coils. Thirty-six quadrupoles, thirty-three installed and three spares were, manufactured for the LCLS undulator system and all were measured to confirm that they met requirement specifications for integrated gradient, harmonics and for magnetic center shifts after current changes. The horizontal and vertical dipole trims of each quadrupole were similarly characterized. Each quadrupole was also fiducialized to its magnetic center. All characterizing measurements on the undulator quads were performed with their mirror plates on and after a standardization of three cycles from -6 to +6 to -6 amps. Since the undulator quadrupoles could be used as a focusing or defocusing magnet depending on their location, all quadrupoles were characterized as focusing and as defocusing quadrupoles. A subset of the undulator quadrupoles were used to verify that the undulator quadrupole design met specifications for temperature rise, standardization reproducibility and magnetic center reproducibility after splitting. The effects of the mirror plates on the undulator quadrupoles were also measured.

Scheme to funnel ion beams with a radio-frequency quadrupole

International Nuclear Information System (INIS)

Stokes, R.H.; Minerbo, G.N.

1985-01-01

We describe a proposed method to funnel ion beams using a new form of the radio-frequency quadrupole (RFQ) structure. This RFQ accepts two bunched ion beams and combines them into a single final beam with interlaced microstructure pulses. It also provides uninterrupted periodic transverse focusing to facilitate the funneling of beams with high current and low emittance

Frequency to digital converter for IUAC Linac control system

International Nuclear Information System (INIS)

Jain, Mamta; Subramaiam, E.T.; Sahu, B.K.

2015-01-01

A frequency to digital converter CAMAC module has been designed and developed for LINAC control systems. This module is used to see the frequency difference of master clock and the resonator frequency digitally without using the oscilloscope. Later on this can be used for automatic tuning and locking of the cavities using piezoelectric actuator based tunner control. This module has eight independent channels to fulfill the need of all the eight cavities of the cryostat. A Schmitt trigger along with level converaccepts almost any form of pulse train, with 30 Vp-p. The time period is measured by counters clocked from a high resolution clock (10 MHz +/- 250 ps). The counter values are cross checked at both the input levels. Frequency is obtained from the computed time period by a special divisor core implemented inside the FPGA. The major task was the implementation of eight individual divisor cores and routing inside one Spartan 3s500E FPGA chip

A Study of Failure Modes in the ILC Main Linac

CERN Document Server

Eliasson, Peder; Krücker, Dirk; Latina, Andrea; Poirier, Freddy; Schulte, Daniel; Walker, Nicholas John; Xia, Guoxing

2006-01-01

Failures in the ILC can lead to beam loss or even damage the machine. In the paper quadrupole failures and errors in the klystron phase are being investigated and the impact on the machine protection is being considered for the main linac.

LINAC4 low energy beam measurements

CERN Document Server

Hein, L M; Lallement, J B; Lombardi, A M; Midttun, O; Posocco, P; Scrivens, R

2012-01-01

Linac4 is a 160 MeV normal-conducting linear accelerator for negative Hydrogen ions (H−), which will replace the 50 MeV proton Linac (Linac2) as linear injector for the CERN accelerators. The low energy part, comprising a 45 keV Low Energy Beam Transport system (LEBT), a 3 MeV Radiofrequency Quadrupole (RFQ) and a Medium Energy Beam Transport (MEBT) is being assembled in a dedicated test stand for pre-commissioning with a proton beam. During 2011 extensive measurements were done after the source and after the LEBT with the aim of preparing the RFQ commissioning and validating the simulation tools, indispensable for future source upgrades. The measurements have been thoroughly simulated with a multi-particle code, including 2D magnetic field maps, error studies, steering studies and the generation of beam distribution from measurements. Emittance, acceptance and transmission measurements will be presented and compared to the results of the simulations.

CERN Linac4 - The Space Charge Challenge Design and Commission

CERN Document Server

Hein, Lutz Matthias; Holzer, Bernhard

In the first phase of the upgrade program of the CERN accelerator complex the proton injector Linac2 will be replaced by a new, normal-conducting $H^-$ ion Linac, Linac4, allowing a significant increase of the proton flux intensity along the downstream accelerator complex. In the design of Linac4 three beam transport sections are implemented to match the beam between the different accelerator elements and to model the longitudinal pulse structure. These three beam transport sections, which are the most critical locations in terms of beam quality preservation, are in the focus of this thesis. During the work of this thesis the low energy beam transport (LEBT), which is required to match the source beam to the radiofrequency quadrupole (RFQ), has been commissioned and its beam dynamics re-constructed. The measurement campaign used to re-construct the LEBT beam dynamics was performed with the aim to prepare the RFQ commissioning and to maximise the LEBT performance. Downstream of the Linac4 accelerator the beam...

High gradient linac for proton therapy

Directory of Open Access Journals (Sweden)

S. Benedetti

2017-04-01

Full Text Available Proposed for the first time almost 30 years ago, the research on radio frequency linacs for hadron therapy experienced a sparkling interest in the past decade. The different projects found a common ground on a relatively high rf operating frequency of 3 GHz, taking advantage of the availability of affordable and reliable commercial klystrons at this frequency. This article presents for the first time the design of a proton therapy linac, called TULIP all-linac, from the source up to 230 MeV. In the first part, we will review the rationale of linacs for hadron therapy. We then divided this paper in two main sections: first, we will discuss the rf design of the different accelerating structures that compose TULIP; second, we will present the beam dynamics design of the different linac sections.

Effect of dipole-quadrupole Robinson mode coupling upon the beam response to radio-frequency phase noise

Directory of Open Access Journals (Sweden)

R. A. Bosch

2006-09-01

Full Text Available In an electron storage ring, coupling between dipole and quadrupole Robinson oscillations modifies the spectrum of longitudinal beam oscillations driven by radio-frequency (rf generator phase noise. In addition to the main peak at the resonant frequency of the coupled dipole Robinson mode, another peak occurs at the resonant frequency of the coupled quadrupole mode. To describe these peaks analytically for a quadratic synchrotron potential, we include the dipole and quadrupole modes when calculating the beam response to generator noise. We thereby obtain the transfer function from generator-noise phase modulation to beam phase modulation with and without phase feedback. For Robinson-stable bunches confined in a synchrotron potential with a single minimum, the calculated transfer function agrees with measurements at the Aladdin 800-MeV electron storage ring. The transfer function is useful in evaluating phase feedback that suppresses Robinson oscillations in order to obtain quiet operation of an infrared beam line.

Application of the extreme value theory to beam loss estimates in the SPIRAL2 linac based on large scale Monte Carlo computations

Directory of Open Access Journals (Sweden)

R. Duperrier

2006-04-01

Full Text Available The influence of random perturbations of high intensity accelerator elements on the beam losses is considered. This paper presents the error sensitivity study which has been performed for the SPIRAL2 linac in order to define the tolerances for the construction. The proposed driver aims to accelerate a 5 mA deuteron beam up to 20   A MeV and a 1 mA ion beam for q/A=1/3 up to 14.5 A MeV. It is a continuous wave regime linac, designed for a maximum efficiency in the transmission of intense beams and a tunable energy. It consists in an injector (two   ECRs   sources+LEBTs with the possibility to inject from several sources+radio frequency quadrupole followed by a superconducting section based on an array of independently phased cavities where the transverse focalization is performed with warm quadrupoles. The correction scheme and the expected losses are described. The extreme value theory is used to estimate the expected beam losses. The described method couples large scale computations to obtain probability distribution functions. The bootstrap technique is used to provide confidence intervals associated to the beam loss predictions. With such a method, it is possible to measure the risk to loose a few watts in this high power linac (up to 200 kW.

Novel integrated design framework for radio frequency quadrupoles

International Nuclear Information System (INIS)

Jolly, Simon; Easton, Matthew; Lawrie, Scott; Letchford, Alan; Pozimski, Jürgen; Savage, Peter

2014-01-01

A novel design framework for Radio Frequency Quadrupoles (RFQs), developed as part of the design of the FETS RFQ, is presented. This framework integrates several previously disparate steps in the design of RFQs, including the beam dynamics design, mechanical design, electromagnetic, thermal and mechanical modelling and beam dynamics simulations. Each stage of the design process is described in detail, including the various software options and reasons for the final software suite selected. Results are given for each of these steps, describing how each stage affects the overall design process, with an emphasis on the resulting design choices for the FETS RFQ

Conceptual design of a quadrupole magnet for eRHIC

Energy Technology Data Exchange (ETDEWEB)

Witte, H. [Brookhaven National Lab. (BNL), Upton, NY (United States); Berg, J. S. [Brookhaven National Lab. (BNL), Upton, NY (United States)

2015-05-03

eRHIC is a proposed upgrade to the existing Relativistic Heavy Ion Collider (RHIC) hadron facility at Brookhaven National Laboratory, which would allow collisions of up to 21 GeV polarized electrons with a variety of species from the existing RHIC accelerator. eRHIC employs an Energy Recovery Linac (ERL) and an FFAG lattice for the arcs. The arcs require open-midplane quadrupole magnets of up to 30 T/m gradient of good field quality. In this paper we explore initial quadrupole magnet design concepts based on permanent magnetic material which allow to modify the gradient during operation.

Mechanical Engineering of the Linac for the Spallation Neutron Source

International Nuclear Information System (INIS)

Bultman, N.K.; Chen, Z.; Collier, M.; Erickson, J.L.; Guthrie, A.; Hunter, W.T.; Ilg, T.; Meyer, R.K.; Snodgrass, N.L.

1999-01-01

The linac for the Spallation Neutron Source (SNS) Project will accelerate an average current of 1 mA of H - ions from 20 MeV to 1GeV for injection into an accumulator ring. The linac will be an intense source of H - ions and as such requires advanced design techniques to meet project technical goals as well as to minimize costs. The DTL, CCDTL and CCL are 466m long and operate at 805 MHz with a maximum H - input current of 28 mA and 7% rf duty factor. The Drift Tube Linac is a copper-plated steel structure using permanent magnetic quadrupoles. The Coupled-Cavity portions are brazed copper structures and use electromagnetic quads. RF losses in the copper are 80 MW, with total rf power supplied by 52 klystrons. Additionally, the linac is to be upgraded to the 2- and 4-MW beam power levels with no increase in duty factor. The authors give an overview of the linac mechanical engineering effort and discuss the special challenges and status of the effort

An improved integrally formed radio frequency quadrupole

Science.gov (United States)

Abbott, S.R.

1987-10-05

An improved radio frequency quadrupole is provided having an elongate housing with an elongate central axis and top, bottom and two side walls symmetrically disposed about the axis, and vanes formed integrally with the walls, the vanes each having a cross-section at right angles to the central axis which tapers inwardly toward the axis to form electrode tips spaced from each other by predetermined distances. Each of the four walls, and the vanes integral therewith, is a separate structural element having a central lengthwise plane passing through the tip of the vane, the walls having flat mounting surfaces at right angles to and parallel to the control plane, respectively, which are butted together to position the walls and vane tips relative to each other. 4 figs.

Practical design approach for trapezoidal modulation of a radio-frequency quadrupole

Directory of Open Access Journals (Sweden)

A. S. Plastun

2018-03-01

Full Text Available Trapezoidal modulation of quadrupole electrodes offers additional benefits to the concept of a radio-frequency quadrupole (RFQ. Because of the significant increase of the effective shunt impedance, RFQs with trapezoidal modulation have a reduced interelectrode voltage or resonator length as compared to conventional RFQs with sinusoidal modulation. This feature is especially valuable for RFQs operating in cw mode, since it reduces the required rf power. We develop a detailed procedure for the design of RFQ electrodes with trapezoidal modulation. With our design procedure and by properly choosing the trapezoidal cell parameters, we can easily control the peak surface fields in the RFQ to the same level as for sinusoidal cell modulation. The procedure is applied to the design of the electrodes for the ReA3 RFQ at Michigan State University.

H- ion sources for CERN's Linac4

Science.gov (United States)

Lettry, J.; Aguglia, D.; Coutron, Y.; Chaudet, E.; Dallocchio, A.; Gil Flores, J.; Hansen, J.; Mahner, E.; Mathot, S.; Mattei, S.; Midttun, O.; Moyret, P.; Nisbet, D.; O'Neil, M.; Paoluzzi, M.; Pasquino, C.; Pereira, H.; Arias, J. Sanchez; Schmitzer, C.; Scrivens, R.; Steyaert, D.

2013-02-01

The specifications set to the Linac4 ion source are: H- ion pulses of 0.5 ms duration, 80 mA intensity and 45 keV energy within a normalized emittance of 0.25 mmmrad RMS at a repetition rate of 2 Hz. In 2010, during the commissioning of a prototype based on H- production from the plasma volume, it was observed that the powerful co-extracted electron beam inherent to this type of ion source could destroy its electron beam dump well before reaching nominal parameters. However, the same source was able to provide 80 mA of protons mixed with a small fraction of H2+ and H3+ molecular ions. The commissioning of the radio frequency quadrupole accelerator (RFQ), beam chopper and H- beam diagnostics of the Linac4 are scheduled for 2012 and its final installation in the underground building is to start in 2013. Therefore, a crash program was launched in 2010 and reviewed in 2011 aiming at keeping the original Linac4 schedule with the following deliverables: Design and production of a volume ion source prototype suitable for 20-30 mA H- and 80 mA proton pulses at 45 keV by mid-2012. This first prototype will be dedicated to the commissioning of the low energy components of the Linac4. Design and production of a second prototype suitable for 40-50 mA H- based on an external RF solenoid plasma heating and cesiated-surface production mechanism in 2013 and a third prototype based on BNL's Magnetron aiming at reliable 2 Hz and 80 mA H- operations in 2014. In order to ease the future maintenance and allow operation with Ion sources based on three different production principles, an ion source "front end" providing alignment features, pulsed gas injection, pumping units, beam tuning capabilities and pulsed bipolar high voltage acceleration was designed and is being produced. This paper describes the progress of the Linac4 ion source program, the design of the Front end and first ion source prototype. Preliminary results of the summer 2012 commissioning are presented. The outlook on

Compact LINAC for deuterons

International Nuclear Information System (INIS)

Kurennoy, S.S.; O'Hara, J.F.; Rybarcyk, L.J.

2008-01-01

We are developing a compact deuteron-beam accelerator up to the deuteron energy of a few MeV based on room-temperature inter-digital H-mode (IH) accelerating structures with the transverse beam focusing using permanent-magnet quadrupoles (PMQ). Combining electromagnetic 3-D modeling with beam dynamics simulations and thermal-stress analysis, we show that IHPMQ structures provide very efficient and practical accelerators for light-ion beams of considerable currents at the beam velocities around a few percent of the speed of light. IH-structures with PMQ focusing following a short RFQ can also be beneficial in the front end of ion linacs.

A compact rf driven H- ion source for linac injection

International Nuclear Information System (INIS)

Rymer, J.P.; Engeman, G.A.; Hamm, R.W.; Potter, J.M.

1991-01-01

A compact rf driven H - ion source has been developed for use as an injector for the AccSys radio frequency quadrupole (RFQ) linacs. A multicusp magnetic bucket geometry developed at Lawrence Berkeley Laboratory confines the plasma created by an antenna driven by 35 kW (peak) of pulsed rf power at 1.8 MHz. A three electrode system is used to extract and accelerate the H - beam, which is then focused into the RFQ by an einzel lens. Permanent magnets in the extraction region sweep electrons onto the second electrode at energies up to half of the full acceleration voltage. A fast pulsed valve allows the hydrogen gas supply to be pulsed, thus minimizing the average gas flow rate into the system. The design features and performance data from the prototype are discussed

TOUTATIS: A radio frequency quadrupole code

Directory of Open Access Journals (Sweden)

Romuald Duperrier

2000-12-01

Full Text Available A cw high power linear accelerator can only work with very low particle losses and structure activation. At low energy, the radio frequency quadrupole (RFQ is an accelerator element that is very sensitive to losses. To design this structure, a good understanding of the beam dynamics is required. Generally, the reference code PARMTEQM is enough to design the accelerator. TOUTATIS has been written with the goals of cross-checking results and obtaining more reliable dynamics. This paper relates the different numerical methods used in the code. It is time based, using multigrids methods and adaptive mesh for a fine description of the forces without being time consuming. The field is calculated through a Poisson solver and the vanes are fully described, allowing it to properly simulate the coupling gaps and the RFQs extremities. Theoretical and experimental tests are also described and show a good agreement between simulations and reference cases.

Conceptual designs of beam choppers for RFQ linacs

International Nuclear Information System (INIS)

Nath, S.; Stevens, S.R. Jr.; Wangler, T.P.

1995-01-01

A design study at Los Alamos of a linac/accumulator ring facility for a pulsed neutron spallation source calls for an H - beam with a chopped structure of approximately 200-ns beam-free segments every 600-ns. The required angular impulse can easily be provided with existing pulse power technology and traveling wave structures with a transverse electric field similar to those now available. The deflected beam is then restored by suitable collimation. Chopping is relatively easily done at sufficiently low energies, where the beam is easily deflected, and beam powers are not too large. However, the energy should be high enough so that the space-charge blow-up of the beam can be controlled with adequate focusing. LAMPF presently uses a traveling-wave beam chopper at 750 keV, before injection into the drift tube linac (DTL). In the new linac designs, a radiofrequency quadrupole (RFQ) linac would typically bunch and accelerate the high intensity H - beam from 100 keV to 7 MeV. In this paper, the authors present concepts for beam-chopper systems both before and after the RFQ. The beam-optics designs are presented, together with numerical simulation results

Development of C6+ laser ion source and RFQ linac for carbon ion radiotherapy

Science.gov (United States)

Sako, T.; Yamaguchi, A.; Sato, K.; Goto, A.; Iwai, T.; Nayuki, T.; Nemoto, K.; Kayama, T.; Takeuchi, T.

2016-02-01

A prototype C6+ injector using a laser ion source has been developed for a compact synchrotron dedicated to carbon ion radiotherapy. The injector consists of a laser ion source and a 4-vane radio-frequency quadrupole (RFQ) linac. Ion beams are extracted from plasma and directly injected into the RFQ. A solenoid guides the low-energy beams into the RFQ. The RFQ is designed to accelerate high-intensity pulsed beams. A structure of monolithic vanes and cavities is adopted to reduce its power consumption. In beam acceleration tests, a solenoidal magnetic field set between the laser ion source and the RFQ helped increase both the peak currents before and after the RFQ by a factor of 4.

Development of C6+ laser ion source and RFQ linac for carbon ion radiotherapy

International Nuclear Information System (INIS)

Sako, T.; Yamaguchi, A.; Sato, K.; Goto, A.; Iwai, T.; Nayuki, T.; Nemoto, K.; Kayama, T.; Takeuchi, T.

2016-01-01

A prototype C 6+ injector using a laser ion source has been developed for a compact synchrotron dedicated to carbon ion radiotherapy. The injector consists of a laser ion source and a 4-vane radio-frequency quadrupole (RFQ) linac. Ion beams are extracted from plasma and directly injected into the RFQ. A solenoid guides the low-energy beams into the RFQ. The RFQ is designed to accelerate high-intensity pulsed beams. A structure of monolithic vanes and cavities is adopted to reduce its power consumption. In beam acceleration tests, a solenoidal magnetic field set between the laser ion source and the RFQ helped increase both the peak currents before and after the RFQ by a factor of 4

Conceptual design of compact heavy-ion inertial fusion driver with an r.f. LINAC with high acceleration rate

International Nuclear Information System (INIS)

Hattori, T.; Sasa, K.; Okamura, M.; Ito, T.; Tomizawa, H.; Katayose, T.; Hayashizaki, N.; Yoshida, T.; Isokawa, K.; Aoki, M.; Fujita, N.; Okada, M.

1996-01-01

The interdigital-H-type (IH) linear accelerator (LINAC) is well known for its high shunt impedance at low and medium particle velocities. Therefore, it can be used to operate efficiently with a high acceleration gradient. The IH LINAC cavity is able to generate 10 MV m -1 (average acceleration gradient) with focusing of the particles by a superconducting solenoid and quadrupole. The LINAC can accelerate particles with a charge to mass ratio (q/A) greater than 1/250 from 0.3 MeV a.m.u. -1 . In a compact heavy-ion inertial fusion driver design, the total effective length of the IH LINAC cavities is about 1250 m. (orig.)

CERN’s Linac4 H− sources: Status and operational results

International Nuclear Information System (INIS)

Lettry, J.; Aguglia, D.; Andersson, P.; Bertolo, S.; Butterworth, A.; Coutron, Y.; Dallocchio, A.; David, N.; Chaudet, E.; Fink, D.; Gil-Flores, J.; Garlasche, M.; Grudiev, A.; Guida, R.; Hansen, J.; Haase, M.; Jones, A.; Koszar, I.; Machado, C.; Mastrostefano, C.

2015-01-01

Two volume sources equipped with DESY and CERN plasma generators and a low voltage electron dump were operated at 45 kV in the Linac4 tunnel and on a dedicated test stand. These volume sources delivered approximately 20 mA and ensured the commissioning of the Radio Frequency Quadrupole accelerator and of the first section of the Drift Tube Linac. CERN’s prototype of a cesiated surface source equipped with this electron dump was operated continuously from November 2013 to April 2014 on the ion source test stand and is being commissioned in the Linac4 tunnel. Before cesiation, the prototype conditioned in volume mode provided up to 30 mA H − beam. Short cesiations, of the order of 10 mg effectively reduced the intensity of co-extracted electrons down to 2 - 8 times the H − current; this cesiated surface operation mode delivered up to 60 mA H − beam. An H − beam of the order of 40 mA was sustained up to four weeks operation with 500 μs pulses at 1.2s spacing. A new extraction was designed to match these beam properties. A copy of BNL’s magnetron produced at CERN was tested at BNL and delivered at 40 kV H − beam exceeding Linac4’s nominal intensity of 80 mA. In this contribution, the performances, dynamic response to cesiation, stability and availability of these prototypes are described. The needed optimization of the emittance of H − beam above 40 mA is presented, which requires an evolution of the front end that encompasses implementation of a large ceramic insulator

rf measurements and tuning of the 750 MHz radio frequency quadrupole

Science.gov (United States)

Koubek, Benjamin; Grudiev, Alexej; Timmins, Marc

2017-08-01

In the framework of the program on medical applications a compact 750 MHz RFQ has been designed and built to be used as an injector for a hadron therapy linac. This RFQ was designed to accelerate protons to an energy of 5 MeV within only 2 m length. It is divided into four segments and equipped with 32 tuners in total. The length of the RFQ corresponds to 5 λ which is considered to be close to the limit for field adjustment using only piston tuners. Moreover the high frequency, which is about double the frequency of existing RFQs, results in a sensitive structure and requires careful tuning. In this paper we present the tuning algorithm, the tuning procedure and rf measurements of the RFQ.

A theoretical study on directivity control of multiple-loudspeaker system with a quadrupole radiation pattern in low frequency range

Science.gov (United States)

Irwansyah, Kuse, Naoyuki; Usagawa, Tsuyoshi

2017-08-01

Directivity pattern of an ordinary loudspeaker becomes more directive at higher frequencies. However, because a single loudspeaker tends to radiate uniformly in all directions at low frequencies, reverberation from surrounding building walls may affect speech intelligibility when installing a multiple-loudspeaker system at crossroads. As an alternative, a sharply directive sound source is recommended to be used, but in many cases the directivity of an ordinary loudspeaker is less sharp at lower frequencies. Therefore, in order to overcome such a limitation, this paper discusses the possibility of using four loudspeakers under active control to realize a quadrupole radiation pattern in low frequency range. In this study, the radiation pattern of a primary loudspeaker and three secondary loudspeakers has been modelled. By placing the loudspeakers close together in the direction of 0°, 90°, 180°, and 270°, it was theoretically demonstrated that a quadrupole radiation pattern can be shaped in the target frequency range up to 600 Hz by simply controlling the directivity in three of four directions which are 45°, 135°, 225°, and 315°. Although, the radiation pattern model is far from realistic configurations and conditions, it is possible to realize a quadrupole radiation pattern in the low frequency range.

Development of C{sup 6+} laser ion source and RFQ linac for carbon ion radiotherapy

Energy Technology Data Exchange (ETDEWEB)

Sako, T., E-mail: takayuki1.sako@toshiba.co.jp; Yamaguchi, A.; Sato, K. [Toshiba Corporation, Yokohama 235-8522 (Japan); Goto, A.; Iwai, T.; Nayuki, T.; Nemoto, K.; Kayama, T. [Cancer Research Center, Yamagata University Faculty of Medicine, Yamagata 990-9585 (Japan); Takeuchi, T. [Accelerator Engineering Corporation, Chiba 263-0043 (Japan)

2016-02-15

A prototype C{sup 6+} injector using a laser ion source has been developed for a compact synchrotron dedicated to carbon ion radiotherapy. The injector consists of a laser ion source and a 4-vane radio-frequency quadrupole (RFQ) linac. Ion beams are extracted from plasma and directly injected into the RFQ. A solenoid guides the low-energy beams into the RFQ. The RFQ is designed to accelerate high-intensity pulsed beams. A structure of monolithic vanes and cavities is adopted to reduce its power consumption. In beam acceleration tests, a solenoidal magnetic field set between the laser ion source and the RFQ helped increase both the peak currents before and after the RFQ by a factor of 4.

Development of C⁶⁺ laser ion source and RFQ linac for carbon ion radiotherapy.

Science.gov (United States)

Sako, T; Yamaguchi, A; Sato, K; Goto, A; Iwai, T; Nayuki, T; Nemoto, K; Kayama, T; Takeuchi, T

2016-02-01

A prototype C(6+) injector using a laser ion source has been developed for a compact synchrotron dedicated to carbon ion radiotherapy. The injector consists of a laser ion source and a 4-vane radio-frequency quadrupole (RFQ) linac. Ion beams are extracted from plasma and directly injected into the RFQ. A solenoid guides the low-energy beams into the RFQ. The RFQ is designed to accelerate high-intensity pulsed beams. A structure of monolithic vanes and cavities is adopted to reduce its power consumption. In beam acceleration tests, a solenoidal magnetic field set between the laser ion source and the RFQ helped increase both the peak currents before and after the RFQ by a factor of 4.

Commissioning of the Linac4 RFQ at the 3 MeV test stand

CERN Document Server

Rossi, C; Bellodi, G; Broere, J; Brunner, O; Lombardi, A M; Balula, J M; Yanez, P M; Noirjean, J; Pasquino, C; Raich, U; Roncarolo, F; Vretenar, M; Desmons, M; France, A; Piquet, O

2013-01-01

Linac4, the future 160 MeV Hˉ injector to the CERN Proton Synchrotron Booster, is presently under construction at CERN as a first step of the planned upgrade of the LHC injectors. The low energy section of LINAC4, consisting of an ion source, a 352.2 MHz Radio Frequency Quadrupole (RFQ) and a chopper line is being commissioned in a dedicated test stand before installation in its final position in the tunnel. The RFQ is designed to accelerate a 45 keV, 70 mA, Hˉ beam to 3 MeV, with an efficiency of 95% while preserving the transverse emittance. The RFQ, a four-vane structure 3 m in length, has been designed in collaboration with CEA/IRFU and is has been fabricated at the CERN workshop. The precise fabrication has allowed achieving a field flatness of 1%. The completion of the accelerating structure in September 2012 was followed by a complete series of bead-pull measurements and by high-power conditioning to the nominal power of 0.39 MW corresponding to a voltage of 78 kV across the 3 meters. Measurements wi...

Development of a 352 MHz Cell-Coupled Drift Tube Linac Prototype

CERN Document Server

Cuvet, Y; Völlinger, C; Vretenar, M; Gerigk, F

2004-01-01

At linac energies above 40 MeV, alternative structures to the conventional Drift Tube Linac can be used to increase efficiency and to simplify construction and alignment. In the frame of the R&D activities for the CERN SPL and Linac4, a prototype of Cell-Coupled Drift Tube Linac (CCDTL) at 352 MHz has been designed and built. This particular CCDTL concept is intended to cover the energy range from 40 to 90 MeV and consists of modules of ~5 m length made of 3-gap DTL tanks linked by coupling cells. The focusing quadrupoles are placed between tanks, and are aligned independently from the RF structure. The CCDTL prototype consists of two half tanks connected by a coupling cell and requires an RF power of 120 kW to achieve the design gradient. RF tests will be made at low and high power, the latter up to a 20% duty cycle. This paper introduces the main features of this CCDTL design and describes the RF and mechanical design of the prototype.

New newtron time-of-flight (NTOF) facilities at the Brookhaven 200-MeV Linac

International Nuclear Information System (INIS)

Ward, T.E.; Alessi, J.; Brennan, J.; Grand, P.; Lankshear, R.; Snead, C.L.; Tsoupas, N.; Zucker, M.

1988-01-01

The installation of a new beam chopper and radio-frequency quadrupole (RFQ) preinjector (750 keV) at the Brookhaven National Laboratory (BNL) 200-MeV Linac will enable single micropulse selection (pulse width 9 pμ pulse with dc-average beam currents of 50 nA-1 μA routinely available. The NTOF facilities consists of 30-100 meter flight paths at angles of 0, 12, 30, 45, 90, and 135/degree/. Lower energies of 93, 117, 139, 161, and 181 MeV are also available as well as polarized beams at much reduced intensities. The present paper describes the new facilities, and the capabilities of future improvements and upgrades, for use in the BNL intermediate energy (p,n) experimental program. 7 refs., 2 figs., 1 tab

Theoretical investigation of flute modes in a magnetic quadrupole

International Nuclear Information System (INIS)

Wu, H.S.

1988-01-01

This research developed theories and conducted numerical investigations of electrostatic flute modes in a plasma confined in a magnetic quadrupole. Chapter I presents the discussion of relevant background. Chapter II contains a brief discussion of the basic flute-mode operator L 0 for intermediate- and low-frequency regimes. Chapter III develops a simple theory for a flute mode with frequency between the electron and ion bounce frequencies in the uniform density and temperature regions of a magnetic quadrupole. The frequency is predicted to be inversely proportional to the wave number. Chapter IV describes the kinetic approach. Chapter V contains the derivation of an eigenvalue equation for electrostatic waves with frequencies below the ion frequency in the private flux region of a magnetic quadrupole. Chapter VI develops a theory for electrostatic waves with frequency below the ion bounce frequency in the shared flux region of a magnetic quadrupole. Chapter VII contains the derivation of a dispersion equation for flute modes with frequencies between the electron and ion bounce frequencies in a plasma confined to a magnetic quadrupole. Chapter VIII presents a summary of the research described

Development of a radio-frequency quadrupole cooler for high beam currents

Science.gov (United States)

Boussaid, Ramzi; Ban, G.; Quéméner, G.; Merrer, Y.; Lorry, J.

2017-12-01

The SHIRaC prototype is a recently developed radio-frequency quadrupole (RFQ) beam cooler with an improved optics design to deliver the required beam quality to a high resolution separator (HRS). For an isobaric separation of isotopes, the HRS demands beams with emittance not exceeding 3 π mm mrad and longitudinal energy spread ˜1 eV . Simulation studies showed a significant contribution of the buffer gas diffusion, space charge effect and mainly the rf fringe field to degrade the achieved beam quality at the RFQ exit. A miniature rf quadrupole (μ RFQ ) has been implemented at that exit to remove the degrading effects and provide beams with 1 eV of energy spread and around 1.75 π mm mrad of emittance for 4 Pa gas pressure. This solution enables also to transmit more than 60% of the incoming ions for currents up to 1 μ A . Detailed studies of this development are presented and discussed in this paper. Transport of beams from SHIRaC towards the HRS has been done with an electrostatic quadrupole triplet. Simulations and first experimental tests showed that more than 95% of ions can reach the HRS. Because SPIRAL-2 beams are of high current and very radioactive, the buffer gas will be highly contaminated. Safe maintenance of the SHIRaC beam line needs exceptional treatment of radioactive contaminants. For that, special vinyl sleep should be mounted on elements to be maintained. A detailed maintenance process will be presented.

Detuning effect in a traveling wave type linac

International Nuclear Information System (INIS)

Arai, Shigeaki.

1981-10-01

Detailed measurement of acceleration characteristics has been performed on a 15 MeV electron linac as the injector of the electron synchrotron at Institute for Nuclear Study, University of Tokyo. Remarkable feature of the results is that the energy gain as well as the energy spread of the output beam, are optimized when the linac is operated with the microwave whose frequency is higher than the resonant frequency of the accelerator waveguide. The difference of this operating frequency from the resonant frequency grows up as the beam intensity is increased, and amounts to 250 KHz when the beam intensity is 350 mA. In order to clarify the mechanism of the phenomena, the interaction of electron beam with the microwave in the accelerator structure of traveling wave type, is examined on the linac and also on a test accelerator structure. For the analysis of the experimental results, the normal mode method which has been used for standing wave cavities, is developed so as to be applied to the accelerator structure of traveling wave type. The results of analysis show that the observed phenomena at INS linac are caused by the resonant frequency shift, detuning, due to the reactive beam loading and this detuning effects are compensated by use of the microwave of higher frequency. Thus the detuning effects are significant even in the traveling wave type linac composed of buncher and regular sections as well as in the standing wave type accelerator structure. (author)

Magnetron based high energy S-band linac system

International Nuclear Information System (INIS)

Tiwari, T.; Krishnan, R.; Phatangare, Manoj

2012-01-01

This paper deals with the study of magnetron based high energy S-band linear accelerator (linac) system operating at spot frequency 2.998 GHz. The energy and dose are two important parameters of linac system which depend on input power of microwave source and length of linac tube. Here the author has studied how these parameters can be improved for side coupled standing wave S-band linac system

Pulsed-focusing recirculating linacs for muon acceleration

Energy Technology Data Exchange (ETDEWEB)

Johnson, Rolland [Muons, Inc., Batavia, IL (United States)

2014-12-31

Since the muon has a short lifetime, fast acceleration is essential for high-energy applications such as muon colliders, Higgs factories, or neutrino factories. The best one can do is to make a linear accelerator with the highest possible accelerating gradient to make the accelerating time as short as possible. However, the cost of such a single linear accelerator is prohibitively large due to expensive power sources, cavities, tunnels, and related infrastructure. As was demonstrated in the Thomas Jefferson Accelerator Facility (Jefferson Lab) Continuous Electron Beam Accelerator Facility (CEBAF), an elegant solution to reduce cost is to use magnetic return arcs to recirculate the beam through the accelerating RF cavities many times, where they gain energy on each pass. In such a Recirculating Linear Accelerator (RLA), the magnetic focusing strength diminishes as the beam energy increases in a conventional linac that has constant strength quadrupoles. After some number of passes the focusing strength is insufficient to keep the beam from going unstable and being lost. In this project, the use of fast pulsed quadrupoles in the linac sections was considered for stronger focusing as a function of time to allow more successive passes of a muon beam in a recirculating linear accelerator. In one simulation, it was shown that the number of passes could be increased from 8 to 12 using pulsed magnet designs that have been developed and tested. This could reduce the cost of linac sections of a muon RLA by 8/12, where more improvement is still possible. The expense of a greater number of passes and corresponding number of return arcs was also addressed in this project by exploring the use of ramped or FFAG-style magnets in the return arcs. A better solution, invented in this project, is to use combined-function dipole-quadrupole magnets to simultaneously transport two beams of different energies through one magnet string to reduce costs of return arcs by almost a factor of

Vane fabrication for the proof-of-principle radio-frequency quadrupole accelerator

International Nuclear Information System (INIS)

Williams, S.W.; Potter, J.M.

1981-01-01

The electrodes for the Proof-of-Principle (POP) Radio-Frequency Quadrupole (RFQ) accelerator were machined on a numerically controlled, three-axis, vertical mill. These pole tips, or vanes, were prepared for, and used, in the successful demonstration of RFQ practicality at Los Alamos National Laboratory in February 1980. The data set that described the vanes contained about 10 million bits of tool position data. The vanes were cut from OFHC copper blanks. The tolerances achieved were approximately +- 0.005 cm. The design and manufacturing procedures are described

CERN Linac4. The space charge challenge

Energy Technology Data Exchange (ETDEWEB)

Hein, Lutz Matthias

2013-08-06

In the first phase of the upgrade program of the CERN accelerator complex the proton injector Linac2 will be replaced by a new, normal-conducting H-ion Linac, Linac4, allowing a significant increase of the proton flux intensity along the downstream accelerator complex. In the design of Linac4 three beam transport sections are implemented to match the beam between the different accelerator elements and to model the longitudinal pulse structure. These three beam transport sections, which are the most critical locations in terms of beam quality preservation, are in the focus of this thesis. During the work of this thesis the Low Energy Beam Transport (LEBT), which is required to match the source beam to the radiofrequency quadrupole (RFQ), has been commissioned and its beam dynamics re-constructed. The measurement campaign used to reconstruct the LEBT beam dynamics was performed with the aim to prepare the RFQ commissioning and to maximise the LEBT performance. Downstream of the Linac4 accelerator the beam is transported along a 180 m long transfer line to the Proton Synchrotron Booster (PS-Booster). The transfer line optics was studied, optimised and sections were completely re-designed. The new transfer line optics is characterised by an improved preservation of the beam emittance, higher stability of the optical solution with respect to alignment errors and field jitters of the transfer line magnets and it is matched to each of the PS-Booster injection schemes. In a concluding ''Start-To-End'' simulation based on the measured beam characteristics at the LEBT exit the beam dynamics of the downstream Linac, including the transfer line, was calculated. To minimise particle losses within acceptable emittance preservation the beam optics of the Medium Energy Beam Transport (MEBT) was adapted to the measured beam parameters. This ''Start-To-End'' simulation was performed to identify critical sections of the Linac4 beam dynamics and

Operational characteristics of a 100-mA, 2-MeV radio-frequency quadrupole

International Nuclear Information System (INIS)

Johnson, K.F.; Cottingame, W.B.; Bolme, G.O.; Fortgang, C.M.; Ingalls, W.B.; Marquardt, J.; Rusthoi, D.P.; Sander, O.R.; Smith, M.; Worth, G.T.

1993-01-01

A 100-mA, 2.07-MeV Radio-Frequency Quadrupole (RFQ III) has been commissioned and operated routinely on the Accelerator Test Stand (ATS) [1] at Los Alamos National Laboratory. To characterize the RFQ output beam dynamics, measurements were made of the beam transmission and of the transverse and longitudinal phase-space distributions. Data were taken for different RFQ III operating conditions and compared to simulations

Stabilized operation of the Spallation Neutron Source radio-frequency quadrupole

Directory of Open Access Journals (Sweden)

Sang-ho Kim

2010-07-01

Full Text Available The Spallation Neutron Source (SNS radio-frequency quadrupole (RFQ had resonance control instabilities at duty factors higher than approximately 4%. Systematic investigations have been carried out to understand the cause of the instability and to ensure the operational stability of the RFQ. The most critical source of the instability is revealed to be an interaction between hydrogen released by beam bombardments and the RFQ rf field resulting in a discharge, which consumes additional rf power and could cause the RFQ to operate in an unstable region. This paper reports improvement of the SNS RFQ operational stability based on the findings during the SNS operation.

Parallelization of a beam dynamics code and first large scale radio frequency quadrupole simulations

Directory of Open Access Journals (Sweden)

J. Xu

2007-01-01

Full Text Available The design and operation support of hadron (proton and heavy-ion linear accelerators require substantial use of beam dynamics simulation tools. The beam dynamics code TRACK has been originally developed at Argonne National Laboratory (ANL to fulfill the special requirements of the rare isotope accelerator (RIA accelerator systems. From the beginning, the code has been developed to make it useful in the three stages of a linear accelerator project, namely, the design, commissioning, and operation of the machine. To realize this concept, the code has unique features such as end-to-end simulations from the ion source to the final beam destination and automatic procedures for tuning of a multiple charge state heavy-ion beam. The TRACK code has become a general beam dynamics code for hadron linacs and has found wide applications worldwide. Until recently, the code has remained serial except for a simple parallelization used for the simulation of multiple seeds to study the machine errors. To speed up computation, the TRACK Poisson solver has been parallelized. This paper discusses different parallel models for solving the Poisson equation with the primary goal to extend the scalability of the code onto 1024 and more processors of the new generation of supercomputers known as BlueGene (BG/L. Domain decomposition techniques have been adapted and incorporated into the parallel version of the TRACK code. To demonstrate the new capabilities of the parallelized TRACK code, the dynamics of a 45 mA proton beam represented by 10^{8} particles has been simulated through the 325 MHz radio frequency quadrupole and initial accelerator section of the proposed FNAL proton driver. The results show the benefits and advantages of large-scale parallel computing in beam dynamics simulations.

Computation of Normal Conducting and Superconducting Linear Accelerator (LINAC) Availabilities

International Nuclear Information System (INIS)

Haire, M.J.

2000-01-01

A brief study was conducted to roughly estimate the availability of a superconducting (SC) linear accelerator (LINAC) as compared to a normal conducting (NC) one. Potentially, SC radio frequency cavities have substantial reserve capability, which allows them to compensate for failed cavities, thus increasing the availability of the overall LINAC. In the initial SC design, there is a klystron and associated equipment (e.g., power supply) for every cavity of an SC LINAC. On the other hand, a single klystron may service eight cavities in the NC LINAC. This study modeled that portion of the Spallation Neutron Source LINAC (between 200 and 1,000 MeV) that is initially proposed for conversion from NC to SC technology. Equipment common to both designs was not evaluated. Tabular fault-tree calculations and computer-event-driven simulation (EDS) computer computations were performed. The estimated gain in availability when using the SC option ranges from 3 to 13% under certain equipment and conditions and spatial separation requirements. The availability of an NC LINAC is estimated to be 83%. Tabular fault-tree calculations and computer EDS modeling gave the same 83% answer to within one-tenth of a percent for the NC case. Tabular fault-tree calculations of the availability of the SC LINAC (where a klystron and associated equipment drive a single cavity) give 97%, whereas EDS computer calculations give 96%, a disagreement of only 1%. This result may be somewhat fortuitous because of limitations of tabular fault-tree calculations. For example, tabular fault-tree calculations can not handle spatial effects (separation distance between failures), equipment network configurations, and some failure combinations. EDS computer modeling of various equipment configurations were examined. When there is a klystron and associated equipment for every cavity and adjacent cavity, failure can be tolerated and the SC availability was estimated to be 96%. SC availability decreased as

Simulation studies of the LAMPF proton linac

International Nuclear Information System (INIS)

Garnett, R.W.; Gray, E.R.; Rybarcyk, L.J.; Wangler, T.P.

1995-01-01

The LAMPF accelerator consists of two 0.75-MeV injectors, one for H + and the other for H - , a separate low-energy beam transport (LEBT) line for each beam species, a 0.75 to 100-MeV drift-tube linac (DTL) operating at 201.25-MHz, a 100-MeV transition region (TR), and a 100 to 800-MeV side-coupled linac (SCL) operating at 805-MHz. Each LEBT line consists of a series of quadrupoles to transport and transversely match the beam. The LEBT also contains a prebuncher, a main buncher, and an electrostatic deflector. The deflector is used to limit the fraction of a macropulse which is seen by the beam diagnostics throughout the linac. The DTL consists of four rf tanks and uses singlet FODO transverse focusing. The focusing period is doubled in the last two tanks by placing a quadrupole only in every other drift-tube. Doublet FDO transverse focusing is used in the SCL. The TR consists of separate transport lines for the H + and H - beams. The pathlengths for the two beams differ, by introducing bends, so as to delay arrival of one beam relative to the other and thereby produce the desired macropulse time structure. Peak beam currents typically range from 12 to 18-mA for varying macropulse lengths which give an average beam current of 1-mA. The number of particles per bunch is of the order 10 8 . The work presented here is an extension of previous work. The authors have attempted to do a more complete simulation by including modeling of the LEBT. No measurements of the longitudinal structure of the beam, except phase-scans, are performed at LAMPF. The authors show that, based on simulation results, the primary causes of beam spill are inefficient longitudinal capture and the lack of longitudinal matching. Measurements to support these claims are not presently made at LAMPF. However, agreement between measurement and simulation for the transverse beam properties and transmissions serve to benchmark the simulations

rf measurements and tuning of the 750 MHz radio frequency quadrupole

Directory of Open Access Journals (Sweden)

Benjamin Koubek

2017-08-01

Full Text Available In the framework of the program on medical applications a compact 750 MHz RFQ has been designed and built to be used as an injector for a hadron therapy linac. This RFQ was designed to accelerate protons to an energy of 5 MeV within only 2 m length. It is divided into four segments and equipped with 32 tuners in total. The length of the RFQ corresponds to 5λ which is considered to be close to the limit for field adjustment using only piston tuners. Moreover the high frequency, which is about double the frequency of existing RFQs, results in a sensitive structure and requires careful tuning. In this paper we present the tuning algorithm, the tuning procedure and rf measurements of the RFQ.

Electron linac injector developments

International Nuclear Information System (INIS)

Fraser, J.S.

1986-01-01

There is a continuing demand for improved injectors for electron linacs. Free-electron laser (FEL) oscillators require pulse trains of high brightness and, in some applications, high average power at the same time. Wakefield-accelerator and laser-acceleration experiments require isolated bunches of high peak brightness. Experiments with alkali-halide photoemissive and thermionic electron sources in rf cavities for injector applications are described. For isolated pulses, metal photocathodes (illuminated by intense laser pulses) are being employed. Reduced emittance growth in high-peak-current electron injectors may be achieved by linearizing the cavity electric field's radial component and by using high field strengths at the expense of lower shunt impedance. Harmonically excited cavities have been proposed for enlarging the phase acceptance of linac cavities and thereby reducing the energy spread produced in the acceleration process. Operation of injector linacs at a subharmonic of the main linac frequency is also proposed for enlarging the phase acceptance

Operating experience with the ALS linac

International Nuclear Information System (INIS)

Selph, F.; Massoletti, D.

1991-05-01

The linac injector for the Advanced Light Source (ALS) at LBL was recently put into operation. Energy is 50 MeV, frequency 3 GHz. The electron gun delivers up to 6nC in a 3.0-ns bunch at 120 kV. A train of bunches is injected into a 1-Hz booster and accelerated to 1.5 GHz for storage ring injection. A magnetic analysis system is used for optimizing the linac. Measured beam properties from the gun and after acceleration in the linac are described. 9 refs., 3 figs

A Trajectory Correction based on Multi-Step Lining-up for the CLIC Main Linac

CERN Document Server

D'Amico, T E

1999-01-01

In the CLIC main linac it is very important to minimise the trajectory excursion and consequently the emittance dilution in order to obtain the required luminosity. Several algorithms have been proposed and lately the ballistic method has proved to be very effective. The trajectory method described in this Note retains the main advantages of the latter while adding some interesting features. It is based on the separation of the unknown variables like the quadrupole misalignments, the offset and slope of the injection straight line and the misalignments of the beam position monitors (BPM). This is achieved by referring the trajectory relatively to the injection line and not to the average pre-alignment line and by using two trajectories each corresponding to slightly different quadrupole strengths. A reference straight line is then derived onto which the beam is bent by a kick obtained by moving the first quadrupole. The other quadrupoles are then aligned on that line. The quality of the correction depends mai...

The development of compact magnetic quadrupoles for ILSE

International Nuclear Information System (INIS)

Faltens, A.; Mukherjee, S.; Brady, V.

1990-08-01

Magnetic focussing is selected for the 4 MeV to 10 MeV section of the Induction Linac Systems Experiments (ILSE) to study the transport of magnetically focussed spacecharge-dominated beams and to explore the engineering problems in accurate positioning of the magnetic fields in an array of quadrupoles. A prototype development program for such magnets is currently under way. A compact design was selected to decrease the overall accelerator diameter and its cost. The design evolved from a cosine 2θ current distribution, corrected for end effects. Current-dominated magnets are used in a pulsed mode to allow higher current densities compared to standard dc water-cooled conductors. The POISSON and MAFCO codes were used in the design of the magnets. The construction of the quadrupoles is aimed at achieving location accuracy of the magnetic center to within 1 mil (2.54 x 10 -5 m) of the mechanical center

Crossbar H-mode drift-tube linac design with alternative phase focusing for muon linac

Science.gov (United States)

Otani, M.; Futatsukawa, K.; Hasegawa, K.; Kitamura, R.; Kondo, Y.; Kurennoy, S.

2017-07-01

We have developed a Crossbar H-mode (CH) drift-tube linac (DTL) design with an alternative phase focusing (APF) scheme for a muon linac, in order to measure the anomalous magnetic moment and electric dipole moment (EDM) of muons at the Japan Proton Accelerator Research Complex (J-PARC). The CH-DTL accelerates muons from β = v/c = 0.08 to 0.28 at an operational frequency of 324 MHz. The design and results are described in this paper.

Linac4 45 keV Proton Beam Measurements

CERN Document Server

Bellodi, G; Hein, L M; Lallement, J-B; Lombardi, A M; Midttun, O; Scrivens, R; Posocco, P A

2013-01-01

Linac4 is a 160 MeV normal-conducting H- linear accelerator, which will replace the 50 MeV proton Linac2 as injector for the CERN proton complex. Commissioning of the low energy part - comprising the H - source, a 45 keV Low Energy Beam Transport line (LEBT), a 3 MeV Radiofrequency Quadrupole (RFQ) and a Medium Energy Beam Transport (MEBT) - will start in fall 2012 on a dedicated test stand installation. In preparation to this, preliminary measurements were taken using a 45 keV proton source and a temporary LEBT setup, with the aim of characterising the output beam by comparison with the predictions of simulations. At the same time this allowed a first verification of the functionalities of diagnostics instrumentation and acquisition software tools. Measurements of beam profile, emittance and intensity were taken in three different setups: right after the source, after the first and after the second LEBT solenoids respectively. Particle distributions were reconstructed from emittance scan...

Design and construction of superconducting quadrupole magnets for ion beam fusion

International Nuclear Information System (INIS)

Wang, S.T.; Ludwig, H.; Turner, L.R.

1978-01-01

A high gradient superconducting quadrupole has been designed and developed as the heavy ion beam focussing element in the low velocity portions of an rf linac for the Argonne Ion Beam Fusion Reactor. The quadrupole magnets will require an extremely short magnet coil length (approximately 20 cm to 30 cm) and extremely high central gradients (approximately 100 T/m to 200 T/m). The useful warm bore will be about 4 to 6 cm and the integral gradient homogeneity should be constant to +-5% over the useful warm bore. Special techniques have been developed which are especially suitable for multilayer coil winding and coil assembly with high average current density over the coil cross section. A 5-layer quadrupole with 9 cm winding bore has been built and tested to the full performance of about 100 T/m with little training. The achieved average current density is 22,000 A/cm 2 at a peak field in conductor of about 5.0 T. An 8-layer quadrupole is under construction for a design gradient of 140 T/m over 9 cm winding bore. The peak field will be about 7.2 T

Survey of radio-frequency quadrupole accelerators

International Nuclear Information System (INIS)

Billen, J.H.

1984-01-01

Over the last several years the RFQ has proved to be a very flexible low-energy accelerator for bunching and accelerating both low- and high-current beams. It uses low-voltage dc injectors, has excellent bunching properties and high transmission efficiency. Applications include injectors for higher energy machines, such as drift-tube linacs, cyclotrons, or synchrotrons. The RFQ can also be used alone for applications that require a fixed-energy beam. 41 references, 4 figures, 2 tables

Updated layout of the LINAC4 transfer line to the PS Booster (Green Field Option)

CERN Document Server

Bellodi, G; Lallement, J B; Lombardi, A M; CERN. Geneva. AB Department

2008-01-01

At the time of defining the site of Linac4 and its integration in the complex of existing infrastructure at CERN (together with the plans for a future Superconducting Proton Linac), a series of radiation protection issues emerged that have since prompted a revision of the Linac4 to PSB transfer line layout, as was described in the document AB‐Note‐2007‐037. For radiological safety reasons the distance between the planned SPL tunnel and the basement of building 513 had to be increased, and this led to the decision to lower the Linac4 machine by 2.5m. A vertical ramp was consequently introduced in the transfer line to raise the beam at the same level of LINAC2/PSB for connection to the existing transfer line. A series of error study runs has been carried out on the modified layout to have an estimate of the losses induced by quadrupole alignment and field errors. The two worst cases of each error family have been used as case studies to test the efficiency of possible steering strategies in...

Adjustable permanent quadrupoles for the next linear collider

International Nuclear Information System (INIS)

Volk, James T.

2001-01-01

The proposed Next Linear Collider (NLC) will require over 1400 adjustable quadrupoles between the main linacs' accelerator structures. These 12.7 mm bore quadrupoles will have a range of integrated strength from 0.6 to 138 Tesla, with a maximum gradient of 141 Tesla per meter, an adjustment range of +0 to -20% and effective lengths from 324 mm to 972 mm. The magnetic center must remain stable to within 1 micron during the 20% adjustment. In an effort to reduce costs and increase reliability, several designs using hybrid permanent magnets have been developed. Four different prototypes have been built. All magnets have iron poles and use Samarium Cobalt to provide the magnetic fields. Two use rotating permanent magnetic material to vary the gradient, one uses a sliding shunt to vary the gradient and the fourth uses counter rotating magnets. Preliminary data on gradient strength, temperature stability, and magnetic center position stability are presented. These data are compared to an equivalent electromagnetic prototype

Adjustable Permanent Quadrupoles for the Next Linear Collider

International Nuclear Information System (INIS)

Spencer, Cherrill M

2001-01-01

The proposed Next Linear Collider (NLC) will require over 1400 adjustable quadrupoles between the main linacs' accelerator structures. These 12.7 mm bore quadrupoles will have a range of integrated strength from 0.6 to 138 Tesla, with a maximum gradient of 141 Tesla per meter, an adjustment range of +0 to - 20% and effective lengths from 324 mm to 972 mm. The magnetic center must remain stable to within 1 micron during the 20% adjustment. In an effort to reduce costs and increase reliability, several designs using hybrid permanent magnets have been developed. Four different prototypes have been built. All magnets have iron poles and use Samarium Cobalt to provide the magnetic fields. Two use rotating permanent magnetic material to vary the gradient, one uses a sliding shunt to vary the gradient and the fourth uses counter rotating magnets. Preliminary data on gradient strength, temperature stability, and magnetic center position stability are presented. These data are compared to an equivalent electromagnetic prototype

Radio frequency focused interdigital linear accelerator

Science.gov (United States)

Swenson, Donald A.; Starling, W. Joel

2006-08-29

An interdigital (Wideroe) linear accelerator employing drift tubes, and associated support stems that couple to both the longitudinal and support stem electromagnetic fields of the linac, creating rf quadrupole fields along the axis of the linac to provide transverse focusing for the particle beam. Each drift tube comprises two separate electrodes operating at different electrical potentials as determined by cavity rf fields. Each electrode supports two fingers, pointing towards the opposite end of the drift tube, forming a four-finger geometry that produces an rf quadrupole field distribution along its axis. The fundamental periodicity of the structure is equal to one half of the particle wavelength .beta..lamda., where .beta. is the particle velocity in units of the velocity of light and .lamda. is the free space wavelength of the rf. Particles are accelerated in the gaps between drift tubes. The particle beam is focused in regions inside the drift tubes.

Measurements of quadrupole interaction frequencies of long-lived isomers with the level mixing spectroscopy (LEMS) method

International Nuclear Information System (INIS)

Neyens, G.; Nouwen, R.; S'heeren, G.; Bergh, M. van den; Coussement, R.

1993-01-01

The level mixing spectroscopy (LEMS) method has proven to be a very useful method to determine the quadrupole interaction frequency of an isomer in a solid host. Especially in the 'difficult' cases, e.g. when the isomeric lifetime is very long or its spin is very high, the method yields valuable information which is not accessible with other methods (such as TDPAD). Since the development of the method some years ago, many experiments have been performed on high spin isomers in the lead region. The static quadrupole moment of isomers with lifetimes ranging from 20 ns up to 13 ms and spins up to 65/2h have been determined in neutron deficient isotopes of Bi, At, Fr and Ra. (orig.)

Development of the low energy linac systems

International Nuclear Information System (INIS)

Cho, Yong Sub; Kwon, H. J.; Kim, Y. H.

2005-08-01

The project 'Development of the Low Energy Linac System' is aiming to develop the 20 MeV proton linac system. This consists of a 50 keV proton injector, a 3 MeV RFQ, and a 20 MeV DTL. We obtained the first beam signal after the 20 MeV linac. The high power switch installed in the ion source supplies the pulsed beam into the following LEBT. The pulse operation was successfully tested. The main role of the LEBT is to match the beam into the 3 MeV RFQ. The total length of the four-vane type RFQ is about 3.26m. For the field stabilization, we used the resonant coupling scheme and dipole stabilizer rods. An 1 MW klystron supplies the RF power into the RFQ. After tuning, the field deviation of the quadrupole mode is less than 2% of the design value and the dipole fraction is less than 5% of the operating mode. The following accelerating structure is DTL which accelerate 20 mA proton beams up to 20 MeV. It consists of 4 tanks and the length of each tank is less than 5 m. The lattice is FFDD type and the integrated fields of the quadrupole magnets are 1.75 T. The inner walls of the tanks are copper-plated by PR plating method. The thickness is 100m with the roughness of 0.3m. Each drift tube consists of 6 parts and assembled by e-beam welding. The tanks and drift tubes are aligned under the installation limit of 50m by using the laser-tracker. The tuning by the slug tuners and post couplers results in the field uniformity of 2% and field sensitivity of 100%/MHz. In order to detect the beam signal, we installed the Faraday cup after the RFQ or the DTL. For the RFQ, we observed the beam of 12 A under the forward RF power of 450 kW. The beam current after DTL is about 0.5 A when RF power of 150 kW was fed into each tank

Linac4 low energy beam measurements with negative hydrogen ions

Energy Technology Data Exchange (ETDEWEB)

Scrivens, R., E-mail: richard.scrivens@cern.ch; Bellodi, G.; Crettiez, O.; Dimov, V.; Gerard, D.; Granemann Souza, E.; Guida, R.; Hansen, J.; Lallement, J.-B.; Lettry, J.; Lombardi, A.; Midttun, Ø.; Pasquino, C.; Raich, U.; Riffaud, B.; Roncarolo, F.; Valerio-Lizarraga, C. A.; Wallner, J.; Yarmohammadi Satri, M.; Zickler, T. [CERN, 1211 Geneva 23 (Switzerland)

2014-02-15

Linac4, a 160 MeV normal-conducting H{sup −} linear accelerator, is the first step in the upgrade of the beam intensity available from the LHC proton injectors at CERN. The Linac4 Low Energy Beam Transport (LEBT) line from the pulsed 2 MHz RF driven ion source, to the 352 MHz RFQ (Radiofrequency Quadrupole) has been built and installed at a test stand, and has been used to transport and match to the RFQ a pulsed 14 mA H{sup −} beam at 45 keV. A temporary slit-and-grid emittance measurement system has been put in place to characterize the beam delivered to the RFQ. In this paper a description of the LEBT and its beam diagnostics is given, and the results of beam emittance measurements and beam transmission measurements through the RFQ are compared with the expectation from simulations.

RF System description for the ground test accelerator radio-frequency quadrupole

International Nuclear Information System (INIS)

Regan, A.H.; Brittain, D.; Rees, D.E.; Ziomek, D.

1992-01-01

This paper describes the RF system being used to provide RF power and to control the cavity field for the ground test accelerator (GTA) radio-frequency quadrupole (RFQ). The RF system consists of a low-level RF (LLRF) control system, and RF Reference generation subsystem, and a tetrode as a high-power amplifier (HPA) that can deliver up to 300 kW of peak power to the RFQ cavity at a 2% duty factor. The LLRF control system implements in-phase and quadrature (I and Q) control to maintain the cavity field within tolerances of 0.5% in amplitude and 0.5 degrees in phase in the presence of beam-induced instabilities

Adjustable Permanent Quadrupoles Using Rotating Magnet Material Rods for the Next Linear Collider.

CERN Document Server

Spencer, C M

2002-01-01

The proposed Next Linear Collider (NLC) will require over 1400 adjustable quadrupoles between the main linacs' accelerator structures. These 12.7 mm bore quadrupoles will have a range of integrated strength from 0.6 to 132 Tesla, with a maximum gradient of 135 Tesla per meter, an adjustment range of +0 -20% and effective lengths from 324 mm to 972 mm. The magnetic center must remain stable to within 1 micrometer during the 20% adjustment. In an effort to reduce estimated costs and increase reliability, several designs using hybrid permanent magnets have been developed. All magnets have iron poles and use either Samarium Cobalt or Neodymium Iron to provide the magnetic fields. Two prototypes use rotating rods containing permanent magnetic material to vary the gradient. Gradient changes of 20% and center shifts of less than 20 microns have been measured. These data are compared to an equivalent electromagnet prototype. See High Reliability Prototype Quadrupole for the Next Linear Collider by C.E Rago, C.M SPENC...

ARIEL e-LINAC: Commissioning and Development

Science.gov (United States)

Laxdal, R. E.; Zvyagintsev, V.

2016-09-01

A superconducting electron Linac (e-Linac) will be a part of the ARIEL facility for the production of radioactive ion beams (RIB) at TRIUMF. The e-Linac will consist of five 1.3GHz 9-cell cavities in three cryomodules delivering a 50MeV 10mA beam. The baseline operation will be single pass but a re-circulating ring is planned to allow either energy boost or energy recovery operation. The first stage of the accelerator which consists of two cryomodules has been successfully commissioned in 2014. The paper will discuss the superconducting radio-frequency (SRF) challenges of the accelerator. Cavities, crymodules and RF system design, preparation, and performance will be presented.

ARIEL e-LINAC: Commissioning and Development

International Nuclear Information System (INIS)

Laxdal, R.E.; Zvyagintsev, V.

2016-01-01

A superconducting electron Linac (e-Linac) will be a part of the ARIEL facility for the production of radioactive ion beams (RIB) at TRIUMF. The e-Linac will consist of five 1.3GHz 9-cell cavities in three cryomodules delivering a 50MeV 10mA beam. The baseline operation will be single pass but a re-circulating ring is planned to allow either energy boost or energy recovery operation. The first stage of the accelerator which consists of two cryomodules has been successfully commissioned in 2014. The paper will discuss the superconducting radio-frequency (SRF) challenges of the accelerator. Cavities, crymodules and RF system design, preparation, and performance will be presented. (paper)

RIA Superconducting Drift Tube Linac R and D

International Nuclear Information System (INIS)

Popielarski, J.; Bierwagen, J.; Bricker, S.; Compton, C.; DeLauter, J.; Glennon, P.; Grimm, T.; Hartung, W.; Harvell, D.; Hodek, M.; Johnson, M.; Marti, F.; Miller, P.; Moblo, A.; Norton, D.; Popielarski, L.; Wlodarczak, J.; York, R.C.; Zeller, A.

2009-01-01

Cavity and cryomodule development work for a superconducting ion linac has been underway for several years at the National Superconducting Cyclotron Laboratory. The original application of the work was the proposed Rare Isotope Accelerator. At present, the work is being continued for use with the Facility for Rare Isotope Beams (FRIB). The baseline linac for FRIB requires 4 types of superconducting cavities to cover the velocity range needed to accelerate an ion beam to (ge) 200 MeV/u: 2 types of quarter-wave resonator (QWR) and 2 types of half-wave resonator (HWR). Superconducting solenoids are used for focusing. Active and passive shielding is required to ensure that the solenoids field does not degrade the cavity performance. First prototypes of both QWR types and one HWR type have been fabricated and tested. A prototype solenoid has been procured and tested. A test cryomodule has been fabricated and tested. The test cryomodule contains one QWR, one HWR, one solenoid, and one super-ferric quadrupole. This report covers the design, fabrication, and testing of this cryomodule

Experience with a radio frequency gun on the SSRL Injector Linac

International Nuclear Information System (INIS)

Weaver, J.N.; Genin, R.D.; Golceff, P.; Morales, H.; Sebek, J.

1993-04-01

A-SSRL/Varian-Associates-built, one-and-a-half cavity microwave, thermionic-cathode gun has operated on the SSRL Injector Linac reliably without changing the cathode for over 10,000 hours, with no significant decrease in emission. Thus, for a pulsed electron beam, with a maximum of 0.5 A peak at 2 to 3 MeV from a 3.5 MW peak rf pulse of 2 μs pulse width at 10 pps, the apparent but small amount of back bombardment of the cathode has been tolerable. Use of a bunch-compression alpha magnet and a stripline chopper after the gun produces the required S-band 3 to 5 microbunches of electrons for injection into a standard 10-m-long linac and on into a booster synchrotron, which in turn is used to fill SPEAR. Component limitations and operating characteristics of the gun and the linac's rf system are discussed

Measurements of quadrupole frequency shift in the SPS at 26 GeV/c

CERN Document Server

Bohl, T; Shaposhnikova, E; Tückmantel, Joachim; CERN. Geneva. AB Department

2008-01-01

Measurements of the quadrupole frequency shift with intensity at 26 GeV/c using the peak detected signal were performed in the SPS from 1999 to monitor the evolution of the low-frequency longitudinal impedance [1]. While the large changes, first, due to the impedance reduction and then due to the re-installation of the MKE kickers,are easy to see, to observe small variations of impedance (as shielding or removal of a few kickers) much higher accuracy of measurements is required. This was difficult to achieve so far, mainly due to the insufficient reproducibility of the longitudinal parameters of the injected beam for different intensities as well as for different MDs. In this Note the important role of longitudinal emittance in addition to the bunch length is also revealed.

Induction Linac Systems Experiments for heavy ion fusion

International Nuclear Information System (INIS)

Herrmannsfeldt, W.B.; Bangerter, R.O.

1994-06-01

The Lawrence Berkeley Laboratory and the Lawrence Livermore National Laboratory propose to build at LBL the Induction Linac Systems Experiments (ILSE), the next logical step toward the eventual goal of a heavy ion induction accelerator powerful enough to implode or drive inertial confinement fusion targets. Though much smaller than a driver, ILSE will be at full driver scale in several important parameters. Nearly all accelerator components and beam manipulations required for a driver will be tested. It is expected that ILSE will be built in stages as funds and technical progress allow. The first stage, called Elise will include all of the electrostatic quadrupole focused parts of ILSE

Progress in the fabrication of the RFQ accelerator for the CERN Linac4

CERN Document Server

Rossi, C; Lallement, J B; Lombardi, A M; Mathot, S; Pugnat, D; Timmins, M; Vandoni, G; Vretenar, M; Desmons, M; France, A; Le Noa, Y; Novo, G; Piquet, O

2010-01-01

The construction of Linac4, the new 160 MeV CERN H- injector, has started with the goal of improving the LHC injection chain from 2015 with a new higher energy linac. The low energy front end of Linac4 is based on a 352 MHz, 3-m long Radiofrequency Quadrupole (RFQ) accelerator [1]. The RFQ accelerates the 70 mA, 45 keV H- beam from the RF source to the energy of 3 MeV. The fabrication of the RFQ has started at CERN in 2009 and is presently in progress, aiming at the completion of the full structure by early 2011. The RFQ consists of three modules, one meter each; the fabrication alternates machining phases and stress relief cycles, for copper stabilization. Two brazing steps are required: one to assemble the four parts composing a module, and a second one to install the stainless steel flanges. In order to monitor that the tight mechanical and alignment budget is not exceeded, metrology measurements at the CERN workshop and RF bead-pull measurements are performed during the fabrication process. In this paper ...

Linac technology for free-electron lasers

International Nuclear Information System (INIS)

Cooper, R.K.; Morton, P.L.; Wilson, P.B.; Keefe, D.; Faltens, A.

1983-01-01

The purpose of this paper is to concentrate on the properties of high-energy electron linear accelerators for use in free-electron lasers operating principally in the Compton regime. To fix our focus somewhat, we shall consider electron energies in the 20- to 200-MeV range and consider requirements for high-power free-electron lasers operating in the 0.5- to 10-μm range. Preliminary remarks are made on high-power free-electron laser amplifiers and oscillators and some desirable characteristics of the linacs that deliver electron beams for these devices. Both the high peak-current requirements of the amplifier and the high pulse-repetition frequency requirements of the oscillator can be met by present-day linac technology, although not necessarily by the same machine. In this papers second and third section, the technology of two rather different types of linear accelerators, the rf linac and the induction linac, is reviewed. In conclusion, applications to the Free Electron Lasers are stated

SRF LINAC for future extension of the PEFP

Energy Technology Data Exchange (ETDEWEB)

Kim, Han Sung; Kwon, Hyeok Jung; Seol, Kyoung Tae; Jang, Ji Ho; Cho, Yong Sub [Proton Engineering Frontier Project, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2014-04-15

A study on the superconducting RF linac is underway in order to increase the beam energy up to 1 GeV by extending the Proton Engineering Frontier Project (PEFP) 100-MeV linac. The operating frequency of the PEFP superconducting linac (SCL) is 700 MHz, which is determined by the fact that the frequency of the existing normal conducting linac is 350 MHz. A preliminary study on the beam dynamics showed that two types of cavities with geometrical betas of 0.50 and 0.74 could cover the entire energy range from 100 MeV to 1 GeV. An inductive output tube (IOT) based RF system is under consideration as a high-power RF source for the SCL due to its low operating voltage and high efficiency. As a prototyping activity for a reduced beta cavity, a five-cell cavity with a geometrical beta of 0.42 was designed and fabricated. A vertical test of the prototype cavity at low temperatures was performed to check the performance of the cavity. The design study and the prototyping activity for the PEFP SCL will be presented in this paper.

SRF LINAC for future extension of the PEFP

International Nuclear Information System (INIS)

Kim, Han Sung; Kwon, Hyeok Jung; Seol, Kyoung Tae; Jang, Ji Ho; Cho, Yong Sub

2014-01-01

A study on the superconducting RF linac is underway in order to increase the beam energy up to 1 GeV by extending the Proton Engineering Frontier Project (PEFP) 100-MeV linac. The operating frequency of the PEFP superconducting linac (SCL) is 700 MHz, which is determined by the fact that the frequency of the existing normal conducting linac is 350 MHz. A preliminary study on the beam dynamics showed that two types of cavities with geometrical betas of 0.50 and 0.74 could cover the entire energy range from 100 MeV to 1 GeV. An inductive output tube (IOT) based RF system is under consideration as a high-power RF source for the SCL due to its low operating voltage and high efficiency. As a prototyping activity for a reduced beta cavity, a five-cell cavity with a geometrical beta of 0.42 was designed and fabricated. A vertical test of the prototype cavity at low temperatures was performed to check the performance of the cavity. The design study and the prototyping activity for the PEFP SCL will be presented in this paper.

Adjustable Permanent Quadrupoles Using Rotating Magnet Material Rods for the Next Linear Collider

International Nuclear Information System (INIS)

Spencer, Cherrill M

2002-01-01

The proposed Next Linear Collider (NLC) will require over 1400 adjustable quadrupoles between the main linacs' accelerator structures. These 12.7 mm bore quadrupoles will have a range of integrated strength from 0.6 to 132 Tesla, with a maximum gradient of 135 Tesla per meter, an adjustment range of +0 -20% and effective lengths from 324 mm to 972 mm. The magnetic center must remain stable to within 1 micrometer during the 20% adjustment. In an effort to reduce estimated costs and increase reliability, several designs using hybrid permanent magnets have been developed. All magnets have iron poles and use either Samarium Cobalt or Neodymium Iron to provide the magnetic fields. Two prototypes use rotating rods containing permanent magnetic material to vary the gradient. Gradient changes of 20% and center shifts of less than 20 microns have been measured. These data are compared to an equivalent electromagnet prototype. See High Reliability Prototype Quadrupole for the Next Linear Collider by C.E Rago, C.M SPENCER, Z. Wolf submitted to this conference

Performance report on the ground test accelerator radio-frequency quadrupole

International Nuclear Information System (INIS)

Sander, O.R.; Atkins, W.H.; Bolme, G.O.; Brown, S.; Cole, R.; Connolly, R.; Gilpatrick, J.D.; Garnett, R.; Guy, F.W.; Ingalls, W.B.

1994-01-01

The Ground Test Accelerator (GTA) uses a radio-frequency quadrupole (RFQ) to bunch and accelerate a 35 keV input beam to a final energy of 2.5 MeV. Most measured parameters of the GTA RFQ agreed with simulated predictions. The relative shape of the transmission versus the vane-voltage relationship and the Courant-Snyder (CS) parameters of the output beam's transverse and longitudinal phase spaces agreed well with predictions. However, the transmission of the RFQ was significantly lower than expected. Improved simulation studies included image charges and multipole effects in the RFQ. Most of the predicted properties of the RFQ, such as input matched-beam conditions and output-beam shapes were unaffected by these additional effects. However, the comparison of measured with predicted absolute values of transmitted beam was much improved by the inclusion of these effects in the simulations. The comparison implied a value for the input emittance that is consistent with measurements

Argonne superconducting heavy-ion linac

International Nuclear Information System (INIS)

Bollinger, L.M.; Benaroya, R.; Clifft, B.E.; Jaffey, A.H.; Johnson, K.W.; Khoe, T.K.; Scheibelhut, C.H.; Shepard, K.W.; Wangler, Y.Z.

1976-01-01

A summary is given of the status of a project to develop and build a small superconducting linac to boost the energy of heavy ions from an existing tandem electrostatic accelerator. The design of the system is well advanced, and construction of major components is expected to start in late 1976. The linac will consist of independently-phased resonators of the split-ring type made of niobium and operating at a temperature of 4.2 0 K. The resonance frequency is 97 MHz. Tests on full-scale resonators lead one to expect accelerating fields of approximately 4 MV/m within the resonators. The linac will be long enough to provide a voltage gain of at least 13.5 MV, which will allow ions with A less than or approximately 80 to be accelerated above the Coulomb barrier of any target. The modular nature of the system will make future additions to the length relatively easy. A major design objective is to preserve the good quality of the tandem beam. This requires an exceedingly narrow beam pulse, which is achieved by bunching both before and after the tandem. Focusing by means of superconducting solenoids within the linac limit the radial size of the beam. An accelerating structure some 15 meters downstream from the linac will manipulate the longitudinal phase ellipse so as to provide the experimenter with either very good energy resolution (ΔE/E approximately equal to 2 x 10 -4 ) or very good time resolution

RF linac designs with beams in thermal equilibrium

International Nuclear Information System (INIS)

Reiser, M.; Brown, N.

1996-01-01

Beams in conventional radio-frequency linear accelerators (rf linacs) usually have a transverse temperature which is much larger than the longitudinal temperature. With high currents, space charge forces couple the transverse and longitudinal particle motions, driving the beam toward thermal equilibrium, which leads to emittance growth and halo formation. A design strategy is proposed in which the beam has equal transverse and longitudinal temperatures through the entire linac, avoiding these undesirable effects. For such equipartitioned linac beams, simple analytical relationships can be derived for the bunch size, tune depression, and other parameters as a function of beam intensity, emittance, and external focusing. These relations were used to develop three conceptual designs for a 938 MeV, 100 mA proton linac with different tune depressions, which are presented in this paper. copyright 1996 American Institute of Physics

Rf system description for the ground test accelerator radio-frequency quadrupole

International Nuclear Information System (INIS)

Regan, A.H.; Brittain, D.; Rees, D.E.; Ziomek, D.

1992-01-01

This paper describes the RF system being used to provide RF power and to control the cavity field used for the ground test accelerator (GTA) radio-frequency quadrupole (RFQ). The RF system consists of a low-level RF (LLRF) control system that uses a tetrode as a high-power amplifier (HPA) as part of its plant to deliver up to 300 kW of peak power to the RFQ at a 2% duty factor. The LLRF control system implements in-phase and quadrature (I ampersand Q) control to maintain the cavity field within tolerances of 0.5% in amplitude and 0.5 degrees in phase in the presence of beam-induced instabilities. This paper describes the identified components and presents measured performance data. The user interface with the systems is described, and cavity field measurements are included

Electron linacs

Energy Technology Data Exchange (ETDEWEB)

Loew, G A; Schriber, S O [ed.

1976-11-01

A study was made of the present status of the thousand or so electron linacs in the world, and future trends in the field. These machines were classified according to their use: medical, industrial, and nuclear physics. In the medical category, two types of electron linacs are discussed: the conventional ones which are used for x-ray and electron therapy, and those which may in the future be used for negative pion therapy. Industrial machines discussed include linacs for radiographic and other specialized applications. In the nuclear physics category, the status of conventional low- and medium-energy as well as high duty cycle linacs is reviewed. The question of how one might obtain a c-w, 1 GeV, 100..mu..A electron linac is raised, and various options using recirculation and stretchers are examined. In this connection, the status of rf superconductivity is summarized. A review is given of linacs for injectors into synchrotrons and e/sup +-/ storage rings, and recent work done to upgrade the only multi-GeV linac, namely SLAC, is described.

Electron linacs

International Nuclear Information System (INIS)

Loew, G.A.

1976-01-01

To study the present status of the thousand or so electron linacs in the world, and future trends in the field, we have classified these machines according to their use: medical, industrial, and nuclear physics. In the medical category, two types of electron linacs are discussed: the conventional ones which are used for X-ray and electron therapy, and those which may in the future be used for negative pion therapy. The section on industrial machines includes linacs for radiographic and other specialized applications. In the nuclear physics category, the status of conventional low- and medium-energy as well as high duty cycle linacs is reviewed. The question of how one might obtain a C.W., 1 GeV, 100 μA electron linac is raised and various options using recirculation and stretchers are examined. In this connection, the status of RF superconductivity is summarized. Following, there is a review of linacs for injectors into synchrotrons and e +- storage rings. The paper ends with a description of recent work done to upgrade the only multi-GeV linac, namely SLAC. (author)

Low-beam-loss design of a compact, high-current deuteron radio frequency quadrupole accelerator

Directory of Open Access Journals (Sweden)

C. Zhang

2004-10-01

Full Text Available A 201.5 MHz, 50 mA, 2.0 MeV deuteron radio frequency quadrupole accelerator is proposed as the neutron generator for the neutron experiment facility project at Peking University, China. Based on better understanding of beam losses, some new optimization procedures concerning both longitudinal and transverse dynamics are adopted. Accordingly, the beam transmission efficiency is improved from 91.2% to 98.3% and the electrode length is shortened from 2.91 to 2.71 m. The fundamental physical analyses are performed to look inside the new design recipe and explain why it works.

Design of permanent magnet quadrupole for LEHIPA DTL

International Nuclear Information System (INIS)

Mathew, Jose V.; Rao, S.V.L.S.; Krishnagopal, S.; Singh, P.

2011-01-01

The drift tube linac (DTL) of the low energy high intensity proton accelerator (LEHIPA) has been designed to accelerate 30 mA proton beam from 3 MeV to 20 MeV in a distance of around 13 m. A FFDD lattice structure is selected to provide strong transverse focusing, where each drift tube includes one quadrupole magnet. Beam dynamics simulations specified an effective magnet length of 47 mm, maximum field gradient of 47 T/m, and bore aperture of 24 mm. For these specifications, a detailed design of a very thin permanent magnet quadrupole (PMQ) is presented. Four types of PMQ designs have been compared: a 16-segment trapezoidal design in the Halbach configuration, two 16-segment rectangular designs (with and without gaps), and an 8-segment rectangular design. 2D and 3D modeling codes, POISSON and CST Studio suite are used for the design studies. The good field region is calculated based on field gradient deviation in the transverse plane and integral field homogeneity. The very low aspect ratio of these PMQs leads to edge effects, thereby reducing the central field strength. The 3D simulations are used to study these edge effects. (author)

Reduction of losses in linacs for protons or heavy ions

International Nuclear Information System (INIS)

Claus, J.

1977-01-01

It is necessary to minimize the beam losses in linacs for high average currents in order to avoid serious problems due to radiation damage, dissipation and radio activation of the accelerator structure. A large part of the losses in existing linacs is due to incomplete bunching of the injected beam. Proposed improvements generally appear to be deficient in one or more respects if applied to linacs with conventional frequencies, injection energies and current densities. By preceding the linac proper with an accelerating structure and an energy analyzer, it becomes possible to separate the particles that remained outside the buckets from those that are inside so that they can be dumped in a controlled manner

Radio-frequency quadrupole resonator for linear accelerator

Science.gov (United States)

Moretti, A.

1982-10-19

An RFQ resonator for a linear accelerator having a reduced level of interfering modes and producing a quadrupole mode for focusing, bunching and accelerating beams of heavy charged particles, with the construction being characterized by four elongated resonating rods within a cylinder with the rods being alternately shorted and open electrically to the shell at common ends of the rods to provide an LC parallel resonant circuit when activated by a magnetic field transverse to the longitudinal axis.

Radio frequency quadrupole resonator for linear accelerator

Science.gov (United States)

Moretti, Alfred

1985-01-01

An RFQ resonator for a linear accelerator having a reduced level of interfering modes and producing a quadrupole mode for focusing, bunching and accelerating beams of heavy charged particles, with the construction being characterized by four elongated resonating rods within a cylinder with the rods being alternately shorted and open electrically to the shell at common ends of the rods to provide an LC parallel resonant circuit when activated by a magnetic field transverse to the longitudinal axis.

The RF system for the 70 MeV linac injector

International Nuclear Information System (INIS)

Planner, C.W.

1975-12-01

The Radio Frequency System for the 70 MeV Linac Injector for Nimrod is required to power the four Accelerating Cavities and the Buncher and Debuncher Cavities. The frequency of operation is 202.5 MHz and is determined by the use of existing equipment from the redundant 50 MeV Proton Linac for the second and third accelerating cavities and the buncher and de-buncher cavities. The subject is discussed under the following headings: low power drive chain; RF feed lines; cavity field level stabilisation. Circuit diagrams are presented. (U.K.)

Klystron High Power Operation for KOMAC 100-MeV Proton Linac

Energy Technology Data Exchange (ETDEWEB)

Seol, Kyung-Tae; Kim, Seong-Gu; Kwon, Hyeok-Jung; Kim, Han-Sung; Cho, Yong-Sub [KAERI, Daejeon (Korea, Republic of)

2015-05-15

The Korea multi-purpose accelerator complex (KOMAC) accelerator facility has a 100-MeV proton linac, five beam lines for 20-MeV beam utilization, and another five beam lines for 100-MeV beam utilization. The 100-MeV linac consists of a 50-keV proton injector based on a microwave ion source, a 3-MeV RFQ with a four-vane structure, and a 100-MeV DTL. Nine sets of 1MW klystrons have been operated for the 100-MeV proton linac. The klystron filament heating time was approximately 5700 hours in 2014, and RF operation time was 2863.4 hours. During the high power operation of the klystron, unstable RF waveforms appeared at the klystron output, and we have checked and performed cavity frequency adjustments, magnet and heater current, reflection from a circulator, klystron test without a circulator, and the frequency spectrum measurement. Nine sets of the klystrons have been operated for the KOMAC 100-MeV proton linac. The klystron filament heating time was 5700 hours and RF operation time was 2863.4 hours during the operation in 2014. Some klystrons have unstable RF waveforms at specific power level. We have checked and tested the cavity frequency adjustment, reflection from a circulator, high power test without a circulator, and frequency spectrum at the unstable RF.

Argonne superconducting heavy-ion linac

Energy Technology Data Exchange (ETDEWEB)

Bollinger, L.M.; Benaroya, R.; Clifft, B.E.; Jaffey, A.H.; Johnson, K.W.; Khoe, T.K.; Scheibelhut, C.H.; Shepard, K.W.; Wangler, Y.Z.

1976-01-01

A summary is given of the status of a project to develop and build a small superconducting linac to boost the energy of heavy ions from an existing tandem electrostatic accelerator. The design of the system is well advanced, and construction of major components is expected to start in late 1976. The linac will consist of independently-phased resonators of the split-ring type made of niobium and operating at a temperature of 4.2/sup 0/K. The resonance frequency is 97 MHz. Tests on full-scale resonators lead one to expect accelerating fields of approximately 4 MV/m within the resonators. The linac will be long enough to provide a voltage gain of at least 13.5 MV, which will allow ions with A less than or approximately 80 to be accelerated above the Coulomb barrier of any target. The modular nature of the system will make future additions to the length relatively easy. A major design objective is to preserve the good quality of the tandem beam. This requires an exceedingly narrow beam pulse, which is achieved by bunching both before and after the tandem. Focusing by means of superconducting solenoids within the linac limit the radial size of the beam. An accelerating structure some 15 meters downstream from the linac will manipulate the longitudinal phase ellipse so as to provide the experimenter with either very good energy resolution (..delta..E/E approximately equal to 2 x 10/sup -4/) or very good time resolution (..delta.. t approximately equal to 30 psec).

Detuning effect in a traveling wave type linac

International Nuclear Information System (INIS)

Arai, S.; Kobayashi, K.; Tojyo, E.; Yoshida, K.

1979-01-01

A 15-MeV traveling wave type electron linac is used as the injector for the 1.3-GeV electron synchrotron at the Institute for Nuclear Study, University of Tokyo. The resonant frequency of this accelerator waveguide is 2758.00 MHz at 30 0 C. The performance of the linac,however, is improved when it is operated with a frequency which is higher than the design value by 200 to 400 KHz. It is shown that the detuning due to the beam loading is serious in such an accelerator waveguide in which the buncher and regular sections are combined, and the detuning effect can approximately be compensated by changing the operating frequency. The detuning effect in the traveling wave-type accelerator waveguide was studied both from experimental and theoretical aspects by using a short test waveguide

Design and Development of RF Structures for Linac4

CERN Document Server

Vretenar, M; Gerigk, F; Pasini, M; Wegner, R

2006-01-01

Linac4 is a new 160 MeV H− linac proposed at CERN to replace the 50 MeV Linac2 as injector to the PS Booster, with the goal of doubling its brightness and intensity. The present design foresees after RFQ and chopping line a sequence of three accelerating structures: a Drift Tube Linac (DTL) from 3 to 40 MeV, a Cell-Coupled DTL (CCDTL) to 90 MeV and a Side Coupled Linac (SCL) up to the final energy. The DTL and CCDTL operate at 352 MHz, while in the SCL the frequency is doubled to 704 MHz. Although the injection in the PS Booster requires only a low duty cycle, the accelerating structures are designed to operate at the high duty cycle required by a possible future extension to a high-power linac driver for a neutrino facility. This paper presents the different accelerating structures, underlining the progress in the design of critical resonator elements, like post-couplers in the DTL, coupling slots in the CCDTL and bridge couplers for the SCL. Prototyping progress for the different structures is reported...

Auto-tuning systems for J-PARC LINAC RF cavities

International Nuclear Information System (INIS)

Fang, Z.; Kobayashi, T.; Fukui, Y.; Futatsukawa, K.; Michizono, S.; Yamaguchi, S.; Anami, S.; Suzuki, H.; Sato, F.; Shinozaki, S.; Chishiro, E.

2014-01-01

The 400-MeV proton linear accelerator (LINAC) at the Japan Proton Accelerator Research Complex (J-PARC) consists of 324-MHz low-β and 972-MHz high-β accelerator sections. From October 2006 to May 2013, only the 324-MHz low-β accelerator section was in operation. From the summer of 2013 the J-PARC LINAC was upgraded by installing the 972-MHz high-β accelerator section, and the proton beam was successfully accelerated to 400 MeV in January 2014. Auto-tuning systems for the J-PARC LINAC RF cavities have been successfully developed. A first generation design, an auto-tuning system using a mechanical tuner controller, was developed and operated for the first 3 years. Then the second-generation auto-tuning system was developed using a new approach to the RF cavity warm-up process, and this was applied to the accelerator operation for the subsequent 4 years. During the RF cavity warm-up process in this system, the mechanical tuner is constantly fixed and the input RF frequency is automatically tuned to the cavity resonance frequency using the FPGA (Field-Programmable Gate Array) of the digital feedback RF control system. After the input power level reaches the required value, input RF frequency tuning is stopped and it is switched to the operation frequency. Then, the mechanical tuner control begins operation. This second-generation auto-tuning system was extremely effective for the 324-MHz cavity operation. However, if we apply this approach to the 972-MHz RF cavities, an interlock due to the RF cavity reflection amplitude occasionally occurs at the end of the warm-up process. In order to solve this problem a third generation novel auto-tuning system was successfully developed in December 2013 and applied to the operation of the J-PARC LINAC, including the 972-MHz ACS RF cavities. During the warm-up process both the mechanical tuner controller and the input RF frequency tuning are in operation, and good matching between the input RF frequency and the RF cavity is

Auto-tuning systems for J-PARC LINAC RF cavities

Energy Technology Data Exchange (ETDEWEB)

Fang, Z., E-mail: fang@post.kek.jp [High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Kobayashi, T.; Fukui, Y.; Futatsukawa, K.; Michizono, S.; Yamaguchi, S.; Anami, S. [High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Suzuki, H.; Sato, F.; Shinozaki, S.; Chishiro, E. [Japan Atomic Energy Agency (JAEA), 2-4 Shirane Shirakata, Tokai-mura, Naka-gun, Ibaraki 319-1195 (Japan)

2014-12-11

The 400-MeV proton linear accelerator (LINAC) at the Japan Proton Accelerator Research Complex (J-PARC) consists of 324-MHz low-β and 972-MHz high-β accelerator sections. From October 2006 to May 2013, only the 324-MHz low-β accelerator section was in operation. From the summer of 2013 the J-PARC LINAC was upgraded by installing the 972-MHz high-β accelerator section, and the proton beam was successfully accelerated to 400 MeV in January 2014. Auto-tuning systems for the J-PARC LINAC RF cavities have been successfully developed. A first generation design, an auto-tuning system using a mechanical tuner controller, was developed and operated for the first 3 years. Then the second-generation auto-tuning system was developed using a new approach to the RF cavity warm-up process, and this was applied to the accelerator operation for the subsequent 4 years. During the RF cavity warm-up process in this system, the mechanical tuner is constantly fixed and the input RF frequency is automatically tuned to the cavity resonance frequency using the FPGA (Field-Programmable Gate Array) of the digital feedback RF control system. After the input power level reaches the required value, input RF frequency tuning is stopped and it is switched to the operation frequency. Then, the mechanical tuner control begins operation. This second-generation auto-tuning system was extremely effective for the 324-MHz cavity operation. However, if we apply this approach to the 972-MHz RF cavities, an interlock due to the RF cavity reflection amplitude occasionally occurs at the end of the warm-up process. In order to solve this problem a third generation novel auto-tuning system was successfully developed in December 2013 and applied to the operation of the J-PARC LINAC, including the 972-MHz ACS RF cavities. During the warm-up process both the mechanical tuner controller and the input RF frequency tuning are in operation, and good matching between the input RF frequency and the RF cavity is

Rfq With An Increased Energy Gain

CERN Document Server

Kapin, Valery

2004-01-01

The radio-frequency quadrupole (RFQ) linacs are widely used in the initial part of ion accelerators. For industrial and medical applications, the size of RFQ linac as well as the construction and operation costs are important. Therefore, there is a interest to design a compact RFQ linac. In this paper, RFQ linac is studied with the aim of increasing the energy gain. Parameters of a conventional RFQ linac are usually chosen to ensure beam acceleration and stability, providing the autophasing and strong quadrupole focusing in the longitudinal and transverse directions simultaneously. As results, the accelerating efficiency of RFQ is limited by the transverse defocusing effect, and its value is below of a maximum value, which can be provided by RFQ electrodes. To facilitate these limitations, the well-known idea of alternating phase focusing (APF) is utilized. The APF effects boost transverse focusing, allowing to increase an accelerating efficiency, electrode voltage and decreasing average value of the synchron...

Dynamic imperfections and optimized feedback design in the Compact Linear Collider main linac

CERN Document Server

Eliasson, Peder

2008-01-01

The Compact Linear Collider (CLIC) main linac is sensitive to dynamic imperfections such as element jitter, injected beam jitter, and ground motion. These effects cause emittance growth that, in case of ground motion, has to be counteracted by a trajectory feedback system. The feedback system itself will, due to jitter effects and imperfect beam position monitors (BPMs), indirectly cause emittance growth. Fast and accurate simulations of both the direct and indirect effects are desirable, but due to the many elements of the CLIC main linac, simulations may become very time consuming. In this paper, an efficient way of simulating linear (or nearly linear) dynamic effects is described. The method is also shown to facilitate the analytic determination of emittance growth caused by the different dynamic imperfections while using a trajectory feedback system. Emittance growth expressions are derived for quadrupole, accelerating structure, and beam jitter, for ground motion, and for noise in the feedback BPMs. Fina...

A new matcher type between RFQ and IH-DTL for the GSI high current heavy ion prestripper linac

International Nuclear Information System (INIS)

Ratzinger, U.; Tiede, R.

1996-01-01

The adaptation of a RFQ beam to the typical requirements at the entrance of a drift tube linac is rather difficult at high intensities and high A/q values. The high focusing power needed for such a matcher can be provided by a conventional array with rather large quadrupoles and rebuncher cavities only. Many problems arising from such a design can be avoided by using an element which is focusing in transverse and longitudinal direction at the same time, that is a short RFQ ('Super Lens') with 10 cells typically and a larger aperture as compared to the main RFQ. A xy-steerer and a short quadrupole doublet with small aperture were added to gain flexibility with regard to beam mismatch and misalignment corrections. This new concept is realised for the GSI 15 mA U 4+ injector, which is under construction. Beam dynamics calculations are presented and compared with results for a conventional solution consisting of a rebuncher and a quadrupole triplet. (author)

Effect of high current electron beam in a 30 MeV radio frequency linac for neutron-time-of-flight applications

Energy Technology Data Exchange (ETDEWEB)

Nayak, B., E-mail: biswaranjan.nayak1@gmail.com; Acharya, S.; Rajawat, R. K. [Accelerator and Pulsed Power Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); DasGupta, K. [Accelerator and Pulsed Power Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Beam Technology Development Group, BARC, Mumbai 400085 (India)

2016-01-15

A high power pulsed radio frequency electron linac is designed by BARC, India to accelerate 30 MeV, 10 A, 10 ns beam for neutron-time-of-flight applications. It will be used as a neutron generator and will produce ∼10{sup 12}–10{sup 13} n/s. It is essential to reduce the beam instability caused by space charge effect and the beam cavity interaction. In this paper, the wakefield losses in the accelerating section due to bunch of RMS (Root mean square) length 2 mm (at the gun exit) is analysed. Loss and kick factors are numerically calculated using CST wakefield solver. Both the longitudinal and transverse wake potentials are incorporated in beam dynamics code ELEGANT to find the transverse emittance growth of the beam propagating through the linac. Beam loading effect is examined by means of numerical computation carried out in ASTRA code. Beam break up start current has been estimated at the end of the linac which arises due to deflecting modes excited by the high current beam. At the end, transverse beam dynamics of such high current beam has been analysed.

Induction linacs

International Nuclear Information System (INIS)

Keefe, D.

1986-07-01

The principle of linear induction acceleration is described, and examples are given of practical configurations for induction linacs. These examples include the Advanced Technology Accelerator, Long Pulse Induction Linac, Radial Line Accelerator (RADLAC), and Magnetically-Insulated Electron-Focussed Ion Linac. A related concept, the auto accelerator, is described in which the high-current electron-beam technology in the sub-10 MeV region is exploited to produce electron beams at energies perhaps as high as the 100 to 1000 MeV range. Induction linacs for ions are also discussed. The efficiency of induction linear acceleration is analyzed

On the choice of the adjusting mouth electrode profile at the input of a linear accelerator with space-uniform quadrupole focusing

International Nuclear Information System (INIS)

Balabin, A.I.; Kapchinskij, I.M.; Lipkin, I.M.

1983-01-01

Beam matching of an electrostatical injector with a linear accelerator is an important problem, since acceptance at the inlet of a linac with space-homogeneous quadrupole focusing (SHQF) does not remain constant but rotates with the frequency of an accelerating field. A possibility of transverse stationary beam matching with the SHQF at the inlet of the linac can be ensured to a considerable extent by means of an initial matching section (matching mouth) at the length of which focusing hardness varies according to a certain law. In this case the purpose of creating beam matching conditions practically independent of the phases of particles at the inlet into the mouth is attained. Transverse beam matching for different laws of focusing hardness variation along the non-modulated mouth is investigated. It is shown that for earlier suggested laws of hardness variation the matching conditions at the mouth inlet are critically dependent on the input phases of particles at high phase densities of the beam current j. Laws of hardness variation ensuring actual matching condition independence of the phases of particles up to j=2 A/cmxmrad (for protons) are suggested. A case of beam matching by means of the modulated mouth is also considered. Recommendations on mouth modulation laws are given

Stabilization of the RF system at the SPring-8 linac

CERN Document Server

Asaka, T; Hori, T; Kobayashi, T; Mizuno, A; Sakaki, H; Suzuki, S; Taniuchi, T; Yanagida, K; Yokomizo, H; Yoshikawa, H

2002-01-01

Beam energy variation of the SPring-8 linac was 1% or more at the start of beam commissioning. Depending on fluctuation, beam transmission efficiency from the linac to the booster synchrotron was significantly affected, and beam intensity in the booster synchrotron changed 20-30%. This caused delay of optimization of the various parameters in the booster synchrotron. More problematic, the beam intensities stored in each RF (radio frequency) bucket of the storage ring at SPring-8 were all different from each other. The users utilizing synchrotron radiation requested that the beam intensity in each RF bucket be as uniform as possible. It was thus a pressing necessity to stabilize the beam energy in the linac. Investigation of the cause has clarified that the various apparatuses installed in the linac periodically changed depending on circumstances and utilities such as the air conditioner, cooling water and electric power. After various improvements, beam energy stability in the linac of <0.06% rms was attai...

Design study of high gradient, low impedance accelerating structures for the FERMI free electron laser linac upgrade

Science.gov (United States)

Shafqat, N.; Di Mitri, S.; Serpico, C.; Nicastro, S.

2017-09-01

The FERMI free-electron laser (FEL) of Elettra Sincrotrone Trieste, Italy, is a user facility driven by a 1.5 GeV 10-50 Hz S-band radiofrequency linear accelerator (linac), and it is based on an external laser seeding scheme that allows lasing at the shortest fundamental wavelength of 4 nm. An increase of the beam energy to 1.8 GeV at a tolerable breakdown rate, and an improvement of the final beam quality is desired in order to allow either lasing at 4 nm with a higher flux, or lasing at shorter wavelengths. This article presents the impedance analysis of newly designed S-band accelerating structures, for replacement of the existing backward travelling wave structures (BTWS) in the last portion of the FERMI linac. The new structure design promises higher accelerating gradient and lower impedance than those of the existing BTWS. Particle tracking simulations show that, with the linac upgrade, the beam relative energy spread, its linear and nonlinear z-correlation internal to the bunch, and the beam transverse emittances can be made smaller than the ones in the present configuration, with expected advantage to the FEL performance. The repercussion of the upgrade on the linac quadrupole magnets setting, for a pre-determined electron beam optics, is also considered.

Physics design of a 10 MeV, 6 kW travelling wave electron linac for ...

Indian Academy of Sciences (India)

2016-10-11

Oct 11, 2016 ... We present the physics design of a 10 MeV, 6 kW S-band (2856 MHz) electron linear ... linac (in contrast with standing wave linac) is that it accepts the RF power over a band of frequencies. Three- ... structures are preferred for relatively higher energy ... klystron in a TW linac, which results in cost reduction.

Design study of a medical proton linac for neutron therapy

International Nuclear Information System (INIS)

Machida, S.; Raparia, D.

1988-01-01

This paper describes a design study which establishes the physical parameters of the low energy beam transport, radiofrequency quadrupole, and linac, using computer programs available at Fermilab. Beam dynamics studies verify that the desired beam parameters can be achieved. The machine described here meets the aforementioned requirements and can be built using existing technology. Also discussed are other technically feasible options which could be attractive to clinicians, though they would complicate the design of the machine and increase construction costs. One of these options would allow the machine to deliver 2.3 MeV protons to produce epithermal neutrons for treating brain tumors. A second option would provide 15 MeV protons for isotope production. 21 refs., 33 figs

Nuclear quadrupole interactions in ferroelectric compounds of HF181

International Nuclear Information System (INIS)

Kunzler, J.V.

1971-01-01

Measurements of nuclear quadrupole interaction constants in perovkite-type compounds of PbHfO 3 , SnhfO 3 , CaHfO 3 e SrHfO 3 have been performed using the perturbed angular correlation technique. A range of fundamental frequencies from 150 to 550 Megaradians persecond was determined. The variation of quadrupole constants has been discussed through the molecular orbital theory

Injection schemes for the TOP Linac; Schemi di iniezione per il TOP Linac

Energy Technology Data Exchange (ETDEWEB)

Picardi, L.; Ronsivalle, C. [ENEA, Centro Ricerche Frascati, Frascati, RM (Italy). Dipt. Innovazione; Bartolini, R. [Istituto Superiore di Sanita' , Rome (Italy)

1999-07-01

In this report two schemes are studied for the injection in the SCDTL section of the TOP Linac of the proton beam produced by a 7 MeV linear accelerator. The project derives by an agreement between ENEA (National Agency for New Technology, Energy and Environment) and ISS. In these new versions of the design the constraint of a synchronization of the radio frequencies of the two accelerators is suppressed. [Italian] In questo rapporto sono studiati due schemi di iniezione nella sezione accelerante SCDTL a 3 GHz del TOP (terapia oncologica con protoni) linac del fascio di protoni generato da un acceleratore lineare di 7 MeV. L'acceleratore e' frutto di una convenzione tra L'ENEA e l'Istituto Superiore di Sanita'. Rispetto a versioni precedenti del progetto, viene eliminato il vincolo della sincronizzazione delle radiofrequenze dei due acceleratori.

HOM Dampers or not in Superconducting RF Proton Linacs

CERN Document Server

Tückmantel, Joachim

2009-01-01

Circular machines are plagued by Coupled Bunch Instabilities, driven by impedance peaks, irrespectively of their frequency relation to machine lines; hence all cavity Higher Order Modes are possible drivers. This is the fundamental reason that all superconducting RF cavities in circular machines are equipped with HOM dampers. This raises the question if HOM damping would not be imperative also in high current proton linacs where a mechanism akin to CBI might exist. To clarify this question we have simulated the longitudinal bunched beam dynamics in linacs, allowing bunch-to-bunch variations in time-of-arrival. Simulations were executed for a generic proton linac with properties close to SNS or the planned SPL at CERN. It was found that for monopole HOMs with high Qext large beam scatter or even beam loss cannot be excluded. Therefore omitting HOM dampers on superconducting RF cavities in high current proton linacs, even pulsed ones, is a very risky decision.

HOM Dampers or not in SUPERCONDUCTING RF Proton Linacs

CERN Document Server

Tückmantel, Joachim

2009-01-01

Circular machines are plagued by Coupled Bunch Instabilities, driven by impedance peaks, irrespectively of their frequency relation to machine lines; hence all cavity Higher Order Modes are possible drivers. This is the fundamental reason that all superconducting RF cavities in circular machines are equipped with HOM dampers. This raises the question if HOM damping would not be imperative also in high current proton linacs where a mechanism akin to CBI might exist. To clarify this question we have simulated the longitudinal bunched beam dynamics in linacs, allowing bunch-to-bunch variations in time-of-arrival. Simulations were executed for a generic proton linac with properties close to SNS or the planned SPL at CERN. It was found that for monopole HOMs with high Qext large beam scatter or even beam loss cannot be excluded. Therefore omitting HOM dampers on superconducting RF cavities in high current proton linacs, even pulsed ones, is a very risky decision.

Use of phase information with a stepper motor to control frequency for tuning system of the Front End Test Stand Radio Frequency Quadrupole at Rutherford Appleton Laboratory

Energy Technology Data Exchange (ETDEWEB)

Alsari, S., E-mail: s.alsari@imperial.ac.uk; Aslaninejad, M.; Pozimski, J.

2015-03-01

For the Front End Test Stand (FETS) linear accelerator project at the Rutherford Appleton Laboratory in the UK, a 4 m, 4 vanes Radio Frequency Quadrupole (RFQ) with a resonant frequency of 324 MHz has been designed. The RF power feeding the RFQ gives rise to the temperature increase in the RFQ, which in turn, results in shifting the resonant frequency of the RFQ. The frequency shift and the stability in the RFQ frequency can be maintained based on the reflected power or signal phase information. We have, however, investigated restoration of the RFQ nominal frequency based on the RF signal phases driving a stepper motor. The concept and the system set-up and electronics are described in detail. Results of the measurements indicating the full restoration of the RFQ nominal frequency based on the RF signal phases and stepper motor are presented. Moreover, measured sensitivity of tuner with respect to its position is given.

Use of phase information with a stepper motor to control frequency for tuning system of the Front End Test Stand Radio Frequency Quadrupole at Rutherford Appleton Laboratory

International Nuclear Information System (INIS)

Alsari, S.; Aslaninejad, M.; Pozimski, J.

2015-01-01

For the Front End Test Stand (FETS) linear accelerator project at the Rutherford Appleton Laboratory in the UK, a 4 m, 4 vanes Radio Frequency Quadrupole (RFQ) with a resonant frequency of 324 MHz has been designed. The RF power feeding the RFQ gives rise to the temperature increase in the RFQ, which in turn, results in shifting the resonant frequency of the RFQ. The frequency shift and the stability in the RFQ frequency can be maintained based on the reflected power or signal phase information. We have, however, investigated restoration of the RFQ nominal frequency based on the RF signal phases driving a stepper motor. The concept and the system set-up and electronics are described in detail. Results of the measurements indicating the full restoration of the RFQ nominal frequency based on the RF signal phases and stepper motor are presented. Moreover, measured sensitivity of tuner with respect to its position is given

Space-charge limits in linear accelerators

International Nuclear Information System (INIS)

Wangler, T.P.

1980-12-01

This report presents equations that allow an approximate evaluation of the limiting beam current for a large class of radio-frequency linear accelerators, which use quadrupole strong focusing. Included are the Alvarez, the Wideroe, and the radio-frequency quadrupole linacs. The limiting-current formulas are presented for both the longitudinal and the transverse degrees of freedom by assuming that the average space-charge force in the beam bunch arises from a uniformly distributed charge within an azimuthally symmetric three-dimensional ellipsoid. The Mathieu equation is obtained as an approximate, but general, form for the transverse equation of motion. The smooth-approximation method is used to obtain a solution and an expression for the transverse current limit. The form of the current-limit formulas for different linac constraints is discussed

Boson models of quadrupole collective motion

International Nuclear Information System (INIS)

Zelevinskij, V.G.

1985-01-01

The subject of the lecture is the low-lying excitations of even-even (e-e) spherical nuclei. The predominant role of the quadrupole mode, which determines the structure of spectra and transitions, is obvious on the background of shell periodicity and pair correlations. Typical E2-transitions are strengthened Ω ∼ A 2/3 times in comparison with single particle evaluations. Together with the regularity of the whole picture it gives evidence about collectivization of quadrupole motion. The collective states are combined in bands, where the transition probability are especially great; frequencies ω of the strengthened transitions are small in comparison with pair separation energies of 2 E-bar ∼ 2 MeV. Thus, the description of low-lying excitations of spherical nuclei has to be based on three principles: collectivity (Ω >> 1), adiabaticity (τ ≡ ω/2E-bar << 1) and quadrupole symmetry

Lead/tin resonator development at the Stony Brook heavy-ion linac

International Nuclear Information System (INIS)

Sikora, J.; Ben-Zvi, I.; Brennan, J.M.; Cole, M.; Noe, J.W.

1988-01-01

The Stony Brook Nuclear Structure Laboratory (NSL) has operated a superconducting heavy-ion booster linac since April 1983. The 40 copper split-loop resonators were developed and fabricated at Cal-Tech and plated with lead at Stony Brook. These original lead surfaces have given stable performance for the last 4 years, at an average accelerating gradient of about 2.5 MV/m in the high-β section. The low-β resonators however have never run reliably on-line much better than 2.0 MV/m, due to excessive vibration of their rather soft loop arms in the working accelerator environment. For the last 2-3 years the efforts of the Stony Brook accelerator development group have been focused on (1) a retrofit of the low-beta section of the linac with new QWRs and (2) the further development of plated superconducting surfaces. In particular a Sn/Pb alloy has been shown to give resonator performance at least comparable to that obtained with pure Pb but with a greatly simplified plating technique, as discussed below. Recently a possible heavy-ion injector based on superconducting RF quadrupole (RFQ) structures has also been studied. 13 references, 3 figures, 1 table

Cumulative beam break-up study of the spallation neutron source superconducting linac

CERN Document Server

Jeon, D; Krafft, G A; Yunn, B; Sundelin, R; Delayen, J; Kim, S; Doleans, M

2002-01-01

Beam instabilities due to High Order Modes (HOMs) are a concern to superconducting (SC) linacs such as the Spallation Neutron Source (SNS) linac. The effects of pulsed mode operation on transverse and longitudinal beam breakup instability are studied for H sup - beam in a consistent manner for the first time. Numerical simulation indicates that cumulative transverse beam breakup instabilities are not a concern in the SNS SC linac, primarily due to the heavy mass of H sup - beam and the HOM frequency spread resulting from manufacturing tolerances. As little as +-0.1 MHz HOM frequency spread stabilizes all the instabilities from both transverse HOMs, and also acts to stabilize the longitudinal HOMs. Such an assumed frequency spread of +-0.1 MHz HOM is small, and hence conservative compared with measured values of sigma=0.00109(f sub H sub O sub M -f sub 0)/f sub 0 obtained from Cornell and the Jefferson Lab Free Electron Laser cavities. However, a few cavities may hit resonance lines and generate a high heat lo...

Electromagnetic design issues in elliptic superconducting radio frequency cavity for H- LINAC

International Nuclear Information System (INIS)

Kumar, V.; Jana, A.R.; Gaur, R.

2013-01-01

Multi-cell elliptic superconducting radiofrequency (SCRF) cavities are used for efficient acceleration of a high power charged particle beam for a wide range of velocities, typically corresponding to β = 0.5 to ∼ 1, where β is the particle speed in unit of speed of light. Electromagnetic design of such cavities involves careful optimization of the cavity geometry with several design constraints. In this paper, we discuss a generalized approach to optimize the design to achieve maximum acceleration gradient and field flatness, while ensuring that the effect due to higher order modes supported by the cavity are within acceptable limits. Study of detuning in the cavity resonance frequency due to mechanical pressure associated with electromagnetic field inside the cavity, known as Lorentz Force Detuning (LFD), plays an important role in optimizing the scheme for stiffening of the cavity. Electromagnetic design calculations performed for SCRF cavities of medium energy section of 1 GeV H - injector linac for the proposed Indian Spallation Neutron Source (ISNS) at Raja Ramanna Centre for Advanced Technology are presented in the paper highlighting all these important design issues. (author)

Superconducting linac

International Nuclear Information System (INIS)

Bollinger, L.M.; Shepard, K.W.; Wangler, T.P.

1978-01-01

This project has two goals: to design, build, and test a small superconducting linac to serve as an energy booster for heavy ions from an FN tandem electrostatic accelerator, and to investigate various aspects of superconducting rf technology. The main design features of the booster are described, a status report on various components (resonators, rf control system, linac control system, cryostats, buncher) is given, and plans for the near future are outlined. Investigations of superconducting-linac technology concern studies on materials and fabrication techniques, resonator diagnostic techniques, rf-phase control, beam dynamics computer programs, asymmetry in accelerating field, and surface-treatment techniques. The overall layout of the to-be-proposed ATLAS, the Argonne Tandem-Linac Accelerator System, is shown; the ATLAS would use superconducting technology to produce beams of 5 to 25 MeV/A. 6 figures

Practical test of the LINAC4 RF power system

CERN Document Server

Schwerg, N

2011-01-01

The high RF power for the Linac4 accelerating structures will be generated by thirteen 1.3 MW klystrons, previously used for the CERN LEP accelerator, and six new klystrons of 2.8 MW all operating at a frequency of 352.2 MHz. The power distribution scheme features a folded magic tee feeding the power from one 2.8 MW klystron to two LEP circulators. We present first results from the Linac4 test place, validating the approach and the used components as well as reporting on the klystron re-tuning activities.

Design of a beam optic for the transfer channel between the LINAC 2 and the 2.5 GeV synchrotron

International Nuclear Information System (INIS)

Schneider, W.

1992-10-01

The accelerator facility at the Physikalisches Institut of Bonn University is being extended by a linear accelerator (LINAC 2) for the preacceleration of polarized electron beams to an energy level of 20 MeV. The beam optics of the transfer channel, which guides the electrons to the injection point of the 2.5 GeV-Synchrotron, has been designed. Because the emittance of the electron beam leaving the LINAC 2 is unknown at the movement, the beam optics and the aperture of the transfer channel has been layed out for a high transmission even for the worst case scenario. The quadrupol magnets needed for focusing and matching the beam has been constructed and tested. The integration of a system for beam diagnosis and position correction in the transfer channel is planned. (orig.) [de

Improved performance of the control scheme for IUAC superconducting Linac

International Nuclear Information System (INIS)

Sahu, B.K.; Suman, S.K.; Kumar, R.

2015-01-01

Since many years energized ion beams from linac are being delivered routinely for scheduled experiments using all the three accelerating modules of linac along with super buncher and rebuncher. Major efforts are dedicated to improve the performance of the control scheme to minimise the down time of the linac during operation. Earlier, a number of developments were carried out to improve the dynamics of the control scheme. The most significant of them is the piezoelectric actuator based tuning mechanism which is implemented in all the operational resonators of second and third accelerating modules of superconducting linac. This has helped us to bridge the gap between the accelerating fields achieved during Q measurement at 6 W of helium power and during phase locking of the resonator during beam operation at a given RF power (∼120W). The piezoelectric actuator based tuner is also instrumental to reduce the unlocking rate of the resonators. Pulse width modulation (PWM) control based helium gas operated tuner is implemented in few resonators to improve phase locking performance. CAMAC based distributed control scheme is upgraded to VME based distributed control without changing the existing client interface to maintain uniformity between the Pelletron and linac control. Python code support has been implemented to protect the resonators against high forward power during unlocking. This is also integrated with the display status of the resonators for monitoring. A frequency to voltage converter is incorporated in control scheme to monitor the frequency error. This has helped us to develop a scheme for automatic phase locking of the cavities using piezoelectric actuator based tuner control. (author)

Proposed use of the radio-frequency quadrupole structure to funnel high-current ion beams

International Nuclear Information System (INIS)

Stokes, R.H.; Minerbo, G.N.

1985-01-01

In this paper, we describe a new approach to funneling beams that are initially accelerated in two radio-frequency quadrupole (RFQ) accelerators. Instead of discrete optical elements, we propose to funnel within an RFQ structure, so that during the funneling process the beam is always confined by periodic transverse focusing. Beams with high space charge experience irreversible emittance growth when they emerge from a periodic focusing system. To alleviate this problem, in the proposed funneling system it should be possible to maintain the same focusing periodicity as that of the accelerators preceding the funnel. Also, instead of conventional deflection systems, we propose to use the properties of a modified RFQ structure to deflect two parallel beams toward each other and to merge them into a single final beam. 1 ref., 3 figs

BEAM DYNAMICS STUDIES FOR A COMPACT CARBON ION LINAC FOR THERAPY

Energy Technology Data Exchange (ETDEWEB)

Plastun, A.; Mustapha, B.; Nassiri, A.; Ostroumov, P.

2016-05-01

Feasibility of an Advanced Compact Carbon Ion Linac (ACCIL) for hadron therapy is being studied at Argonne National Laboratory in collaboration with RadiaBeam Technologies. The 45-meter long linac is designed to deliver 109 carbon ions per second with variable energy from 45 MeV/u to 450 MeV/u. S-band structure provides the acceleration in this range. The carbon beam energy can be adjusted from pulse to pulse, making 3D tumor scanning straightforward and fast. Front end accelerating structures such as RFQ, DTL and coupled DTL are designed to operate at lower frequencies. The design of the linac was accompanied with extensive end-to-end beam dynamics studies which are presented in this paper.

Nuclear quadrupole interactions in ferroelectric compounds of HF/sup 181/

Energy Technology Data Exchange (ETDEWEB)

Kunzler, J V

1971-01-01

Measurements of nuclear quadrupole interaction constants in perovkite-type compounds of PbHfO/sub 3/, SnhfO/sub 3/, CaHfO/sub 3/ e SrHfO/sub 3/ have been performed using the perturbed angular correlation technique. A range of fundamental frequencies from 150 to 550 Megaradians per second was determined. The variation of quadrupole constants has been discussed through the molecular orbital theory.

High-beta linac structures

International Nuclear Information System (INIS)

Schriber, S.O.

1979-01-01

Accelerating structures for high-beta linacs that have been and are in use are reviewed in terms of their performance. Particular emphasis is given to room-temperature structures and the disk-and-washer structure. The disk-and-washer structure has many attractive features that are discussed for pulsed high-gradient linacs, for 100% duty-cycle medium-gradient linacs and for high-current linacs requiring maximal amounts of stored energy in the electric fields available to the beam

Development of an RFQ linac for unstable nuclei

International Nuclear Information System (INIS)

Arai, S.; Imanishi, A.; Morimoto, T.; Shibuya, S.; Tojyo, E.; Tokuda, N.

1990-05-01

A split coaxial RFQ (SCRFQ) is being developed for accelerating unstable nuclei with a charge-to-mass ratio larger than 1/60 from 1 to 170 keV/u in the JHP heavy-ion linac. The SCRFQ is equipped with modulated vanes to generate ideal quadrupole and accelerating fields. The fundamental problems on the SCRFQ have been clarified and solved through studies on a cold model, and the excellent accelerating performance has been confirmed by using a proton accelerating model working at 50 MHz. A 25.5-MHz prototype for the JHP SCRFQ is now under development. The prototype, 2.1 m in length and 0.9 m in diameter, will accelerate ions with a charge-to-mass ratio larger than 1/30 from 1 to 45 keV/u. Low-power tests conducted so far show that the prototype cavity has good rf characteristics. (author)

ISABELLE insertion quadrupoles

International Nuclear Information System (INIS)

Kaugerts, J.; Polk, I.; Sampson, W.; Dahl, P.F.

1979-01-01

Beam focussing and control at the beam intersection regions of ISABELLE is accomplished by a number of superconducting insertion quadrupoles. These magnets differ from the standard ISABELLE quadrupoles in various ways. In particular, the requirements of limited space near the intersections and aperture for beam extraction impose constraints on their configuration. To achieve optimum beam focussing and provide tuning flexibility calls for stronger quadrupole trim windings than those in the standard quadrupoles. The magnetic and mechanical design of the insertion quadrupoles and their associated correction and steering windings to accomplish the above tasks is presented

Passivation of boron in silicon by hydrogen and muonium: calculation of electric field gradients, quadrupole resonance frequencies and cross relaxation functions

International Nuclear Information System (INIS)

Maric, Dj.M.; Meier, P.F.; Vogel, S.; Davis, E.A.

1991-01-01

The possibility of studying impurity passivation complexes in semiconductors by quadrupole resonance spectroscopy is examined. The problem is illustrated for the case of boron in silicon passivated with hydrogen or, equivalently, with muonium, since the radioactive light isotope in principle offers a greater sensitivity for detection of the spectra. Ab initio calculations on suitable cluster models of the passivation complexes provide estimates of the electric field gradients at the quadrupolar nuclei, and thereby predictions of the quadrupole resonance frequencies. Detection via cross-relaxation techniques is proposed, notably muon level crossing resonance (μLCR), and illustrated by calculation of the time dependence of the muon polarization function. Possible reasons for the absence of quadrupolar resonances in μLCR spectra recorded in exploratory experiments are discussed; these include the existence of a local tunnelling mode for the lighter isotope. (author)

Linac 1, inner structure

CERN Multimedia

1968-01-01

This photo shows the inner structure of Linac 1. As injector to the PS, and later to the Booster, Linac 1 accelerated protons to 50 MeV, but it has also accelerated heavier ions. Fitted with a 520 keV RFQ pre-injector (instead of the original Cockcroft-Walton generator), it delivered protons and heavy ions to LEAR, from 1982 to 1992. After 33 years of faithful service, Linac 1 was dismantled in 1992 to make room for Linac 3 (Pb ions).

RFQ development at Los Alamos

International Nuclear Information System (INIS)

Wangler, T.P.; Crandall, K.R.; Stokes, R.H.

1982-01-01

The basic principles of the radio-frequency quadrupole (RFQ) linac are reviewed and a summary of past and present Los Alamos work is presented. Some beam-dynamics effects, important for RFQ design, are discussed. A design example is shown for xenon and a brief discussion of low-frequency RFQ structures is given

Signal multiplexing scheme for LINAC

International Nuclear Information System (INIS)

Sujo, C.I.; Mohan, Shyam; Joshi, Gopal; Singh, S.K.; Karande, Jitendra

2004-01-01

For the proper operation of the LINAC some signals, RF (radio frequency) as well as LF (low frequency) have to be available at the Master Control Station (MCS). These signals are needed to control, calibrate and characterize the RF fields in the resonators. This can be achieved by proper multiplexing of various signals locally and then routing the selected signals to the MCS. A multiplexing scheme has been designed and implemented, which will allow the signals from the selected cavity to the MCS. High isolation between channels and low insertion loss for a given signal are important issues while selecting the multiplexing scheme. (author)

Drift tubes of Linac 2

CERN Multimedia

CERN PhotoLab

1977-01-01

With the advent of the 800 MeV PS Booster in 1972, the original injector of the PS, a 50 MeV Alvarez-type proton linac, had reached its limits, in terms of intensity and stability. In 1973 one therefore decided to build a new linac (Linac 2), also with a drift-tube Alvarez structure and an energy of 50 MeV. It had a new Cockcroft-Walton preinjector with 750 keV, instead of the previous one with 500 keV. Linac 2 was put into service in 1980. The old Linac 1 was then used for the study of, and later operation with, various types of ions. This picture shows Linac 2 drift-tubes, suspended on stems coming from the top, in contrast to Linac 1, where the drift-tubes stood on stems coming from the bottom.

Evaluation of the CERN Super Proton Synchrotron longitudinal impedance from measurements of the quadrupole frequency shift

Directory of Open Access Journals (Sweden)

A. Lasheen

2017-06-01

Full Text Available Longitudinal instabilities are one of the main limitations in the CERN Super Proton Synchrotron (SPS to reach the beam parameters required for the High Luminosity LHC project. In preparation to the SPS upgrade, possible remedies are studied by performing macroparticle simulations using the machine impedance model obtained from electromagnetic simulations and measurements. To benchmark the impedance model, the results of simulations are compared with various beam measurements. In this study, the reactive part of the impedance was probed by measuring the quadrupole frequency shift with intensity, obtained from bunch length oscillations at mismatched injection into the SPS. This method was applied over many last years to follow up the evolution of the SPS impedance, injecting bunches with the same bunch length. A novel approach, giving significantly more information, consists in varying the injected bunch length. The comparison of these measurements with macroparticle simulations allowed us to test the existing model, identify some missing SPS impedance and to obtain its possible dependence on frequency.

High speed resonant frequency determination applied to field mapping using perturbation techniques

International Nuclear Information System (INIS)

Smith, B.H.; Burton, R.J.; Hutcheon, R.M.

1992-01-01

Perturbation techniques are commonly used for measuring electric and magnetic field distributions in resonant structures. A field measurement system has been assembled using a Hewlett Packard model 8753C network analyzer interfaced via an HPIB bus to a personal computer to form an accurate, rapid and flexible system for data acquisition, control, and analysis of such measurements. Characterization of long linac structures (up to 3 m) is accomplished in about three minutes, minimizing thermal drift effects. This paper describes the system, its application and its extension to applications such as confirming the presence of weak, off-axis quadrupole fields in an on-axis coupled linac. (Author) 5 figs., 10 refs

Compendium of Scientific Linacs

Energy Technology Data Exchange (ETDEWEB)

Clendenin, James E

2003-05-16

The International Committee supported the proposal of the Chairman of the XVIII International Linac Conference to issue a new Compendium of linear accelerators. The last one was published in 1976. The Local Organizing Committee of Linac96 decided to set up a sub-committee for this purpose. Contrary to the catalogues of the High Energy Accelerators which compile accelerators with energies above 1 GeV, we have not defined a specific limit in energy. Microtrons and cyclotrons are not in this compendium. Also data from thousands of medical and industrial linacs has not been collected. Therefore, only scientific linacs are listed in the present compendium. Each linac found in this research and involved in a physics context was considered. It could be used, for example, either as an injector for high energy accelerators, or in nuclear physics, materials physics, free electron lasers or synchrotron light machines. Linear accelerators are developed in three continents only: America, Asia, and Europe. This geographical distribution is kept as a basis. The compendium contains the parameters and status of scientific linacs. Most of these linacs are operational. However, many facilities under construction or design studies are also included. A special mention has been made at the end for the studies of future linear colliders.

Design and results of the radio frequency quadrupole RF system at the Superconducting Super Collider Laboratory

International Nuclear Information System (INIS)

Grippe, J.; Marsden, E.; Marrufo, O.; Regan, A.; Rees, D.; Ziomek, C.

1993-05-01

The Superconducting Super Collider Laboratory (SSCL) and the Los Alamos National Laboratory (LANL) entered into a joint venture to design and develop a 600 kW amplifier and its low-level controls for use in the Radio-Frequency Quadrupole (RFQ) accelerating cavity of the SSC. The design and development work has been completed. After being tested separately, the high power amplifier and low level RF control system were integrated and tested on a test cavity. Results of that tests are given. Tests were then carried out on the actual RFQ with and without the presence of the accelerated beam. Results of these tests are also given, along with the phase and amplitude information

Design and application possibilities of superconducting radio-frequency quadrupoles

International Nuclear Information System (INIS)

Schempp, A.; Deitinghoff, H.

1990-01-01

In recent experiments, cw surface electric fields in excess of 100 MV/m have been obtained in a superconducting rf quadrupole (SCRFQ) device. In this paper we explore some design and application possibilities of SCRFQs which have been opened by these results. For example, SCRFQs may be able to accelerate higher cw currents than is now possible. Also, highly-modulated SCRFQs could be designed to provide compact, high-longitudinal-gradient devices. Some conceptual designs and applications will be discussed. 15 refs., 2 figs

Effects of correlations between particle longitudinal positions and transverse plane on bunch length measurement: a case study on GBS electron LINAC at ELI-NP

Science.gov (United States)

Sabato, L.; Arpaia, P.; Cianchi, A.; Liccardo, A.; Mostacci, A.; Palumbo, L.; Variola, A.

2018-02-01

In high-brightness LINear ACcelerators (LINACs), electron bunch length can be measured indirectly by a radio frequency deflector (RFD). In this paper, the accuracy loss arising from non-negligible correlations between particle longitudinal positions and the transverse plane (in particular the vertical one) at RFD entrance is analytically assessed. Theoretical predictions are compared with simulation results, obtained by means of ELEctron Generation ANd Tracking (ELEGANT) code, in the case study of the gamma beam system (GBS) at the extreme light infrastructure—nuclear physics (ELI-NP). In particular, the relative error affecting the bunch length measurement, for bunches characterized by both energy chirp and fixed correlation coefficients between longitudinal particle positions and the vertical plane, is reported. Moreover, the relative error versus the correlation coefficients is shown for fixed RFD phase 0 rad and π rad. The relationship between relative error and correlations factors can help the decision of using the bunch length measurement technique with one or two vertical spot size measurements in order to cancel the correlations contribution. In the case of the GBS electron LINAC, the misalignment of one of the quadrupoles before the RFD between  -2 mm and 2 mm leads to a relative error less than 5%. The misalignment of the first C-band accelerating section between  -2 mm and 2 mm could lead to a relative error up to 10%.

Superconducting heavy-ion linacs

International Nuclear Information System (INIS)

Bollinger, L.M.

1977-01-01

A summary is given of plans developed by four different groups for the construction of small superconducting linacs to boost the energy of heavy ions from existing tandem electrostatic accelerators. The projects considered are the linac under construction at Argonne and the design efforts at Karlsruhe, at Stanford, and by a Cal Tech-Stony Brook collaboration. The intended uses of the accelerator systems are stated. Beam dynamics of linacs formed of short independently-phased resonators are reviewed, and the implications for performance are discussed. The main parameters of the four linacs are compared, and a brief analysis of accelerating structures is given

Research on backward traveling wave electron linac

International Nuclear Information System (INIS)

Chen Huaibi; Zheng Shuxin; Ding Xiaodong; Lin Yuzheng

1999-01-01

Future electron linacs require high gradient acceleration. The studies on the high shunt impedance backward traveling wave electron linac accelerating structure (BTW) are presented. At first, the characteristics of BTW are researched. The option of mode and optimal design methods of accelerating cavity for BTW are studied. A physical design method for BTW accelerators, including longitudinal and transversal particle dynamics, is given. Based on above studies, a 9 MeV BTW accelerating tube at 3π/4 mode with frequency 2856 MHz for inspecting large container as radiation source at customs is designed, and a comparison with disk-loaded waveguide accelerating tube is made. The result of research leads to the conclusion that backward traveling wave accelerating structure is preferable. Because BTW has higher effective shunt impedance, shorter filling time and more stable operation

Design and development of R.F. LINAC accelerator components

International Nuclear Information System (INIS)

Abhay Kumar; Guha, S.; Balasubramaniam, R.; Jawale, S.B.

2003-01-01

Full text: Radio frequency linear accelerator, a high power electron LINAC technology, is being developed at BARC. These accelerators are considered to be the most compact and effective for a given power capacity. Important application areas of this LINAC include medical sterilization, food preservation, pollution control, semiconductor industries, radiation therapy and material science. Center for Design and Manufacture (CDM), BARC has been entrusted with the design, development and manufacturing of various mechanical components of the accelerator. Most critical and precision components out of them are Diagnostic chamber, Faraday cup, Drift tube and R.F. cavities. This paper deals with the design aspects in respect of Ultra high vacuum compatibility and the mechanism of operation. Also this paper discusses the state-of-art technology for machining of intricate contour using specially designed poly crystalline diamond tool and the inspection methodology developed to minimize the measurement errors on the machined contour. Silver brazing technique employed to join the LINAC cavities is also described in detail

Beam dynamics simulations for linacs driving short-wavelength FELs

International Nuclear Information System (INIS)

Ferrario, M.; Tazzioli, F.

1999-01-01

The fast code HOMDYN has been recently developed, in the framework of the TTF (Tesla test facility) collaboration, in order to study the beam dynamics of linacs delivering high brightness beams as those needed for short wavelength Fel experiments. These linacs are typically driven by radio-frequency photo-injectors, where correlated time dependent space charge effects are of great relevance: these effects cannot be studied by standard beam optics codes (TRACE3D, etc.) and they have been modeled so far by means of multi-particle (Pic or quasistatic) codes requiring heavy cpu time and memory allocations. HOMDYN is able to describe the beam generation at the photo-cathode and the emittance compensation process in the injector even running on a laptop with very modest running rimes (less than a minute). In this paper it is showed how this capability of the code is exploited so to model a whole linac up to the point where the space charge dominated regime is of relevance (200 MeV)

Superconducting linac booster

International Nuclear Information System (INIS)

Srinivasan, B.; Betigeri, M.G.; Pandey, M.K.; Pillay, R.G.; Kurup, M.B.

1997-01-01

The report on superconducting LINAC booster, which is a joint project of Bhabha Atomic Research Centre (BARC) and Tata Institute of Fundamental Research (TIFR), brings out the work accomplished so far towards the development of the technology of superconducting LINAC to boost the energy of ions from the 14UD Pelletron. The LINAC is modular in construction with each module comprising of a helium cryostat housing four lead-plated quarter wave resonators. The resonators are superconducting for temperatures below 7.19K. An energy boost of 2 MeV/q per module is expected to be achieved. The first module and the post-tandem superbuncher have been fabricated and tested on the LINAC beam line. This report gives a summary of the technological achievements and also brings out the difficulties encountered during the R and D phase. (author)

Upgrade of the radio frequency quadrupole cooler and buncher for the HIE-ISOLDE project

CERN Document Server

Babcock, Carla

2013-01-01

The upgrade to the ISOLDE facility, HIE-ISOLDE, will include an upgrade to the RFQCB (radio frequency quadrupole cooler and buncher), the focus of which will be fixing the problems of alignment with the current machine, improving the integrity of the vacuum system, stabilizing the internal gas pressure, and the changes associated with a new position. The beam passage inside the RFQCB has been simulated with an independent code to highlight the importance of the internal gas pressure, to motivate design changes in the new RFQCB and to explain ways to improve the performance of the current machine. The suspected misalignment of ISCOOL has been quantified, and, using a simulation of ions passing through the external injection electrodes, the effect of the misalignment on machine acceptance has been detailed. Plans for the future RFQCB test stand and HIE-ISOLDE installation have been outlined. (C) 2013 Elsevier B.V. All rights reserved.

Analysis of the LSC microbunching instability in MaRIE linac reference design

International Nuclear Information System (INIS)

Yampolsky, Nikolai

2016-01-01

In this report we estimate the effect of the microbunching instability in the MaRIE XFEL linac. The reference design for the linac is described in a separate report. The parameters of the L1, L2, and L3 linacs as well as BC1 and BC2 bunch compressors were the same as in the referenced report. The beam dynamics was assumed to be linear along the accelerator (which is a reasonable assumption for estimating the effect of the microbunching instability). The parameters of the bunch also match the parameters described in the referenced report. Additionally, it was assumed that the beam radius is equal to R = 100 m and does not change along linac. This assumption needs to be revisited at later studies. The beam dynamics during acceleration was accounted in the matrix formalism using a Matlab code. The input parameters for the linacs are: RF peak gradient, RF frequency, RF phase, linac length, and initial beam energy. The energy gain and the imposed chirp are calculated based on the RF parameters self-consistently. The bunch compressors are accounted in the matrix formalism as well. Each chicane is characterized by the beam energy and the R56 matrix element. It was confirmed that the linac and beam parameters described previously provide two-stage bunch compression with compression ratios of 10 and 20 resulting in the bunch of 3kA peak current.

Ab initio determination of the nuclear quadrupole moments of 114In, 115In, and 117In

International Nuclear Information System (INIS)

Errico, Leonardo A.; Renteria, Mario

2006-01-01

We present here ab initio determinations of the nuclear-quadrupole moment Q of hyperfine-probe-nuclear states of three different In isotopes: the 5 + 192 keV excited state of 114 In (probe for nuclear quadrupole alignment spectroscopy), the 9/2 + ground state of 115 In (nuclear magnetic and nuclear quadrupole resonance probe), and the 3/2 + 659 keV excited state of 117 In (perturbed angular correlations probe). These nuclear-quadrupole moments were determined by comparing experimental nuclear-quadrupole frequencies to the electric field gradient tensor calculated with high accuracy at In sites in metallic indium within the density functional theory. These ab initio calculations were performed with the full-potential linearized augmented plane wave method. The results obtained for the quadrupole moments of 114 In [Q( 114 In)=-0.14(1) b] are in clear discrepancy with those reported in the literature [Q( 114 In)=+0.16(6) b and +0.739(12) b]. For 115 In and 117 In our results are in excellent agreement with the literature and in the last case Q( 117 In) is determined with more precision. In the case of Q( 117 In), its sign cannot be determined because standard γ-γ perturbed angular correlations experiments are not sensitive to the sign of the nuclear-quadrupole frequency

Construction of SPring-8 LINAC

International Nuclear Information System (INIS)

Yokomizo, Hideaki; Yoshikawa, Hiroshi; Suzuki, Shinsuke; Yanagida, Ken-ichi; Mizuno, Akihiko; Hori, Toshihiko; Tamezane, Kenji; Kodera, Masahiko; Sakaki, Hironao; Mashiko, Katsuo

1993-01-01

Construction of the linac building has been started in February 1993. The components of the linac are under manufacturing. The preinjector of linac was already constructed and temporarily installed in Tokai Establishment in order to test the beam quality. (author)

Linac pre-injector

CERN Multimedia

CERN PhotoLab

1965-01-01

New accelerating column of the linac pre-injector, supporting frame and pumping system. This new system uses two mercury diffusion pumps (in the centre) and forms part of the modifications intended to increase the intensity of the linac. View taken during assembly in the workshop.

Linacs for medical isotope production

International Nuclear Information System (INIS)

Pramudita, A.

2012-01-01

This paper reviews efforts on using high energy (25-30 MeV) and high power (10-20 kW) electron linacs and lower energy (7 MeV) proton linacs for medical radioisotope production. Using high energy x-rays from the electron linacs, PET (Positron Emission Tomography) radioisotopes are produced through photonuclear reactions such as 19 F(γ,n) 18 F, which also allow production of other PET radionuclides 11 C, 13 N, and 15 O. Other mostly used medical radionuclides 99m Tc can also be obtained by using the electron linacs, through photofission or photonuclear reactions. Proton linacs for PET have also been recently developed and the product has been available in the market since 2005. The linacs have been tested for 18 F production. As a proton accelerator, the target systems and nuclear reactions are similar to the ones used in PET cyclotrons. (author)

Linac4 Technical Design Report

CERN Document Server

Arnaudon, L; Baylac, M; Bellodi, G; Body, Y; Borburgh, J; Bourquin, P; Broere, J; Brunner, O; Bruno, L; Carli, C; Caspers, Friedhelm; Cousineau, S M; Cuvet, Y; De Almeida Martins, C; Dobers, T; Fowler, T; Garoby, R; Gerigk, F; Goddard, B; Hanke, K; Hori, M; Jones, M; Kahle, K; Kalbreier, Willi; Kroyer, T; Küchler, D; Lombardi, A M; López-Hernandez, L A; Magistris, M; Martini, M; Maury, S; Page, E; Paoluzzi, M; Pasini, M; Raich, U; Rossi, C; Royer, J P; Sargsyan, E; Serrano, J; Scrivens, R; Silari, M; Timmins, M; Venturini-Delsolaro, W; Vretenar, M; Wegner, R; Weterings, W; Zickler, T

2006-01-01

Linac4 is an H- linear accelerator, intended to replace Linac2 as injector to the PS Booster (PSB). By delivering to the PSB a beam at 160 MeV energy, Linac4 will provide the conditions to double the brightness and intensity of the beam from the PSB, thus removing the first bottleneck towards higher brightness for the LHC and simplifying operation. Moreover, this new linac constitutes an essential component of any of the envisaged LHC upgrade scenarios and could open the way to future extensions of the CERN accelerator complex towards higher performance. This Technical Design Report presents a detailed technical overview of the Linac4 design as it stands at end 2006.

The source development lab linac at BNL

International Nuclear Information System (INIS)

Graves, W.S.; Johnson, E.D.

1996-12-01

A 210 MeV SLAC-type electron linac is currently under construction at BNL as part of the Source Development Laboratory. A 1.6 cell RF photoinjector is employed as the high brightness electron source which is excited by a frequency tripled Titanium:Sapphire laser. This linac will be used for several source development projects including a short bunch storage ring, and a series of FEL experiments based on the 10 m long NISUS undulator. The FEL will be operated as either a SASE or seeded beam device using the Ti:Sapp laser. For the seeded beam experiments; direct amplification, harmonic generation, and chirped pulse amplification modes will be studied, spanning an output wavelength range from 900 nm down to 100 nm. This paper presents the project's design parameters and results of recent modeling using the PARMELA and MAD simulation codes

TOP LINAC design; Progetto del TOP LINAC

Energy Technology Data Exchange (ETDEWEB)

Picardi, L; Ronsivalle, C; Vignati, A [ENEA, Centro Ricerche Frascati, Rome (Italy). Dip. Innovazione

1997-11-01

The report describes a linear accelerator for protons named TOP LINAC designed for the TOP (Terapia Oncologica con Protoni, Oncological Protontherapy) project launched by the Italian National Institute of Health (Istituto Superiore di Sanita`, ISS) to explore in collaboration with the biggest Oncological Hospital in Rome (Istituto Regina Elena, IRE) the potentialities of the therapy with accelerated protons and establish guide lines for the application of this new type of radiotherapy in comparison with the more traditional electron and x-rays radiotherapy. The concept of a compact accelerator for protontherapy applications bore within the Italian Hadrontherapy Collaboration (TERA Collaboration) with the aim to diffuse the protontherapy on the National territory. The ISS program plans to use the TOP linac proton beam also for production of PET (Positron Emission Tomography) radioisotopes and radiobiology studies. Official agreements are in course between ISS and ENEA which provides its experience in the industrial and medical accelerators for the design and the construction of the TOP linac. The accelerator that will be the first 3 GHz proton linac in the world, will be composed of a 428.3 MHz 7 Me V RFQ + DTL injector followed by a 7-65 Me V section of a 3 GHz SCDTL structure and a 65 - 200 Me V variable energy SCL 3 GHz structure. In particular the SCDTL section uses a highly innovative accelerating structure patented by ENEA. In this report the clinical and physical requests are discussed and a preliminary design of the whole machine is given.

Simultaneous optimization of the cavity heat load and trip rates in linacs using a genetic algorithm

Directory of Open Access Journals (Sweden)

Balša Terzić

2014-10-01

Full Text Available In this paper, a genetic algorithm-based optimization is used to simultaneously minimize two competing objectives guiding the operation of the Jefferson Lab’s Continuous Electron Beam Accelerator Facility linacs: cavity heat load and radio frequency cavity trip rates. The results represent a significant improvement to the standard linac energy management tool and thereby could lead to a more efficient Continuous Electron Beam Accelerator Facility configuration. This study also serves as a proof of principle of how a genetic algorithm can be used for optimizing other linac-based machines.

Inner structure of Linac 2

CERN Multimedia

CERN PhotoLab

1977-01-01

With the advent of the 800 MeV Booster in 1972, the original injector of the PS, a 50 MeV Alvarez-type proton linac, had reached its limits, in terms of intensity and stability. In 1973 one therefore decided to build a new linac (Linac 2), also with a drift-tube Alvarez structure and an energy of 50 MeV. It had a new Cockcroft-Walton preinjector with 750 keV, instead of the previous one with 500 keV. Linac 2 was put into service in 1980. The old Linac 1 was then used for the study of, and later operation with, various types of ions. This picture shows the inner structure of Linac 2, with drift-tubes hanging on stems under a rigid support structure, soon to be mounted inside tank 1 (750 keV to 10 MeV, the lowest-energy one of 3). Frank Malthouse is standing in the background.

Temperature control feedback loops for the linac upgrade side coupled cavities at Fermilab

International Nuclear Information System (INIS)

Crisp, J.

1990-01-01

The linac upgrade project at Fermilab will replace the last 4 drift-tube linac tanks with seven side coupled cavity strings. This will increase the beam energy from 200 to 400 MeV at injection into the Booster accelerator. The main objective of the temperature loop is to control the resonant frequency of the cavity strings. A cavity string will constant of 4 sections connected with bridge couplers driven with a 12 MW klystron at 805 MHz. Each section is a side coupled cavity chain consisting of 16 accelerating cells and 15 side coupling cells. For the linac upgrade, 7 full cavity strings will be used. A separate temperature control system is planned for each of the 28 accelerating sections, the two transition sections, and the debuncher section. The cavity strings will be tuned to resonance for full power beam loaded conditions. A separate frequency loop is planned that will sample the phase difference between a monitor placed in the end cell of each section and the rf drive. The frequency loop will control the set point for the temperature loop which will be able to maintain the resonant frequency through periods within beam or rf power. The frequency loop will need the intelligence required to determine under what conditions the phase error information is valid and the temperature set point should be adjusted. This paper will discuss some of the reason for temperature control, the implementation, and some of the problems encountered. An appendix contains some useful constants and descriptions of some of the sensor and control elements used. 13 figs

The design of a radio frequency quadrupole LINAC for the RIB ...

Indian Academy of Sciences (India)

α-particle beams from the variable energy cyclotron at VECC will be .... The calculated power loss density distribution in the RFQ post – the highest power ... rf-Structure measurements have been done using a Network Analyser (model 8753E).

Design and construction of a large aperture, quadrupole electromagnet prototype for ILSE

International Nuclear Information System (INIS)

Stuart, M.; Faltens, A.; Fawley, W.M.; Peters, C.; Vella, M.C.

1995-04-01

We are currently constructing a prototype quadrupole electromagnet for the proposed Induction Linac Systems Experiment (ILSE) at LBL. ILSE will address many physi and engineering issues relevant to the design of a heavy-ion fusion driver accelerator. The pulsed electromagnet has two layers of current windings and will produce a field gradient exceeding 25 T/m at a repetition rate of 1 Hz steady-state. In this paper, we discuss how the interaction of various concerns such as maximum dynamic aperture, short lattice period, field quality, iron yoke weight, heat transfer, and voltage standoff have led to our particular design choices. We also present 2- and 3-D numerical calculations concerning field topography and the results of transport simulations of space-charge dominated ion beams with ILSE parameters

Light ion linacs for medical applications

International Nuclear Information System (INIS)

Bradbury, J.N.; Knapp, E.A.; Nagle, D.E.

1975-01-01

Recent advances in linear accelerator technology point to the feasibility of designing and developing practical medical linacs for producing protons, neutrons, or π mesons for the radiation therapy of cancer. Additional uses of such linacs could include radioisotope production and charged particle radiography. For widespread utilization medical linacs must exhibit reasonable cost, compactness, reliability, and simplicity of operation. Possible extensions of current accelerator technology which might provide these characteristics are discussed in connection with linac design, fabrication techniques, materials, power sources, injectors, and particle collection and delivery systems. Parameters for a medical proton linac for producing pions are listed. (U.S.)

Nuclear quadrupole resonance of arsenolite

International Nuclear Information System (INIS)

Madarazo, R.

1988-01-01

A pulsed Nuclear Quadrupole Resonance (NQR) spectrometer was constructed using imported Matec units. Peripherical components were specially assembled and tested for the implantation of the spin-echo technique in the Laboratorio de Centros de Cor of IFUSP. The R.F. operation range is from 50 to 1 ) and spin-spin (T 2 ) relaxation times were carried out at room temperature in arsenolite. The 75 As NQR frequency measured at room temperature is 116.223 MHz. (author) [pt

Eight piece quadrupole magnet, method for aligning quadrupole magent pole tips

Science.gov (United States)

Jaski, Mark S.; Liu, Jie; Donnelly, Aric T.; Downey, Joshua S.; Nudell, Jeremy J.; Jain, Animesh

2018-01-30

The invention provides an alternative to the standard 2-piece or 4-piece quadrupole. For example, an 8-piece and a 10-piece quadrupole are provided whereby the tips of each pole may be adjustable. Also provided is a method for producing a quadrupole using standard machining techniques but which results in a final tolerance accuracy of the resulting construct which is better than that obtained using standard machining techniques.

25th anniversary for Linac-2

CERN Multimedia

2003-01-01

On Friday, 3 October 2003, the Linac team celebrated a quarter century of successful operation of one of its linear accelerators: Linac-2, the proton workhorse of the CERN accelerator complex. Linac-2, CERN's linear proton accelerator, has now been running for 25 years - ample reason for a small celebration. About 30 members of the original team (10 of the initially more than 50 are still working at CERN), and other CERN personnel met on 3 October 2003. Linac-2 is the first link in the accelerator chain Linac-2 - PS Booster - PS - SPS and eventually LHC. Beams from Linac-2 are used after further acceleration in the CERN complex for SPS fixed target physics; for antiproton production for the Antiproton Decelerator (AD); for test beams in the East Experimental Hall and in the PS; for nuclear physics at ISOLDE; for LHC test beams and in the past for both ISR physics and Antiproton production (AA/AC) and test beams in LEAR. Linac-2 was built to obtain higher intensities and better stability than with ...

Workshop: Linac90

Energy Technology Data Exchange (ETDEWEB)

Van Dyck, Olin

1990-12-15

In 1960 the first linear accelerator (linac) conference was organized at Brookhaven by John Blewett. In the few years following, linear accelerator energies jumped from 50 MeV (at Brookhaven and CERN) to 2 GeV at Stanford. With the realization that, at least for electrons, circular accelerators have reached their practical limits, linacs are once more in the spotlight.

Workshop: Linac90

International Nuclear Information System (INIS)

Van Dyck, Olin

1990-01-01

In 1960 the first linear accelerator (linac) conference was organized at Brookhaven by John Blewett. In the few years following, linear accelerator energies jumped from 50 MeV (at Brookhaven and CERN) to 2 GeV at Stanford. With the realization that, at least for electrons, circular accelerators have reached their practical limits, linacs are once more in the spotlight

Injector linac of SPring-8

International Nuclear Information System (INIS)

Yoshikawa, H.; Hori, T.; Suzuki, S.; Yanagida, K.; Itoh, Y.; Mizuno, A.; Taniuchi, T.; Sakaki, H.; Kuba, A.; Fukushima, S.; Kobayashi, T.; Asaka, T.; Yokomizo, H.

1996-01-01

The linac that is SPring-8 injector was completed and started operation from August 1. A beam was able to be transported to the final beam dumping at a tail end on August 8. From now on this linac carries out beam adjustment and be scheduled to do a beam injection to a synchrotron in October. The construction and fundamental performance of the linac are described. (author)

Intense ion beam transport in magnetic quadrupoles: Experiments on electron and gas effects

International Nuclear Information System (INIS)

Seidl, P.A.; Molvik, A.W.; Bieniosek, F.M.; Cohen, R.H.; Faltens, A.; Friedman, A.; Kireef Covo, M.; Lund, S.M.; Prost, L.; Vay, J-L.

2004-01-01

Heavy-ion induction linacs for inertial fusion energy and high-energy density physics have an economic incentive to minimize the clearance between the beam edge and the aperture wall. This increases the risk from electron clouds and gas desorbed from walls. We have measured electron and gas emission from 1 MeV K + incident on surfaces near grazing incidence on the High-Current Experiment (HCX) at LBNL. Electron emission coefficients reach values >100, whereas gas desorption coefficients are near 10 4 . Mitigation techniques are being studied: A bead-blasted rough surface reduces electron emission by a factor of 10 and gas desorption by a factor of 2. We also discuss the results of beam transport (of 0.03-0.18 A K + ) through four pulsed room-temperature magnetic quadrupoles in the HCX at LBNL. Diagnostics are installed on HCX, between and within quadrupole magnets, to measure the beam halo loss, net charge and expelled ions, from which we infer gas density, electron trapping, and the effects of mitigation techniques. A coordinated theory and computational effort has made significant progress towards a self-consistent model of positive-ion beam and electron dynamics. We are beginning to compare experimental and theoretical results

Electron Linacs for High Energy Physics

International Nuclear Information System (INIS)

Wilson, Perry B.

2011-01-01

The purpose of this article is to introduce some of the basic physical principles underlying the operation of electron linear accelerators (electron linacs). Electron linacs have applications ranging from linacs with an energy of a few MeV, such that the electrons are approximately relativistic, to future electron-positron linear colliders having a collision energy in the several-TeV energy range. For the most part, only the main accelerating linac is treated in this article.

Resonator controller for the super-conducting LINAC

International Nuclear Information System (INIS)

Joshi, Gopal; Sujo, C.I.; Karande, Jitendra

2001-01-01

A resonator controller has been developed at Electronics Division, BARC, to stabilize the amplitude and phase of RF fields in the super-conducting resonators of BARC-TIFR linac. Due to reduced losses these resonators have intrinsic bandwidth of the order of one hertz at 150MHz whereas the vibration induced center frequency changes are of the order of a few hertz. In the control strategy followed the resonator is made the frequency selective part of an oscillator. The phase lock is achieved by dynamically adding a phase shift in the oscillator. In this paper we present the control strategy, implementation details and performance obtained with this controller. (author)

The KAERI 10 MeV Electron Linac - Description and Operational Manual

Energy Technology Data Exchange (ETDEWEB)

Lee, Byung Cheol; Park, Seong Hee; Jung, Young Uk; Han, Young Hwan; Kang, Hee Young

2005-06-15

The objective of this technical report is to guide the right operation and maintenance of the KAERI electron linac system. The KAERI electron linac system consists of 2 MeV injector based on 176 MHz Normal conducting RF (Radio Frequency)cavity and 10 MeV main accelerator based on 352 MHz Superconducting RF cavity, electron beamlines (injection and extraction). Since a electron accelerator generates hazard radiation, this system is located at the shielded room in basement and we can operate the system using the remote control system. It includes the description and the operational manual as well as the detailed technical direction for trouble shooting.

The KAERI 10 MeV Electron Linac - Description and Operational Manual

International Nuclear Information System (INIS)

Lee, Byung Cheol; Park, Seong Hee; Jung, Young Uk; Han, Young Hwan; Kang, Hee Young

2005-06-01

The objective of this technical report is to guide the right operation and maintenance of the KAERI electron linac system. The KAERI electron linac system consists of 2 MeV injector based on 176 MHz Normal conducting RF (Radio Frequency)cavity and 10 MeV main accelerator based on 352 MHz Superconducting RF cavity, electron beamlines (injection and extraction). Since a electron accelerator generates hazard radiation, this system is located at the shielded room in basement and we can operate the system using the remote control system. It includes the description and the operational manual as well as the detailed technical direction for trouble shooting

Improvement of the Longitudinal Beam Dynamics Tuning Procedure for the MSU RIA Driver Linac

CERN Document Server

Doleans, Marc; Grimm, Terry L; Marti, Felix; Wu, Xiaoyu; York, Richard

2005-01-01

The Rare Isotope Accelerator (RIA) driver linac will use a superconducting, cw linac with independently phased superconducting radio frequency cavities for acceleration and, for the heavier ions, utilize beams of multiple-charge-states (multi-q). Given the acceleration of multi-q beams and a stringent beam loss requirement in the RIA driver linac, a new beam envelope code capable of simulating nonlinearities of the multi-q beam envelopes in the longitudinal phase space was developed. Using optimization routines, the code is able to maximize the linearity of the longitudinal phase space motion and thereby minimizing beam loss by finding values for the amplitude and phase of the cavities for a given accelerating lattice. Relative motion of the multi-q beams is also taken into account so that superposition of the beam centroids and matching of their Twiss parameters are automatically controlled. As a result, the linac tuning procedure has been simplified and the longitudinal lattice performance has been improved...

Dipole, quadrupole, and octupole terms in the long-range hyperfine frequency shift for hydrogen in the presence of inert gases

International Nuclear Information System (INIS)

Greenwood, W.G.; Tang, K.T.

1987-01-01

The R -6 , R -8 , and R -10 terms in the long-range expansion for the hyperfine frequency shift are calculated for hydrogen in the presence of He, Ne, Ar, Kr, and Xe. The R -6 terms are based on the dipole oscillator strength sums. For helium, the R -8 and R -10 terms are based on quadrupole and octupole oscillator strength sums. For the heavier inert gases, the results for the R -8 and R -10 terms are obtained from the sum rules and the static polarizabilities. Upper bounds are also determined for the R -8 and R -10 terms

Review of superconducting linacs

International Nuclear Information System (INIS)

Bollinger, L.M.

1992-01-01

This paper summarizes the status of the technology of superconducting (SC) linacs designed for the acceleration of ions. The emphasis is on the technical issues involved, with only brief descriptions of the numerous linacs now in operation or under construction. Recent developments of special interest are treated in more detail, and remaining technical challenges are outlined. The technology required for acceleration of ions with velocity β ∼ 1 is not discussed because it is almost the same as for relativistic electrons. That is, this paper is mainly about SC linacs for low-velocity heavy ions. (Author) 5 tabs., 6 figs., 29 refs

Review of induction LINACS

International Nuclear Information System (INIS)

Faltens, A.; Keefe, D.

1981-10-01

There has been a recent upsurge of activity in the field of induction linacs, with several new machines becoming operational and others in the design stages. The performance levels of electron machines have reached 10's of kiloamps of current and will soon reach 10's of MeV's of energy. Acceleration of ion current has been demonstrated, and the study of a 10 GeV heavy ion induction linac for ICF continues. The operating principles of induction linacs are reviewed with the emphasis on design choices which are important for increasing the maximum beam currents

Review of induction linacs

International Nuclear Information System (INIS)

Faltens, A.; Keefe, D.

1982-01-01

There has been a recent upsurge of activity in the field of induction linacs, with several new machines becoming operational and others in the design stages. The performance levels of electron machines have reached 10's of kiloamps of current and will soon reach 10's of MeV's of energy. Acceleration of several kiloamps of ion current has been demonstrated, and the study of a 10 GeV heavy ion induction linac for ICF continues. The operating principles of induction linacs are reviewed with the emphasis on design choices which are important for increasing the maximum beam currents

Noise Reduction and Correction in the IPNS Linac ESEM

Science.gov (United States)

Dooling, J. C.; Brumwell, F. R.; Donley, L.; McMichael, G. E.; Stipp, V. F.

2004-11-01

The Energy Spread and Energy Monitor (ESEM) is an on-line, non-intrusive diagnostic used to characterize the output beam from the 200-MHz, 50-MeV IPNS linac. The energy spread is determined from a 3-size, longitudinal emittance measurement; whereas the energy is derived from time of flight (TOF) analysis. Signals are detected on 50-ohm, stripline beam position monitors (BPMs) terminated in their characteristic impedance. Each BPM is constructed with four striplines: top, bottom, left and right. The ESEM signals are taken from the bottom stripline in four separate BPM locations in the 50-MeV transport line between the linac and the synchrotron. Deterministic linac noise is sampled before and after the 70-microsecond macropulse. The noise phasor is vectorially subtracted from the beam signal. Noise subtraction is required at several frequencies, especially the fundamental and fifth harmonics (200 MHz and 1 GHz). It is also necessary to correct for attenuation and dispersion in the co-axial signal cables. Presently, the analysis assumes a single particle distribution to determine energy and energy spread. Work is on-going to allow for more realistic longitudinal distributions to be included in the analysis.

RESONANCE CONTROL FOR THE COUPLED CAVITY LINAC AND DRIFT TUBE LINAC STRUCTURES OF THE SPALLATION NEUTRON SOURCE LINAC USING A CLOSED-LOOP WATER COOLING SYSTEM

International Nuclear Information System (INIS)

Bernardin, J.D.; Brown, R.L.

2001-01-01

The Spallation Neutron Source (SNS) is a facility being designed for scientific and industrial research and development. SNS will generate and use neutrons as a diagnostic tool for medical purposes, material science, etc. The neutrons will be produced by bombarding a heavy metal target with a high-energy beam of protons, generated and accelerated with a linear particle accelerator, or linac. The low energy end of the linac consists of two room temperature copper structures, the drift tube linac (DTL), and the coupled cavity linac (CCL). Both of these accelerating structures use large amounts of electrical energy to accelerate the protons to an energy of 185 MeV. Approximately 60-80% of the electrical energy is dissipated in the copper structure and must be removed. This is done using specifically designed water cooling passages within the linac's copper structure. Cooling water is supplied to these cooling passages by specially designed resonance control and water cooling systems

A digital closed loop control system for automatic phase locking of superconducting cavities of IUAC Linac

International Nuclear Information System (INIS)

Dutt, R.N.; Rai, A.; Pandey, A.; Sahu, B.K.; Patra, P.; Karmakar, J.; Chaudhari, G.K.; Mathur, Y.; Ghosh, S.; Kanjilal, D.

2013-01-01

A closed loop digital control system has been designed and tested to automate the tuning process of superconducting resonators of LINAC at Inter-University Accelerator Centre, New Delhi. The mechanism controls the proportional valves of the He gas based pneumatic tuner in response to the phase and frequency errors of the cavity RF field. The main RF phase lock loop (PLL) is automatically closed once the resonant frequency is within locking range of the resonator PLL. The digital control scheme was successfully tested on few resonators of LINAC cryostat 1. A high stability of phase lock was observed. The details of the digital automation system are presented in the paper. (author)

Nuclear quadrupole-quadrupole interaction in the inelastic scattering of aligned deuterons from deformed nuclei

International Nuclear Information System (INIS)

Clement, H.; Frick, R.; Graw, G.; Schiemenz, P.; Seichert, N.

1983-01-01

The 2 1 + -excitation of deformed nuclei by tensor polarized deuterons provides an alignment of both nuclei and thus a means to study specifically the quadrupole-quadrupole interaction between both nuclei. The tensor analyzing power Asub(xz)(theta) has been measured for the elastic and inelastic scattering on 24 Mg and 28 Si. The coupled channel analysis including a deformed tensor potential reveals a clear signature of the quadrupole-quadrupole part of the nuclear projectile-target interaction. (orig.)

Heavy-ion-linac post-accelerators

International Nuclear Information System (INIS)

Bollinger, L.M.

1979-01-01

The main features of the tandem-linac system for heavy-ion acceleration are reviewed and illustrated in terms of the technology and performance of the superconducting heavy-ion energy booster at Argonne. This technology is compared briefly with the corresponding technologies of the superconducting linac at Stony Brook and the room-temperature linac at Heidelberg. The performance possibilities for the near-term future are illustrated in terms of the proposed extension of the Argonne booster to form ATLAS

Feedback system of the RF phase in KEK-ATF linac

Energy Technology Data Exchange (ETDEWEB)

Okugi, T.; Hayano, H.; Kuriki, M.; Naito, T. [Accelerator Laboratory, High Energy Accelerator Research Organization, Tsukuba, Ibaraki (Japan)

2000-07-01

KEK-ATF linac is built in the Assembly Hall for TRISTAN project in 1991. The thermal condition of the hall is not good enough for a stable linac operation, because the temperature of the klystron gallery is drifted by 1degC within one day. RF phase is also drifted by 3-5deg of the S-band frequency in day and night. In order to control the RF phase, we installed RF phase detectors, which have S/H circuit in order to use for pulsed RF. By using the phase detector, an RF phase feedback system was tested. It was found that a stable klystron operation could be performed within the phase drift of {+-}0.5deg in a day. (author)

The CLIC Test Facility (CTF3) which allowed the first electron beam recombination in order to multiply the RF frequency from 3 GHz up to 15 GHz.

CERN Multimedia

Maximilien Brice

2002-01-01

Photo 0210005_11: The CTF3 linac accelerates an electron beam up to 350 MeV. Photo 0210005_1: At the front, the yellow dipole is used for the spectrometer line. At the back, a doublet of blue quadrupole for the matching. Photo 0210005_03: The CTF3 transfer line between the electron linac and the isochronous ring. Photo 0210005_04: One arc of the EPA isochronous ring. Photo 0210005_06: The CTF3 bunching system. The first RF wave guide feeds the Pre-Buncher while the second RF wave guide feeds the Buncher. They provide a bunched electron beam at 4 MeV. The blue magnet is a solenoid around the Buncher. Photo 0210005_07: A LIL accelerating structure used for CTF3. It is 4.5 meters long and provides an energy gain of 45 MeV. One can see 3 quadrupoles around the RF structure.

Upgrading the Fermilab Linac local control system

International Nuclear Information System (INIS)

McCrory, E.S.; Goodwin, R.W.; Shea, M.F.

1991-02-01

A new control system for the Fermilab Linac is being designed, built and implemented. First, the nine-year-old linac control system is being replaced. Second, a control system for the new 805 MHz part of the linac is being built. The two systems are essentially identical, so that when the installations are complete, we will still have a single Linac Control System. 8 refs., 5 figs

Drift Tube Linac Conditioning of Tank1

CERN Document Server

Shafqat, N; Toor, W A

2014-01-01

Tank1 of the Drift Tube Linac (DTL) of the Linac4 has been conditioned at the Linac4 tunnel. The tank was tuned for resonance at 352.2 MHz, and stable operation has been achieved with 725 µs long RF pulses at a repetition rate of 1 Hz. The maximum RF level that has been reached is 810 kW with a pulse width of 600 µs. Since this was the first RF structure exclusively conditioned in the Linac4 tunnel with the operation and control software of Linac4, some related issues and limitations had to be taken into account.

Simulation of a quadrupole resonator

Energy Technology Data Exchange (ETDEWEB)

Kleindienst, Raphael [Helmholtz Zentrum Berlin (Germany)

2013-07-01

Modern particle accelerators often rely on superconducting radio frequency (SRF) technology for accelerating cavities. In particular in CW operation, very high quality factors up into the high range are desirable, since one of the main cost drivers of such an accelerator, the cryogenic refrigeration plant, is inversely proportional to Q{sub 0}. Present day superconducting cavities are generally made of solid Niobium. A possibility to increase the quality factor as well as accelerating fields is to use thin film coated cavities. Apart from Niobium thin films, other superconducting materials, such as MgB{sub 2}, NbN and Nb{sub 3}Sn are promising candidates. Measuring and understanding the RF-properties of superconducting thin films, specifically the surface resistance, is needed to drive forward this development. Currently only few facilities exist capable of measuring the surface resistance of thin films samples with a resolution in the nano-ohm range at the operating frequency of typical cavities(e.g. L-band). A dedicated test stand consisting of a quadrupole resonator is therefore being constructed at the Helmholtz Zentrum Berlin. This system is based on the 400 MHz quadrupole resonator at CERN, with the design adapted to 433 MHz (making available the higher harmonic mode at 1.3 GHz) and optimized with respect to resolution and maximum achievable fields using simulation data obtained with CST Microwave Studio as well as ANSYS. The simulated design is being manufactured. An outlook for future physics runs is given.

Commissioning plans for SSC linac

International Nuclear Information System (INIS)

Hurd, J.W.; Aprile, R.L.; Chang, C.R.; Crist, C.E.; Cutler, R.I.; Funk, L.W.; Guy, F.W.; Leifeste, G.T.; Raparia, D.; Saadatmand, K.; Sethi, R.C.; Swenson, D.A.; Tooker, J.; Yao, C.G.

1992-01-01

Presented are the general description of the SSC linac and the plans for commissioning. Sections of the linac are installed, tested, and beam commissioned in a serial approach. A specialized set of diagnostics is used to characterize the beam through each section. In addition to the standard diagnostic set, plans call for the use of a bunch shape monitor and x-ray spectrometer. Streak camera and digital imaging diagnostics will be developed. The commissioning plan is folded into the general linac project schedule to show the relation between delivery, staging, installation, conditioning, and actual commissioning with beam. These plans form the basis for coordination between the various organizations responsible for different elements of the linac including the technical components, infrastructure, and temporary staging and operation facilities. (Author) 2 figs., 17 refs

High field electron linacs

International Nuclear Information System (INIS)

Le Duff, J.

1985-12-01

High field electron linacs are considered as potential candidates to provide very high energies beyond LEP. Since almost twenty years not much improvement has been made on linac technologies as they have been mostly kept at low and medium energies to be used as injectors for storage rings. Today, both their efficiency and their performances are being reconsidered, and for instance the pulse compression sheme developed at SLAC and introduced to upgrade the energy of that linac is a first step towards a new generation of linear accelerators. However this is not enough in terms of power consumption and more development is needed to improve both the efficiency of accelerating structures and the performances of RF power sources

The first LHC insertion quadrupole

CERN Multimedia

2004-01-01

An important milestone was reached in December 2003 at the CERN Magnet Assembly Facility. The team from the Accelerator Technology - Magnet and Electrical Systems group, AT-MEL, completed the first special superconducting quadrupole for the LHC insertions which house the experiments and major collider systems. The magnet is 8 metres long and contains two matching quadrupole magnets and an orbit corrector, a dipole magnet, used to correct errors in quadrupole alignment. All were tested in liquid helium and reached the ultimate performance criteria required for the LHC. After insertion in the cryostat, the superconducting magnet will be installed as the Q9 quadrupole in sector 7-8, the first sector of the LHC to be put in place in 2004. Members of the quadrupole team, from the AT-MEL group, gathered around the Q9 quadrupole at its inauguration on 12 December 2003 in building 181.

The Cockcroft-Walton Column

CERN Multimedia

1975-01-01

This 800 kV generator was used for the pe-acceleration of protons before injection into the linear accelerator (LINAC). The Cockcroft-Walton pre-injector was replaced in 1993 by a high intensity radio frequency quadrupole pre-injector. This allowed for higher intensity beams in the later acceleration stages of the CERN accelerator chain.

Quadrupole shunt experiments at SPEAR

International Nuclear Information System (INIS)

Corbett, W.J.; Hettel, R.O.; Nuhn, H.-D.

1996-05-01

As part of a program to align and stabilize the SPEAR storage ring, a switchable shunt resistor was installed on each quadrupole to bypass a small percentage of the magnet current. The impact of a quadrupole shunt is to move the electron beam orbit in proportion to the off-axis beam position at the quadrupole, and to shift the betatron tune. Initially, quadrupole shunts in SPEAR were used to position the electron beam in the center of the quadrupoles. This provided readback offsets for nearby beam position monitors, and helped to steer the photon beams with low-amplitude corrector currents. The shunt-induced tune shift measurements were then processed in MAD to derive a lattice model

Review of superconducting ion linacs

International Nuclear Information System (INIS)

Bollinger, L.M.

1992-01-01

This paper summarizes the status of the technology of superconducting (SC) linacs designed for the acceleration of ions. The emphasis is on the technical issues involved, with only brief descriptions of the numerous linacs now in operation or under construction. Recent developments of special interest are treated in more detail, and remaining technical challenges are outlined. The technology required for the acceleration of ions with velocity β=1 is not discussed because it is almost the same as for relativistic electrons. That is, this paper is mainly about SC linacs for low-velocity heavy ions

Performance of the 100 MeV injector linac for the electron storage ring at Kyoto University

International Nuclear Information System (INIS)

Shirai, T.; Sugimura, T.; Iwashita, Y.; Kakigi, S.; Fujita, H.; Tonguu, H.; Noda, A.; Inoue, M.

1996-01-01

An electron linear accelerator has been constructed as an injector of a 300 MeV electron storage ring (Kaken Storage Ring, KSR) at Institute for Chemical Research, Kyoto University. The output beam energy of the linac is 100 MeV and the designed beam current is 100 mA at the 1 μsec long pulse mode. The transverse and longitudinal emittance are measured to evaluate the beam quality for the beam injection into the KSR. They are observed by the profile monitors combined with quadrupole magnets or an RF accelerator. The results are that the normalized transverse emittance is 120 π.mm.mrad. The longitudinal emittance is 15 π.deg.MeV and the energy spread is ±2.2 %. (author)

Operation of the high-brightness linac for the advanced free-electron laser initiative at Los Alamos

International Nuclear Information System (INIS)

Sheffield, R.L.; Austin, R.H.; Chan, K.C.D.; Gierman, S.M.; Kinross-Wright, J.M.; Kong, S.H.; Nguyen, D.C.; Russell, S.J.; Timmer, C.A.

1993-01-01

Free-electron lasers and high-energy physics accelerators have increased the demand for very high-brightness beam sources. This paper describes the design of an accelerator which has produced beams of 2.1 π mm-mrad at 1 nC and emittances of 3.7 and 6.5 π mm-mrad for 2 and 3 nC, respectively. The accelerator has been operated between 10 and 18 MeV. The beam emittance growth in the accelerator is minimized by using a photoinjector electron source integrated into the design of the linac, a focusing solenoid to correct the emittance growth caused by space charge, and a special design of the coupling slots between accelerator cavities to minimize quadrupole effects. The FEL has recently operated at 5 microns

Operation of the high brightness linac for the advanced free-electron laser initiative at Los Alamos

International Nuclear Information System (INIS)

Sheffield, R.L.; Austin, R.H.; Chan, K.C.D.; Gierman, S.M.; Kinross-Wright, J.M.; Kong, S.H.; Nguyen, D.C.; Russell, S.J.; Timmer, C.A.

1993-01-01

Free-electron lasers and high energy physics accelerators have increased the demand for very high-brightness beam sources. This paper describes the design of an accelerator which has produce beams of less than 2.1 π mm-mrad at 1 nC and emittances of 3.7 and 6.5 π mm-mrad for 2 and 3 nC, respectively. The accelerator has been operated between 10 and 18 MeV.The beam emittance growth in the accelerator is minimized by using a photoinjector electron source integrated into the design of the linac, a focusing solenoid to correct the emittance growth caused by space charge, and a special design of the coupling slots between accelerator cavities to minimize quadrupole effects

A radio frequency quadrupole ion beam buncher for ISOLTRAP

CERN Document Server

Bollen, G; Dezfuli, A M G; Henry, S; Herfurth, F; Kellerbauer, A G; Kim, T; Kluge, H J; Kohl, A; Lamour, E; Lunney, M D; Moore, R B; Quint, W; Schwarz, S; Varfalvy, P; Vermeeren, L

1998-01-01

ISOLTRAP is a Penning trap spectrometer at the on-line mass separator ISOLDE at CERN for the mass determination of radioisotopes. It consists of three electromagnetic traps in tandem; a Paul trap for ISOLDE beam collection, a Penning trap for cooling and purification and a high-precision Penning trap for the measurement of masses by cyclotron resonance. The Paul trap, which collects radionuclide ions using only electric fields and a noble buffer gas, has been essential for the masses of radionuclides that cannot be surface ionized. The success with this system has led to the present program to increase the collection efficiency by replacing the Paul trap by a radiofrequency quadrupole ion guide operating as a buncher. This system would also provide a DC ISOLDE beam of emittance approaching 1$\\pi$ -mm-mrad. (3 refs).

The Fermilab 400-MeV Linac Upgrade

International Nuclear Information System (INIS)

Schmidt, C.W.

1993-05-01

The Fermilab Linac Upgrade will increase the linac energy from 201 MeV to 401.5 MeV. Seven accelerating modules, composed of 805-MHz side-coupled cells, will accelerate H - beams from 116.5 to 401.5 MeV. The side-coupled structure (SCS) has been built, tuned, tested to full power, and placed in the linac enclosure along side the operating Linac. All seven accelerating modules, each containing four sections of sixteen cells, have been connected to 12-MW power klystrons and tested to full power for a significant period. The transition section to match the beam from the 201.25-MHz drift-tube linac to the SCS, consisting of a sixteen-cell cavity and a vernier four-cell cavity, has also been tested at full power. A new import line from the Linac to the Booster synchrotron with a new Booster injection girder is to be installed. Removal of the last four Alvarez linac tanks (116.5 to 201 MeV) and beam-line installation of the Upgrade components is to begin in early June 1993 and should take about 12 weeks. Beam commissioning of the project will follow and normal operation is expected in a short period. In preparation for beam commissioning, studies are being done with done operating linac to characterize the beam at transition and prepare for phase, amplitude and energy measurements to commission the new linac. The past, present and future activities of the 400-MeV Upgrade will be reviewed

Survey of vibration amplitudes throughout the linac

International Nuclear Information System (INIS)

Werner, K.L.

1984-01-01

The magnitude of vibrations of the Linac structure due to on site disturbances, such as cooling towers, pumps, generators, Highway 280 overpass traffic, is of interest. CN-263, for example, discusses tolerances of random (i.e., uncorrelated) quad jitter and suggests that amplitudes should not exceed 0.7 microns rms. This note describes the results of a series of measurements carried out in the summer of 1983. In general, the tolerance is not exceeded, but there appears not to be a good safety factor at low frequencies

Quadrupole shunt experiments at SPEAR

International Nuclear Information System (INIS)

Corbett, W.J.; Hettel, R.O.; Nuhn, H.

1997-01-01

As part of a program to align and stabilize the SPEAR storage ring, a switchable shunt resistor was installed on each quadrupole to bypass a small percentage of the magnet current. The impact of a quadrupole shunt is to move the electron beam orbit in proportion to the off-axis beam position at the quadrupole and to shift the betatron tune. Initially, quadrupole shunts in SPEAR were used to position the electron beam in the center of the quadrupoles. This provided readback offsets for nearby beam position monitors and helped to steer the photon beams with low-amplitude corrector currents. The shunt-induced tune shift measurements were then processed in MAD to derive a lattice model. copyright 1997 American Institute of Physics

Electric quadrupole strength in nuclei

International Nuclear Information System (INIS)

Kirson, M.W.

1979-01-01

Isoscalar electric quadrupole strength distributions in nuclei are surveyed, and it is concluded that the strength is shared, in most cases, roughly equally between low-lying transitions and the giant quadrupole state. The same is not true of the isovector case. A simple extension of the schematic model gives a remarkably successul description of the data, and emphasizes the vital importance of the coupling between high-lying and low-lying quadrupole modes. The standadrd simple representation of the giant quadrupole resonance as produced by operating on the nuclear ground state with the quadrupole transition operator is not applicable to the isoscalar case. It is suggested that giant resonances fall into broad classes of similar states, with considerable qualitative differences between the distinct classes. (author)

Superconducting heavy-ion linac at Argonne

International Nuclear Information System (INIS)

Aron, J.; Benaroya, R.; Bollinger, L.M.; Clifft, B.G.; Johnson, K.W.; Nixon, J.M.; Markovich, P.; Pardo, R.C.; Shepard, K.W.

1981-01-01

The design, status, and performance of the first operating superconducting heavy-ion accelerator, a linac used to boost the energies of beams from a 9-MV tandem, is summarized. When completed in 1981, the linac will consist of 24 independently-phased split-ring niobium resonators operating at 97 MHz. This linac is designed to provide 29 MV of acceleration. Because of the modular character of the system, the linac has been operable and useful since mid-1978, when a beam was accelerated through 2 units and the first nuclear-physics experiments were preformed. Now, 16 resonators are in use, and a beam has been accelerated for approx. 6000 h. Resonator performance has been remarkably stable, in spite of vacuum accidents, and the linac as a whole operates reliably without operators in attendance during nights and weekends. The ease and speed with which the beam energy can be changed is proving to be unexpectedly valuable to users

The trajectory control in the SLC linac

International Nuclear Information System (INIS)

Hsu, I.C.; Adolphsen, C.E.; Himel, T.M.; Seeman, J.T.

1991-05-01

Due to wake field effects, the trajectories of accelerated beams in the Linac should be well maintained to avoid severe beam breakup. In order to maintain a small emittance at the end of the Linac, the tolerance on the trajectory deviations become tighter when the beam intensities increase. The existing two beam trajectory correction method works well when the theoretical model agrees with the real machine lattice. Unknown energy deviations along the linac as well as wake field effects can cause the real lattice to deviate from the model. This makes the trajectory correction difficult. Several automated procedures have been developed to solve these problems. They are: an automated procedure to frequently steer the whole Linac by dividing the Linac into several small regions; an automated procedure to empirically correct the model to fit the real lattice and eight trajectory correcting feedback loops along the linac and steering through the collimator region with restricted corrector strengths and a restricted number of correctors. 6 refs., 2 figs

System engineering in the SSC Linac

International Nuclear Information System (INIS)

Tooker, J.F.; Chang, C.R.; Cutler, R.I.; Funk, L.W.; Guy, F.W.; Hale, R.; Leifeste, G.T.; Nonte, J.; Prichard, B.; Raparia, D.; Saadatmand, K.; Sethi, R.C.; Yao, C.G.

1992-01-01

The design and construction of the SSC Linac involves various departments within the SSCL and many outside vendors. The adaptive incorporation of system engineering principles into the SSC Linac is described. This involves the development of specification trees with the breakdown and flow of functional and physical requirements from the top level system specifications to the lower level component specifications. Interfaces are defined, which specify and control the interconnections between the various components. Review cycles are presented during which the requirements, evolution of the design, and test plans are reviewed, monitored, and finalized. The Linac specification tree, interface definition, and reviews of the Linac are presented, including typical examples. (Author) 2 refs., 3 tabs

Induction-linac based free-electron laser amplifiers for plasma heating

International Nuclear Information System (INIS)

Jong, R.A.

1988-01-01

We describe an induction-linac based free-electron laser amplifier that is presently under construction at the Lawrence Livermore National Laboratory. It is designed to produce up to 2 MW of average power at a frequency of 250 GHz for plasma heating experiments in the Microwave Tokamak Experiment. In addition, we shall describe a FEL amplifier design for plasma heating of advanced tokamak fusion devices. This system is designed to produce average power levels of about 10 MW at frequencies ranging form 280 to 560 GHz. 7 refs., 1 tab

Assessment of the basic parameters of the CERN Superconducting Proton Linac

Directory of Open Access Journals (Sweden)

O. Brunner

2009-07-01

Full Text Available The construction of a 4 GeV superconducting proton linac (the SPL is now part of the long term plan of CERN, and the construction of Linac4, its low-energy front end, has begun. For mid-2012 the existing conceptual design of the SPL has to be refined and transformed into a project proposal. As a first step, basic parameters like rf frequency, accelerating gradient, and operating temperature of the superconducting cavities have been reassessed, taking into account the experience accumulated in the world during the recent years, especially for the Spallation Neutron Source (SNS in Oakridge and the International Linear Collider (ILC projects. The conclusions confirm the validity of the initial choices, namely, the rf frequency of 704.4 MHz and the cooling temperature of ≈2  K. However, the assumed gradients are estimated as optimistic: additional tests are necessary during the coming years to properly define the values to be used in the SPL design. This analysis is documented and its results are explained in this report.

Two-pulse acceleration for BEPCII injector linac

International Nuclear Information System (INIS)

Pei Shilun; Wang Shuhong; Lu Weibin

2007-01-01

In order to double the injection rate of positron beam from the linac to the storage ring of BEPC II, a two-pulse generation and acceleration scheme has been proposed. The two-pulse simulation by programs including LIAR, PARMELA, EGUN and TRANSPORT is described first and the method is applied in the beam dynamics studies of BEPC II linac. The experiment of two-pulse acceleration was performed in BEPC II linac and some preliminary results are obtained, which provides a good reference for further upgrading of BEPC II injector linac. (authors)

The Development of the Linac Coherent Light Source RF Gun

International Nuclear Information System (INIS)

Dowell, D

2008-01-01

The Linac Coherent Light Source (LCLS) is the first x-ray laser user facility based upon a free electron laser (FEL) requiring extraordinary beam quality to saturate at 1.5 angstroms within a 100 meter undulator.[1] This new type of light source is using the last kilometer of the three kilometer linac at SLAC to accelerate the beam to an energy as high as 13.6 GeV and required a new electron gun and injector to produce a very bright beam for acceleration. At the outset of the project it was recognized that existing RF guns had the potential to produce the desired beam but none had demonstrated it. Therefore a new RF gun or at least the modification of an existing gun was necessary. The parameters listed in Table 1 illustrate the unique characteristics of LCLS which drive the requirements for the electron gun as given in Table 2. The gun beam quality needs to accommodate emittance growth as the beam is travels through approximately one kilometer of linac and two bunch compressors before reaching the undulator. These beam requirements were demonstrated during the recent commissioning runs of the LCLS injector and linac [2] due to the successful design, fabrication, testing and operation of the LCLS gun. The goal of this paper is to relate the technical background of how the gun was able to achieve and in some cases exceed these requirements by understanding and correcting the deficiencies of the prototype s-band RF photocathode gun, the BNL/SLAC/UCLA Gun III. This paper begins with a brief history and technical description of Gun III and the Gun Test Facility (GTF) at SLAC, and studies of the gun's RF and emittance compensation solenoid. The work at the GTF identified the gun and solenoid deficiencies, and helped to define the specifications for the LCLS gun. Section 1.1.5 describes the modeling used to compute and correct the gun RF fields and Section 1.1.6 describes the use of these fields in the electron beam simulations. The magnetic design and measurements of

Cea-DSM-DAPNIA-SACM contribution to IFMIF KEP phase June 2000 to December 2002

Energy Technology Data Exchange (ETDEWEB)

NONE

2003-05-01

The international fusion materials irradiation facility (IFMIF) requires the generation by a linear accelerator (LINAC) of 250 mA continuous current of deuterons at a nominal energy of 40 MeV. The basic approach is to provide 2 linac modules, each delivering 125 mA to a common target. The accelerators begin with a deuteron ion source and a low-energy beam transport to a radio-frequency quadrupole (RFQ), a buncher and a pre-accelerator up to 5 MeV. The key element technology phase (KEP) was initiated in 2000 with the objective of reducing some key technology risk factors. The IFMIF KEP is carried out at the Cea and it focuses on 5 issues: the ECR source, the 4-vanes RFQ design, the radio-frequency system, the DTL (drift tube linac) design, and high power diagnostics. The present report reviews progress made in the 5 issues quoted above. (A.C.)

Development of 400- to 450-MHz RFQ resonator-cavity mechanical designs

International Nuclear Information System (INIS)

Hansborough, L.D.

1982-01-01

In the development of the radio-frequency quadrupole (RFQ) linac, the resonator cavity's mechanical design may be a challenge similar in magnitude to that of the development of the accelerator structure itself. Experience with the all-copper 425-MHz RFQ proof-of-principle linac has demonstrated that the resonator cavity must be structurally stiff and easily tunable. This experience has led to development of copper-plated steel structures having vanes that may be moved within a cylinder for tuning. Design of a flexible vane-to-cylinder radio-frequency (rf) joint, the vane, and the cylinder has many constraints dictated by the small-diameter cavities in the 400-MHz-frequency region. Two types of flexible, mechanical vane-to-cylinder rf joints are being developed at Los Alamos: the C-seal and the rf clamp-joint

Preliminary design of a dedicated proton therapy linac

International Nuclear Information System (INIS)

Hamm, R.W.; Crandall, K.R.; Potter, J.M.

1991-01-01

The preliminary design has been completed for a low current, compact proton linac dedicated to cancer therapy. A 3 GHz side-coupled structure accelerates the beam from a 70 MeV drift tube linac using commercially available S-band rf power systems and accelerating cavities. This significantly reduces the linac cost and allows incremental energies up to 250 MeV. The short beam pulse width and high repetition rate make the linac similar to the high energy electron linacs now used for cancer therapy, yet produce a proton flux sufficient for treatment of large tumors. The high pulse repetition rate permits raster scanning, and the small output beam size and emittance result in a compact isocentric gantry design. Such a linac will reduce the facility and operating costs for a dedicated cancer therapy system

Continuous wave superconducting radio frequency electron linac for nuclear physics research

International Nuclear Information System (INIS)

Reece, Charles E.

2016-01-01

CEBAF, the Continuous Electron Beam Accelerator Facility, has been actively serving the nuclear physics research community as a unique forefront international resource since 1995. This cw electron linear accelerator (linac) at the U.S. Department of Energy’s Thomas Jefferson National Accelerator Facility (Jefferson Lab) has continued to evolve as a precision tool for discerning the structure and dynamics within nuclei. Superconducting rf (SRF) technology has been the essential foundation for CEBAF, first as a 4 GeV machine, then 6 GeV, and currently capable of 12 GeV. Lastly, we review the development, implementation, and performance of SRF systems for CEBAF from its early beginnings to the commissioning of the 12 GeV era.

SUPERCONDUCTING LINAC FOR THE SPALLATION NEUTRON SOURCE

International Nuclear Information System (INIS)

STOVALL, J.; NATH, S.

2000-01-01

The Spallation Neutron Source (SNS) linac is comprised of both normal and superconducting rf (SRF) accelerating structures. The SRF linac accelerates the beam from 186 to 1250 MeV through 117 elliptical, multi-cell niobium cavities. This paper describes the SRF linac architecture, physics design considerations, cavity commissioning, and the expected beam dynamics performance

Sci-Thurs PM: Delivery-08: Investigation of the source of RF noise from a modulator for an MR-linac project.

Science.gov (United States)

Lamey, M; Burke, B; Rathee, S; Fallone, B G; Carlone, M

2008-07-01

The next significant step in the advancement of IGRT is the integration of an MRI with a linac. The MRI-linac will provide images with exquisite soft tissue contrast in real-time during treatment. A possible problem associated with the proposed integration is the RF noise generated by the linac. This noise could interfere with the received signals of the MRI producing deleterious effects in the image quality. The work herein is concerned with understanding the processes involved in the RF noise production and the magnitude and frequency of this RF noise in the modulator of a linac. A software programming environment, MultiSIM, was used to model the electronic components of a modulator. Several Current and Voltage waveforms from the modulator were measured with an oscilloscope and compared with the corresponding results from the modulator model for validation. Finally, RF noise generated by the modulator was measured using field probes, which permits the frequency components of the measured and simulated modulator waveforms to be compared with the measured RF noise. The modeled PFN charging current and voltage, and klystron current show good agreement with measurements, with the exception of the tail of the klystron voltage signal. Once the model has been validated in both the time and frequency domains, future work will entail predicting pulse shape changes when, and if, modifications to the modulator are made. Specifically, modifications will be made which shift and/or reduce the RF noise in the frequency range of interest for a 0.2T MRI. © 2008 American Association of Physicists in Medicine.

Just a few metres… but the stakes are high

CERN Multimedia

Caroline Duc

2013-01-01

A beam of negative hydrogen ions has been injected into the first accelerator module of Linac4, the linear accelerator which will replace Linac2.   The Linac4 team celebrate the acceleration of the first beam by the RFQ module. Wednesday, 13 March was a big day for the Linac4 teams. At its temporary location in an old PS hall, the first element in the Linac4 accelerator chain, the Radio Frequency Quadrupole (RFQ) module, accelerated its first beam produced by the new source built for Linac4. This crucial step was a complete success! “Only three metres in length, the RFQ is at the start of the beam's path, immediately after the ion source and the low-energy transport line,” explains Maurizio Vretenar, the Linac4 project leader. “Its job is to increase the beam’s energy from 45 keV to 3 MeV. The section commissioned on Wednesday, which includes the source, the low-energy transport line and the RFQ, is only five metres long but still manages to po...

SPS Quadrupole Magnets

CERN Multimedia

1974-01-01

A stack of SPS Quadrupole Magnets ready for installation in the tunnel. The SPS uses a total of 216 laminated normal conducting lattice quadrupoles with a length of 3.13 m for the core, 3.3 m overall. The F and D quads. have identical characteristics: inscribed circle radius 44 mm, core height and width 800 mm, maximum gradient 20 Tesla/m.

Status and performance of PF injector linac

International Nuclear Information System (INIS)

Sato, Isamu

1994-01-01

PF injector linac has been improved on a buncher section for accelerating of intense electron beam, and reinforced a focusing system of the positron generator linac for the expansion of phase space. In this presentation, I shall report present status and performance of PF injector linac, and discuss its upgrade program for B-factory project. (author)

A microwave power driver for linac colliders gigatron

International Nuclear Information System (INIS)

Bizek, H.M.; Elliott, S.M.; McIntyre, P.M.; Nassiri, A.; Popovic, M.B.; Raparia, D.

1989-01-01

The gigatron is a new rf amplifier tube designed for linac collider applications. Three design features permit extension of the lasertron concept to very high frequencies. First, a gated field-emitter array is employed for the modulated cathode. Second, a ribbon beam geometry mitigates space charge depression and facilitates efficient output coupling. Third, a traveling wave output coupler is used to obtain optimum coupling to the ribbon beam. This paper describes recent developments in the gigatron design, and progress towards experimental tests

Dynamic imperfections and optimized feedback design in the Compact Linear Collider main linac

Directory of Open Access Journals (Sweden)

Peder Eliasson

2008-05-01

Full Text Available The Compact Linear Collider (CLIC main linac is sensitive to dynamic imperfections such as element jitter, injected beam jitter, and ground motion. These effects cause emittance growth that, in case of ground motion, has to be counteracted by a trajectory feedback system. The feedback system itself will, due to jitter effects and imperfect beam position monitors (BPMs, indirectly cause emittance growth. Fast and accurate simulations of both the direct and indirect effects are desirable, but due to the many elements of the CLIC main linac, simulations may become very time consuming. In this paper, an efficient way of simulating linear (or nearly linear dynamic effects is described. The method is also shown to facilitate the analytic determination of emittance growth caused by the different dynamic imperfections while using a trajectory feedback system. Emittance growth expressions are derived for quadrupole, accelerating structure, and beam jitter, for ground motion, and for noise in the feedback BPMs. Finally, it is shown how the method can be used to design a feedback system that is optimized for the optics of the machine and the ground motion spectrum of the particular site. This feedback system gives an emittance growth rate that is approximately 10 times lower than that of traditional trajectory feedbacks. The robustness of the optimized feedback system is studied for a number of additional imperfections, e.g., dipole corrector imperfections and faulty knowledge about the machine optics, with promising results.

Dynamic imperfections and optimized feedback design in the Compact Linear Collider main linac

Science.gov (United States)

Eliasson, Peder

2008-05-01

The Compact Linear Collider (CLIC) main linac is sensitive to dynamic imperfections such as element jitter, injected beam jitter, and ground motion. These effects cause emittance growth that, in case of ground motion, has to be counteracted by a trajectory feedback system. The feedback system itself will, due to jitter effects and imperfect beam position monitors (BPMs), indirectly cause emittance growth. Fast and accurate simulations of both the direct and indirect effects are desirable, but due to the many elements of the CLIC main linac, simulations may become very time consuming. In this paper, an efficient way of simulating linear (or nearly linear) dynamic effects is described. The method is also shown to facilitate the analytic determination of emittance growth caused by the different dynamic imperfections while using a trajectory feedback system. Emittance growth expressions are derived for quadrupole, accelerating structure, and beam jitter, for ground motion, and for noise in the feedback BPMs. Finally, it is shown how the method can be used to design a feedback system that is optimized for the optics of the machine and the ground motion spectrum of the particular site. This feedback system gives an emittance growth rate that is approximately 10 times lower than that of traditional trajectory feedbacks. The robustness of the optimized feedback system is studied for a number of additional imperfections, e.g., dipole corrector imperfections and faulty knowledge about the machine optics, with promising results.

Full three-dimensional approach to the design and simulation of a radio-frequency quadrupole

Directory of Open Access Journals (Sweden)

B. Mustapha

2013-12-01

Full Text Available We have developed a new full 3D approach for the electromagnetic and beam dynamics design and simulation of a radio-frequency quadrupole (RFQ. A detailed full 3D model including vane modulation was simulated, which was made possible by the ever advancing computing capabilities. The electromagnetic (EM design approach was first validated using experimental measurements on an existing prototype RFQ and more recently on the actual full size RFQ. Two design options have been studied, the original with standard sinusoidal modulation over the full length of the RFQ; in the second design, a trapezoidal modulation was used in the accelerating section of the RFQ to achieve a higher energy gain for the same power and length. A detailed comparison of both options is presented supporting our decision to select the trapezoidal design. The trapezoidal modulation increased the shunt impedance of the RFQ by 34%, the output energy by 15% with a similar increase in the peak surface electric field, but practically no change in the dynamics of the accelerated beam. The beam dynamics simulations were performed using three different field methods. The first uses the standard eight-term potential to derive the fields, the second uses 3D fields from individual cell-by-cell models, and the third uses the 3D fields for the whole RFQ as a single cavity. A detailed comparison of the results from TRACK shows a very good agreement, validating the 3D fields approach used for the beam dynamics studies. The EM simulations were mainly performed using the CST Microwave-Studio with the final results verified using other software. Detailed segment-by-segment and full RFQ frequency calculations were performed and compared to the measured data. The maximum frequency deviation is about 100 kHz. The frequencies of higher-order modes have also been calculated and finally the modulation and tuners effects on both the frequency and field flatness have been studied. We believe that with

Linac4 crosses the 100 MeV threshold

CERN Multimedia

Corinne Pralavorio

2016-01-01

The new linear accelerator, which from 2020 will be the first link in the accelerator chain, has entered a new stage of its commissioning.   Members of the team in charge of the commissioning of Linac4 in the accelerator’s control room. A few hours earlier, Linac4 accelerated a beam to 107 MeV for the first time. We couldn’t have imagined a more appropriate date: on 1 July (1.07), Linac4 reached an energy of 107 MeV. Having crossed the 100 MeV barrier, the linear accelerator is now on the home straight of its commissioning. “This stage was very quick – it took less than two weeks,” says Alessandra Lombardi, deputy project leader of Linac4, in charge of the commissioning. In 2020, Linac4 will replace the existing Linac2 as the first link in the accelerator chain. It will accelerate beams of H- ions (protons surrounded by two electrons) to 160 MeV, compared to 50 MeV with Linac2. The new machine is particularly sophisticated as it comprises...

Simulations of the Static Tuning for the TESLA Linear Collider

CERN Document Server

Schulte, Daniel

2003-01-01

At the heart of the TESLA linear collider are the two 10 km long superconducting linacs. A linac is constructed from 858 cryomodules each containing 12 nine-cell 1.3 GHz superconducting cavities. 355 quadrupoles provide the necessary beam focusing. The advantages of low-frequency superconducting RF in terms of wakefield behaviour are well known, and the TESLA alignment tolerances are relatively loose. However, the effects of cavity tilts and their impact of the linac beam-based alignment algorithms have until recently not been fully investigated. In addition, the strong sensitivity to correlated emittance growth due to the high beam-beam disruption parameter makes it desirable to control the linac emittance down to a few percent. In this report we discuss various static tuning algorithms and present new simulation results. Discussions of the relative merits and applicability of the methods is also discussed.

TOP LINAC design

International Nuclear Information System (INIS)

Picardi, L.; Ronsivalle, C.; Vignati, A.

1997-11-01

The report describes a linear accelerator for protons named TOP LINAC designed for the TOP (Terapia Oncologica con Protoni, Oncological Protontherapy) project launched by the Italian National Institute of Health (Istituto Superiore di Sanita', ISS) to explore in collaboration with the biggest Oncological Hospital in Rome (Istituto Regina Elena, IRE) the potentialities of the therapy with accelerated protons and establish guide lines for the application of this new type of radiotherapy in comparison with the more traditional electron and x-rays radiotherapy. The concept of a compact accelerator for protontherapy applications bore within the Italian Hadrontherapy Collaboration (TERA Collaboration) with the aim to diffuse the protontherapy on the National territory. The ISS program plans to use the TOP linac proton beam also for production of PET (Positron Emission Tomography) radioisotopes and radiobiology studies. Official agreements are in course between ISS and ENEA which provides its experience in the industrial and medical accelerators for the design and the construction of the TOP linac. The accelerator that will be the first 3 GHz proton linac in the world, will be composed of a 428.3 MHz 7 Me V RFQ + DTL injector followed by a 7-65 Me V section of a 3 GHz SCDTL structure and a 65 - 200 Me V variable energy SCL 3 GHz structure. In particular the SCDTL section uses a highly innovative accelerating structure patented by ENEA. In this report the clinical and physical requests are discussed and a preliminary design of the whole machine is given

All Digital IQ Servo-System for CERN Linacs

CERN Document Server

Rohlev, A; Garoby, R

2003-01-01

A new VME based system has been developed and built at CERN for the servo loops regulating the field in the linac accelerating structure. It makes use of high speed digital In-phase/Quadrature (IQ) detection, digital processing, and digital IQ modulation. The digital processing and IQ modulation is done in a single PLD. The system incorporates continually variable set points, iterative learning, feed forward as well as extensive diagnostics and other features well suited for digital implementations. Built on a single VME card, it will be first used in the energy ramping RF chain of the CERN Heavy Ion Linac (linac 3) and later for upgrading the present proton linac (linac 2). This system serves also as a prototype for the future Superconducting Proton Linac (SPL). The design principle and the experimental results are described.

Measurement of intense coherent synchrotron radiation at frequencies around 0.1 THz using the compact S-band linac

International Nuclear Information System (INIS)

Sei, Norihiro; Kuroda, Ryunosuke; Yasumoto, Masato; Toyokawa, Hiroyuki; Ogawa, Hiroshi; Koike, Masaki; Yamada, Kawakatsu

2008-01-01

We measured intense radiation from an electron bunch in a millimeter wave region using the compact S-band linac. The dependence of the radiation on the electron-bunch charge was measured with an rf detector system at frequencies around 0.1 THz and was confirmed to be a coherent synchrotron radiation (CSR). The total power of the horizontally and vertically polarized CSRs, which were extracted through the Z-cut quartz window within 1 ns, was calculated to be about 88 and 30 nJ/pulse, excluding the absorption by the window. The two-dimensional distribution of the vertically polarized CSR was measured at a distance of about 0.7 m from the radiation point. The CSR distribution was comparatively uniform in the horizontal plane. Intense CSR, which was reflected in the vacuum chamber, was extracted with a delay of about 6 ns. This suggests that measurement of temporal structure is needed for CSR applications

CLIC Quadrupole Module final report

CERN Document Server

Artoos, K; Mainaud-Durand, H

2013-01-01

Future Linear colliders will need particle beam sizes in the nanometre range. The beam also needs to be stable all along the beam line. The CLIC Main Beam Quadrupole (MBQ) module has been defined and studied. It is meant as a test stand for stabilisation and pre-alignment with a MB Quadrupole. The main topic that has been tackled concerns the Quadrupole magnet stabilisation to 1nm at 1Hz. This is needed to obtain the desired CLIC luminosity of 2.1034 cm-2m-1. The deliverable was demonstrated by procuring a MBQ and by stabilising a powered and cooled CLIC MBQ quadrupole. In addition, the stabilisation system has to be compatible with the pre-alignment procedures. Pre-alignment movement resolution has been demonstrated to 1m. The last step is the combined test of stability with a quadrupole on a CLIC Module with the pre-alignment.

Macroscopic description of normal quadrupole oscillations and shape of rotating nuclei (spheroids)

International Nuclear Information System (INIS)

Balbutsev, E.B.; Mikhailov, I.N.; Vaishvila, Z.

1981-01-01

The ''distorted-Fermi-surface'' model is generalized to study the rotating nuclei. The mathematical problems of the model are solved with the help of the tensor virial method by Chandrasekhar-Lebovitz. The parameters of a form and characteristic frequencies of the quadrupole oscillations are calculated as a function of angular velocity Ω for the rotating nuclei. The energy of Giant Quadrupole Resonance is in agreement with experiment for Ω=0. There are two low-lying modes of oscillations in the model. The critical angular momenta are calculated. The comparison with the liquid drop model is done [ru

Sawtooth-wave prebuncher with dual-gaps in Linac injector for HIRFL-SSC

Science.gov (United States)

Zhang, Xiaohu; Yuan, Youjin; Xia, Jiawen; Yin, Xuejun; Jin, Peng; Xu, Zhe; Du, Heng; Li, Zhongshan; Qiao, Jian; Wang, Kedong

2018-01-01

An RFQ structure is normally composed of radial matcher, shaper, gentle buncher and accelerator section with changing cell geometry. Bunching is started in the shaper, and adiabatic bunching is done in gentle buncher section. The beam preforms from DC beam to bunch beam through the RFQ and the longitudinal emittance for the ions linacs is defined initially in the RFQ, in which the beam bunch has been shaped. In the present SSC-Linac injector, an RFQ has been designed to accelerate the continuous beam from 3.728 keV/u to 143 keV/u. The heavy ions beam is injected into the SSC (Separated Sector Cyclotron) with the kinetic energy of 1.025 MeV/u after four IH DTLs. The rf frequency of the SSC is 13.417 MHz, and the frequency of the heavy ions RFQ is set to four times of the rf frequency of the SSC. In order to increase the longitudinal capture efficiency of the SSC and suppress the longitudinal emittance at the exit of RFQ, an external MHB (Multi-Harmonics Buncher) is proposed in front of the RFQ. The fundamental frequency of the MHB is the same as the rf frequency of the cyclotron. The scheme of dual-gaps prebuncher with the sawtooth waveform is firstly carried out through multi-harmonics synthetic technology. The multi-particle beam dynamic simulations of the MHB have been done by the BEAMPATH code.

Radiotechnical Institute activity in the linac field

International Nuclear Information System (INIS)

Murin, B.P.

1976-01-01

For many years, the Radiotechnical Institute has been involved in a number of projects aimed at constructing linear accelerators for protons or electrons. This report summarizes the experience gained and covers 1) some problems of developing linacs to serve as meson or neutron generators, 2) results of study of a linac with asymmetric alternating phase focusing, and 3) electron linac projects. (author)

IMPACT simulation and the SNS linac beam

International Nuclear Information System (INIS)

Zhang, Y.; Qiang, J.

2008-01-01

Multi-particle tracking simulations for the SNS linac beam dynamics studies are performed with the IMPACT code. Beam measurement results are compared with the computer simulations, including beam longitudinal halo and beam losses in the superconducting linac, transverse beam Courant-Snyder parameters and the longitudinal beam emittance in the linac. In most cases, the simulations show good agreement with the measured results

The application of RFQs

International Nuclear Information System (INIS)

Schempp, A.

1992-01-01

The Radio Frequency Quadrupole Accelerator (RFQ) has found wide application, not only as the preinjector linac for new high energy light ion accelerators but also in a variety of other projects. Progress in development has made ion linacs practical for medical and industrial applications including radiation therapy, isotope and neutron production, material modification and ion beam diagnostic. The paper discusses various projects together with applications in science where RFQs serve as stand-alone tools, for example for the calibration of detectors, as decelerators or as small compact beam sources for atomic physics and materials research. (Author) 7 figs., 40 refs

A superconducting RFQ for an ECR injector

International Nuclear Information System (INIS)

Ben-Zvi, I.

1988-01-01

The beam dynamics and resonator properties of a superconducting radio-frequency quadrupole (RFQ) for heavy ions are discussed. The motivation is its use as a very low velocity section following an electron cyclotron resonance (ECR) source for injection into a superconducting heavy-ion linac. The constraints on the design and performance of this accelerating structure are presented. Expressions for a limiting stable phase angle and longitudinal and transverse acceptance are derived. A numerical example is given, using the SUNYLAC linac at Sony Stony Brook. Beam-dynamics calculations with PARMTEQ are reported, verifying the theoretical beam-dynamics calculations. (author) 12 refs., 1 tab

Proton induction linacs as high-intensity neutron sources

International Nuclear Information System (INIS)

Keefe, D.; Hoyer, E.

1981-01-01

Proton induction linacs are explored as high intensity neutron sources. The induction linac - concept, properties, experience with electrons, and possibilities - and its limitations for accelerating ions are reviewed. A number of proton induction linac designs are examined with the LIACEP program and general conclusions are given. Results suggest that a proton induction accelerator of the lowest voltage, consistent with good neutron flux, is preferred and could well be cost competitive with the usual rf linac/storage ring designs. (orig.)

25 years of Pelletron Linac facility

International Nuclear Information System (INIS)

Shrivastava, A.; Palit, R.

2014-01-01

The DAE-BRNS International Symposium on Nuclear Physics was held in BARC during 2nd to 6th December 2013. A summary of the highlights of this symposium has recently appeared in Physics News. As a part of the symposium, a special session was held to commemorate 25 years of operation of the Mumbai Pelletron Linac Facility (PLF). PLF, being operated jointly by Bhabha Atomic Research Centre and Tata Institute of Fundamental Research, has been a major centre for heavy-ion accelerator based research in India. The Pelletron accelerator was formally inaugurated on 30th December 1988, and marked an important milestone in nuclear physics research in India. The facility was augmented with the indigenously developed superconducting LINAC booster to enhance the energy of the accelerated beams. The LINAC booster was commissioned in a phased manner and the entire facility was dedicated to the users on the 28th November 2007. The LINAC booster consists of seven liquid helium cryostat modules, each housing four lead coated (2 μm) copper quarter wave resonators (QWR). The cavities are designed to operate at 150 MHz with an optimum acceptance at a velocity corresponding to β=0.1. The performance of the QWRs is found to be excellent with an average energy gain of 0.4 MV/q per cavity corresponding to 80% of the design value. Beam transmission from the entry to the exit of the LINAC was found to be 80% and the beam timing (FWHM) of 600 ps was measured at the target position. Development of the superconducting LINAC is a major milestone in the accelerator technology in our country. Most of the critical components of the LINAC booster, the first superconducting heavy-ion accelerator in India, have been designed, developed and fabricated indigenously

Continuous wave superconducting radio frequency electron linac for nuclear physics research

Directory of Open Access Journals (Sweden)

Charles E. Reece

2016-12-01

Full Text Available CEBAF, the Continuous Electron Beam Accelerator Facility, has been actively serving the nuclear physics research community as a unique forefront international resource since 1995. This cw electron linear accelerator (linac at the U.S. Department of Energy’s Thomas Jefferson National Accelerator Facility (Jefferson Lab has continued to evolve as a precision tool for discerning the structure and dynamics within nuclei. Superconducting rf (SRF technology has been the essential foundation for CEBAF, first as a 4 GeV machine, then 6 GeV, and currently capable of 12 GeV. We review the development, implementation, and performance of SRF systems for CEBAF from its early beginnings to the commissioning of the 12 GeV era.

A large-aperture, low-resolution quadrupole separator for producing deposited cluster materials

CERN Document Server

Denby, P M

2000-01-01

A wide-aperture, low-resolution quadrupole separator for metal clusters is described. Its performance has been evaluated by numerical calculations of the trajectories of clusters. Operating in the frequency range from 5 to 100 KHz allows one to separate clusters in the mass range from 30000 to 300000 AMU and by suitable choice of the AC and DC voltages one can obtain a resolution of 0.15. At this resolution the transmission of clusters from a source is 100% over the selected mass range. By biasing the quadrupole it has been possible to obtain a very sharp cut-off between the transmitted clusters and those outside the selected range. Trajectory calculation for clusters deposited onto a biased 2 cm diameter substrate show that it is possible to keep the deposition energy below 25 eV for 90% of the clusters when the quadrupole is itself biased.

A large-aperture, low-resolution quadrupole separator for producing deposited cluster materials

Energy Technology Data Exchange (ETDEWEB)

Denby, P.M.; Eastham, D.A. E-mail: d.a.eastham@dl.ac.uk

2000-03-01

A wide-aperture, low-resolution quadrupole separator for metal clusters is described. Its performance has been evaluated by numerical calculations of the trajectories of clusters. Operating in the frequency range from 5 to 100 KHz allows one to separate clusters in the mass range from 30000 to 300000 AMU and by suitable choice of the AC and DC voltages one can obtain a resolution of 0.15. At this resolution the transmission of clusters from a source is 100% over the selected mass range. By biasing the quadrupole it has been possible to obtain a very sharp cut-off between the transmitted clusters and those outside the selected range. Trajectory calculation for clusters deposited onto a biased 2 cm diameter substrate show that it is possible to keep the deposition energy below 25 eV for 90% of the clusters when the quadrupole is itself biased.

A large-aperture, low-resolution quadrupole separator for producing deposited cluster materials

International Nuclear Information System (INIS)

Denby, P.M.; Eastham, D.A.

2000-01-01

A wide-aperture, low-resolution quadrupole separator for metal clusters is described. Its performance has been evaluated by numerical calculations of the trajectories of clusters. Operating in the frequency range from 5 to 100 KHz allows one to separate clusters in the mass range from 30000 to 300000 AMU and by suitable choice of the AC and DC voltages one can obtain a resolution of 0.15. At this resolution the transmission of clusters from a source is 100% over the selected mass range. By biasing the quadrupole it has been possible to obtain a very sharp cut-off between the transmitted clusters and those outside the selected range. Trajectory calculation for clusters deposited onto a biased 2 cm diameter substrate show that it is possible to keep the deposition energy below 25 eV for 90% of the clusters when the quadrupole is itself biased

10 MeV RF electron linac for industrial applications

International Nuclear Information System (INIS)

2017-01-01

Electron linacs have found numerous applications in the field of radiation processing on an industrial scale. High power RF electron linacs are commonly used for food irradiation, medical sterilization, cross-linking of polymers, etc. For this purpose, the 10 MeV RF linac has been indigenously designed, developed, commissioned and is being used regularly at 3 kW beam power. This paper gives a brief description of the linac and its utilization for various applications. Safety considerations and regulatory aspects of the linac are also discussed

Update of the Linac4-PSB Transfer Line

CERN Document Server

HEIN, Lutz

2010-01-01

The installation of Linac4 represents the first step of the upgrade plans of the CERN accelerator complex for the future in order to raise the available proton flux to attain amongst others the LHC ultimate luminosity. This linac is capable to accelerate H--ions from 45keV to 160MeV, which will be injected into the Proton Synchrotron Booster (PSB). The increase of energy from 50MeV (Linac2) to 160MeV (Linac4) allows to overcome the space charge limitations at the PSB injection, which is the main bottleneck towards higher beam brightness in the downstream accelerator chain. In order to preserve beam quality from the outlet of Linac4 to PSB injection the design of the transfer line becomes crucial. As the location of Linac4 was chosen in view of upgrade scenarios, the construction of a new transfer line is foreseen, see ref.[1] and ref.[2]. Here part of the Linac2-PSB transfer line will be re-used. In the new part of the transfer line the beam is horizontally and vertically adjusted towards the bending magnet B...

Wire alignment system for ATF LINAC

International Nuclear Information System (INIS)

Hayano, H.; Takeda, S.; Matsumoto, H.; Matsui, T.

1994-01-01

A wire based alignment system is adopted to make less than 40μm precision alignment for injector linac of Accelerator Test Facility (ATF). The system consists of two stretched SUS wires, pickup coils and active mover stages. The position of pickup coils in a mount which will be installed into LINAC stages is set to the calculated wire position prior to installation. All of LINAC stages are then moved to keep the calculated position by the active mover. The test results of wire position detection in a long term are described. (author)

Application of RF Superconductivity to High-Current Linac

International Nuclear Information System (INIS)

Chan, K.C.D.

1998-01-01

In 1997, the authors initiated a development program in Los Alamos for high-current superconducting proton-linac technology to build prototypes components of this linac to demonstrate the feasibility. The authors are building 700-MHz niobium cavities with elliptical shapes, as well as power couplers to transfer high RF power to these cavities. The cavities and power couplers will be integrated in cryostats as linac cryomodules. In this paper, they describe the linac design and the status of the development program

A Faraday Cup with high frequency response for a 200 MeV LINAC proton beam

International Nuclear Information System (INIS)

Zucker, M.S.; Bittner, J.W.

1991-01-01

The purpose of this device, composed essentially of coaxial line elements, is monitoring, on a per micropulse basis, the beam intensity of a 200 MeV LINAC at the BNL Radiation Effects Facility. The center conductor of the coaxial line acts as a beam stop. The output pulses are suitable for fast timing. 2 refs., 5 figs

MQXFS1 Quadrupole Design Report

Energy Technology Data Exchange (ETDEWEB)

Ambrosio, Giorgio [Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States); et al.

2016-04-14

This report presents the reference design of MQXFS1, the first 1.5 m prototype of the low-beta quadrupoles (MQXF) for the LHC High Luminosity Upgrade. The MQXF quadrupoles have 150 mm aperture, coil peak field of about 12 T, and use $Nb_{3}Sn$ conductor. The design is based on the LARP HQ quadrupoles, which had 120 mm aperture. MQXFS1 has 1st generation cable cross-section and magnetic design.

S-band linac-based X-ray source with {pi}/2-mode electron linac

Energy Technology Data Exchange (ETDEWEB)

Deshpande, Abhay, E-mail: abhay@post.kek.jp [Department of Accelerator Science, School of High Energy Accelerator Science, Graduate University for Advanced Studies, Shonan International Village, Hayama, Miura, Kanagawa 240-0193 (Japan); Society for Applied Microwave Electronic Engineering and Research (SAMEER), R and D Laboratory of the Government of India, IIT Campus, Powai, Mumbai 400 076 (India); Araki, Sakae [High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Dixit, Tanuja [Society for Applied Microwave Electronic Engineering and Research (SAMEER), R and D Laboratory of the Government of India, IIT Campus, Powai, Mumbai 400 076 (India); Fukuda, Masafumi [High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Krishnan, R; Pethe, Sanjay [Society for Applied Microwave Electronic Engineering and Research (SAMEER), R and D Laboratory of the Government of India, IIT Campus, Powai, Mumbai 400 076 (India); Sakaue, Kazuyuki [Waseda University, Shinjuku-ku, Tokyo 169-8555 (Japan); Terunuma, Nobuhiro; Urakawa, Junji [High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Washio, Masakazu [Waseda University, Shinjuku-ku, Tokyo 169-8555 (Japan)

2011-05-01

The activities with the compact X-ray source are attracting more attention, particularly for the applications of the source in medical fields. We propose the fabrication of a compact X-ray source using the SAMEER electron linear accelerator and the KEK laser undulator X-ray source (LUCX) technologies. The linac developed at SAMEER is a standing wave side-coupled S-band linac operating in the {pi}/2 mode. In the proposed system, a photocathode RF gun will inject bunches of electrons in the linac to accelerate and achieve a high-energy, low-emittance beam. This beam will then interact with the laser in the laser cavity to produce X-rays of a type well suited for various applications. The side-coupled structure will make the system more compact, and the {pi}/2 mode of operation will enable a high repetition rate operation, which will help to increase the X-ray yield.

Bringing up beams

CERN Multimedia

Katarina Anthony

2013-01-01

Last month, commissioning began on CERN’s newest linear accelerator: Linac4. As the replacement machine for Linac2, Linac4 will take a negative hydrogen ion beam to a staggering 160 MeV. We check in to see how the Linac4 team is preparing its machine for its new role as the first link in the accelerator chain.   The Linac4 3 MeV beam line, with the ion source in the back, the RFQ in the middle and the chopping line in the front. On 14 November, members of the Linac4 collaboration and the CERN Operations Group were brought together for their first “real day” in the Linac4 Control Room. Together, they successfully accelerated their first hydrogen ion beam to 3 MeV. It was an exciting moment for everyone involved and marked the start of one of the most critical commissioning phases for the new accelerator. At the start of the Linac4 beam line sits the CERN-made Radio Frequency Quadrupole (RFQ). This vital piece of machinery takes the beam from 45 keV to 3 MeV in ju...

Transistor regenerative spectrometer for 14N nuclear quadrupole resonance study

International Nuclear Information System (INIS)

Anferov, V.P.; Mikhal'kov, V.M.

1981-01-01

Improvement of the Robinson transducer for investigations of nuclear quadrupole resonance (NQR) in 14 N is described. Amplifier of the suggested transducer is made using p-n field effect transistor and small-noise SHF bipolar transistor. Such a circuit permits to obtain optimal relation between input resistance, low-frequency noises and transconductance which provides uniform gain of the transducer in the frequency range of 0.6-12 MHz and permits to construct a transistor spectrometer of NQR not yielding to a lamp spectrometer in sensitivity [ru

First Linac4 DTL & CCDTL cavities installed in tunnel

CERN Multimedia

Katarina Anthony

2014-01-01

On 5 June, the first Drift Tube Linac (DTL) was successfully transported to its forever home in the Linac4 tunnel. Similarly, the first Cell-Coupled Drift Tube Linac (CCDTL) was installed on 6 June. These moves marked the end of years of design and manufacturing by Linac4 teams.   Although it may seem like a relatively routine transport operation, the DTL's move was a landmark event for the entire Linac4 collaboration. "Along with the first four Cell-Coupled DTL modules, which were installed on the following two working days, these are the first accelerating structures after front-end commissioning to be installed in the tunnel," says Frank Gerigk, who is responsible for all Linac4 accelerating structures. "It is a major milestone, because work on all these structures started well over a decade ago." The transport operation was also quite a victory for the Linac4 DTL team, whose journey to a complete DTL structure has been a bit of a wild ride. &qu...

Achromatic beam transport of High Current Injector

International Nuclear Information System (INIS)

Kumar, Sarvesh; Mandal, A.

2016-01-01

The high current injector (HCI) provides intense ion beams of high charge state using a high temperature superconducting ECR ion source. The ion beam is accelerated upto a final energy of 1.8 MeV/u due to an electrostatic potential, a radio frequency quadrupole (RFQ) and a drift tube linac (DTL). The ion beam has to be transported to superconducting LINAC which is around 50 m away from DTL. This section is termed as high energy beam transport section (HEBT) and is used to match the beam both in transverse and longitudinal phase space to the entrance of LINAC. The HEBT section is made up of four 90 deg. achromatic bends and interconnecting magnetic quadrupole triplets. Two RF bunchers have been used for longitudinal phase matching to the LINAC. The ion optical design of HEBT section has been simulated using different beam dynamics codes like TRACEWIN, GICOSY and TRACE 3D. The field computation code OPERA 3D has been utilized for hardware design of all the magnets. All the dipole and quadrupole magnets have been field mapped and their test results such as edge angles measurements, homogeneity and harmonic analysis etc. are reported. The whole design of HEBT section has been performed such that the most of the beam optical components share same hardware design and there is ample space for beam diagnostics as per geometry of the building. Many combination of achromatic bends have been simulated to transport the beam in HEBT section but finally the four 90 deg. achromatic bend configuration is found to be the best satisfying all the geometrical constraints with simplified beam tuning process in real time

Development of an Eddy Current Septum for LINAC4

CERN Document Server

Barnes, M; Borburgh, J; Fowler, T; Goddard, B; Ueda, A; Weterings, W

2008-01-01

A linear accelerator (linac) is the first stage of the CERN accelerator complex. The linac defines the beam quality for subsequent stages of acceleration and the reliability has to be high as a fault of the linac shuts down all other machines. The existing linacs at CERN were designed 30 or more years ago: recent upgrades allowed the linacs to reach LHC requirements but also showed that they are at the limit of their brightness and intensity capabilities. A replacement Superconducting Proton Linac (SPL) has been proposed; the initial part of the SPL is termed LINAC4. The LINAC4 injection bump would be made up of a set of four pulsed dipole magnets; the first of these magnets (BS1) must act as a septum with a thin element dividing the high-field region of the circulating beam from the field-free region through which injected $H^{-}$ beam must pass. The initial specifications for BS1 required; a deflection of 66 mrad at 160 MeV, achieved with a peak field of 628 mT and a length of 250 mm: the field fall time wa...

Centering of quadrupole family

International Nuclear Information System (INIS)

Pinayev, Igor

2007-01-01

A procedure for finding the individual centers for a family of quadrupoles fed with a single power supply is described. The method is generalized for using the correctors adjacent to the quadrupoles. Theoretical background is presented as well as experimental data for the NSLS rings. The method accuracy is also discussed

Ion trajectories quadrupole mass filters

International Nuclear Information System (INIS)

Ursu, D.; Lupsa, N.; Muntean, F.

1994-01-01

The present paper aims at bringing some contributions to the understanding of ion motion in quadrupole mass filters. The theoretical treatment of quadrupole mass filter is intended to be a concise derivation of the important physical relationships using Mathieu functions. A simple iterative method of numerical computation has been used to simulate ion trajectories in an ideal quadrupole field. Finally, some examples of calculation are presented with the aid of computer graphics. (Author) 14 Figs., 1 Tab., 20 Refs

All Digital IQ Servo-System for CERN Linacs

CERN Document Server

Broere, J; Garoby, R; Rohlev, A; Serrano, J

2004-01-01

A VME based control system has been developed and built at CERN for the servo loops regulating the field in linac accelerating structures. It is an all-digital system built on a single VME card, providing digital detection, processing, and modulation. It is foreseen to be used, in different versions, for the needs of both present and future CERN hadron linacs. The first application will be in the energy ramping RF chain of the CERN Heavy Ion Linac (linac 3). Design principle and the experimental results are described.

Upgrade of the controls for the Brookhaven linac

International Nuclear Information System (INIS)

Buxton, W.E.

1995-01-01

The control of the magnets, rf system, and other components at the Brookhaven Linac uses a system that was developed at Brookhaven in the late 1960's. This system will be retired in the summer of 1995. The Linac controls are being upgraded using modem VME-based hardware compatible with RHIC generation controls, and an existing serial field bus. The timing for the Linac will also be upgraded and will use components developed for RHIC. The controls in general, the timing for the Linac, and the modules developed will be described

Emittance variations in current-amplifying ion induction linacs

International Nuclear Information System (INIS)

Fessenden, T.J.

1991-01-01

Since 1985 the Heavy Ion Fusion Accelerator Research program at the Lawrence Berkeley Laboratory has been studying current amplification and emittance variations in MBE-4, a four-cesium-beam induction linac. This experiment models much of the accelerator physics of the electrostatically focused section of a fusion driver. Four space-charge dominated Cs + beams, initially about one meter in length at currents of 5-10 mA, are focused by electrostatic quadrupoles and accelerated in parallel from approximately 200 keV up to one MeV by 24 accelerating gaps. Final currents of 20-40 mA per beam are typical. Recent experiments with extremely low emittance beams (var-epsilon n =0.03 mm-mRad) have investigated variations of transverse and longitudinal normalized emittance for drifting and accelerating beams. These very strongly tune-depressed beams (σ 0 =72 degree, σ∼6 degree) are difficult to match to the accelerator so as to avoid emittance growth during acceleration. During transport strong emittance fluctuations are observed in good qualitative agreement with simulations. Warmer beams with less tune depression exhibit little to no emittance growth, show smaller emittance fluctuations, and are much easier to match. A summary of findings from the MBE-4 studies is presented

Emittance variations in current-amplifying ion induction linacs

International Nuclear Information System (INIS)

Fessenden, T.J.

1991-04-01

Since 1985 the Heavy Ion Fusion Accelerator Research program at the Lawrence Berkeley Laboratory has been studying current amplification and emittance variations in MBE-4, a four-cesium-beam induction linac. This experiment models much of the accelerator physics of the electrostatically focused section of a fusion driver. Four space-charge dominated Cs + beams, initially about one meter in length at currents of 5--10 mA, are focused by electrostatic quadrupoles and accelerated in parallel from approximately 200 keV up to one MeV by 24 accelerating gaps. Final currents of 20--40 mA per beam are typical. Recent experiments with extremely low emittance beams (ε n = 0.03 mm-mRad) have investigated variations of transverse and longitudinal normalized emittance for drifting and accelerating beams. These very strongly tune-depressed beams (σ o = 72 degrees, σ∼6 degree) are difficult to match the accelerator so as to avoid emittance growth during acceleration. During transport strong emittance fluctuations are observed in good qualitative agreement with simulations. Warmer beams with less tune depression exhibit little to no emittance growth, show smaller emittance fluctuations, and are much easier to match. A summary of findings from the MBE-4 studies is presented. 12 refs., 8 figs

Beam dynamics simulation of the Spallation Neutron Source linear accelerator

International Nuclear Information System (INIS)

Takeda, H.; Billen, J.H.; Bhatia, T.S.

1998-01-01

The accelerating structure for Spallation Neutron Source (SNS) consists of a radio-frequency-quadrupole-linac (RFQ), a drift-tube-linac (DTL), a coupled-cavity-drift-tube-linac (CCDTL), and a coupled-cavity-linac (CCL). The linac is operated at room temperature. The authors discuss the detailed design of linac which accelerates an H - pulsed beam coming out from RFQ at 2.5 MeV to 1000 MeV. They show a detailed transition from 402.5 MHz DTL with a 4 βλ structure to a CCDTL operated at 805 MHz with a 12 βλ structure. After a discussion of overall feature of the linac, they present an end-to-end particle simulation using the new version of the PARMILA code for a beam starting from the RFQ entrance through the rest of the linac. At 1000 MeV, the beam is transported to a storage ring. The storage ring requires a large (±500-keV) energy spread. This is accomplished by operating the rf-phase in the last section of the linac so the particles are at the unstable fixed point of the separatrix. They present zero-current phase advance, beam size, and beam emittance along the entire linac

An rf modulated electron gun pulser for linacs

International Nuclear Information System (INIS)

Legg, R.; Hartline, R.

1991-01-01

Present linac injector designs often make use of sub-harmonic prebuncher cavities to properly bunch the electron beam before injection into a buncher and subsequent accelerating cavities. This paper proposes an rf modulated thermionic gun which would allow the sub-harmonic buncher to be eliminated from the injector. The performance parameters for the proposed gun are 120 kV operating voltage, macropulse duration-single pulse mode 2 nsec, multiple pulse mode 100 nsec, rf modularing frequency 500 MHz, charge per micropulse 0.4 nC, macropulse repetition frequency 10 Hz (max). The gun pulser uses a grid modulated planar triode to drive the gun cathode. The grid driver takes advantage of recently developed modular CATV rf drivers, high performance solid state pulser devices, and high-frequency fiber optic transmitters for telecommunications. Design details are presented with associated SPICE runs simulating operation of the gun

Linac design for the LCLS project at SLAC

International Nuclear Information System (INIS)

Bharadwaj, V.K.; Bane, K.; Clendenin, J.

1997-05-01

The Linac Coherent Light Source (LCLS) at SLAC is being designed to produce intense, coherent 0.15-nm x-rays. These x-rays will be produced by a single pass of a 15 GeV bunched electron beam through a long undulator. Nominally, the bunches have a charge of 1 nC, normalized transverse emittances of less than 1.5π mm-mr and an rms bunch length of 20 μm. The electron beam will be produced using the last third of the SLAC 3-km linac in a manner compatible with simultaneous operation of the remainder of the linac for PEP-II. The linac design necessary to produce an electron beam with the required brightness for LCLS is discussed, and the specific linac modifications are described

RF linacs for FELs

International Nuclear Information System (INIS)

Schwettman, H.A.

1992-01-01

There are twenty rf linac-driven Free Electron Lasers (FELs) existing or under construction throughout the world and proposals for several more. A number of these FELs have recently been established as facilities to produce coherent optical beams for materials and biomedical research. Both short pulse low duty factor and long pulse high duty factor linac-driven FELs will be discussed. Accelerator issues that influence the performance of an FEL as a scientific instrument will be indicated. (Author) 6 refs., 6 figs., 2 tabs

Permanent quadrupole magnets

International Nuclear Information System (INIS)

Bush, E.D. Jr.

1976-01-01

A family of quadrupole magnets using a soft iron return yoke and circular cross-section permanent magnet poles were fabricated to investigate the feasibility for use in ion or electron beam focusing applications in accelerators and transport lines. Magnetic field measurements yielded promising results. In fixed-field applications, permanent magnets with sufficient gradients would be a low cost substitute for conventional electromagnets, eliminating the need for power supplies, associated wiring, and cooling. Based on preliminary tests, it was seen that permanent quadrupole magnets can offer a low cost, reliable solution in applications requiring small, fixed-field focusing devices for use in ion or electron-beam transport systems. Permanent magnets do require special considerations in design, fabrication, handling, and service that are different than encountered in conventional quadrupole magnets. If these basic conditions are satisfied, the resulting beam-focusing device would be stable, maintenance free, with virtually an indefinite lifetime

BNCT with linac, feasibility study

International Nuclear Information System (INIS)

Alfuraih, A.; Ma, A.; Spyrou, N.M.; Awotwi-Pratt, Joseph

2006-01-01

High energy photon beams from Medical Linear Accelerators (linacs) which are used in radiotherapy produce undesirable neutrons, beside the clinically useful electron and photon beams. Neutrons are produced from the photonuclear reaction (γ,n) of high energy photons with high Z-materials which compose the accelerator head. In this paper the possible use of these undesirable neutrons for BNCT is investigated, making use of high energy linacs already installed in hospitals, primarily for high energy electron and photon therapy and applying them in the context of BNCT. The photoneutron components emitted by the accelerator is the source for Monte Carlo simulations of the interactions that take place within the head of a voxel-based phantom. The neutron flux across the phantom head is calculated using different moderator arrangements and different techniques in the aim of increasing the thermal neutron flux at the targeted site. Also, we shall test different configurations of the linac head to maximize the exposure of high-Z materials to the photon beam, including the removal of the flattening filter, so as to boost the photoneutron production in the linac head. Experimental work will be conducted in hospitals to validate the Monte Carlo simulations. To make use of linacs for BNCT will be advantageous in the sense that the setting in a hospital department is much more acceptable by the public than a reactor installation. This will mean less complications regarding patient positioning and movement with respect to the beams, additional patient transportation and management will be more cost effective. (author)

Energy-Recovery Linacs for Commercial Radioisotope Production

International Nuclear Information System (INIS)

Johnson, Rolland Paul

2016-01-01

Most radioisotopes are produced by nuclear reactors or positive ion accelerators, which are expensive to construct and to operate. Photonuclear reactions using bremsstrahlung photon beams from less-expensive electron linacs can generate isotopes of critical interest, but much of the beam energy in a conventional electron linac is dumped at high energy, making unwanted radioactivation. The largest part of this radioactivation may be completely eliminated by applying energy recovery linac technology to the problem with an additional benefit that the energy cost to produce a given amount of isotope is reduced. Consequently, a Superconducting Radio Frequency (SRF) Energy Recovery Linac (ERL) is a path to a more diverse and reliable domestic supply of short-lived, high-value, high-demand isotopes at a cost lower than that of isotopes produced by reactors or positive-ion accelerators. A Jefferson Lab approach to this problem involves a thin photon production radiator, which allows the electron beam to recirculate through rf cavities so the beam energy can be recovered while the spent electrons are extracted and absorbed at a low enough energy to minimize unwanted radioactivation. The thicker isotope photoproduction target is not in the beam. MuPlus, with Jefferson Lab and Niowave, proposed to extend this ERL technology to the commercial world of radioisotope production. In Phase I we demonstrated that 1) the ERL advantage for producing radioisotopes is at high energies (~100 MeV), 2) the range of acceptable radiator thickness is narrow (too thin and there is no advantage relative to other methods and too thick means energy recovery is too difficult), 3) using optics techniques developed under an earlier STTR for collider low beta designs greatly improves the fraction of beam energy that can be recovered (patent pending), 4) many potentially useful radioisotopes can be made with this ERL technique that have never before been available in significant commercial quantities

Energy-Recovery Linacs for Commercial Radioisotope Production

Energy Technology Data Exchange (ETDEWEB)

Johnson, Rolland Paul [Muplus, Inc., Newport News, VA (United States)

2016-11-19

Most radioisotopes are produced by nuclear reactors or positive ion accelerators, which are expensive to construct and to operate. Photonuclear reactions using bremsstrahlung photon beams from less-expensive electron linacs can generate isotopes of critical interest, but much of the beam energy in a conventional electron linac is dumped at high energy, making unwanted radioactivation. The largest part of this radioactivation may be completely eliminated by applying energy recovery linac technology to the problem with an additional benefit that the energy cost to produce a given amount of isotope is reduced. Consequently, a Superconducting Radio Frequency (SRF) Energy Recovery Linac (ERL) is a path to a more diverse and reliable domestic supply of short-lived, high-value, high-demand isotopes at a cost lower than that of isotopes produced by reactors or positive-ion accelerators. A Jefferson Lab approach to this problem involves a thin photon production radiator, which allows the electron beam to recirculate through rf cavities so the beam energy can be recovered while the spent electrons are extracted and absorbed at a low enough energy to minimize unwanted radioactivation. The thicker isotope photoproduction target is not in the beam. MuPlus, with Jefferson Lab and Niowave, proposed to extend this ERL technology to the commercial world of radioisotope production. In Phase I we demonstrated that 1) the ERL advantage for producing radioisotopes is at high energies (~100 MeV), 2) the range of acceptable radiator thickness is narrow (too thin and there is no advantage relative to other methods and too thick means energy recovery is too difficult), 3) using optics techniques developed under an earlier STTR for collider low beta designs greatly improves the fraction of beam energy that can be recovered (patent pending), 4) many potentially useful radioisotopes can be made with this ERL technique that have never before been available in significant commercial quantities

NPL superconducting Linac control system

International Nuclear Information System (INIS)

Swanson, H.E.; Howe, M.A.; Jackson, L.W.; LaCroix, J.M.; Readdy, H.P.; Storm, D.W.; Van Houten, L.P.

1985-01-01

The control system for the NPL Linac is based on a Microvax II host computer connected in a star network with 9 satellite computers. These satellites use single board varsions of DEC's PDP 11 processor. The operator's console uses high performance graphics and touch screen technology to display the current linac status and as the means for interactively controlling the operation of the accelerator

First beam in Linac4 DTL

CERN Multimedia

Katarina Anthony

2014-01-01

Following the installation of the Linac4 Drift Tube Linac (DTL) earlier this summer (see here), the first DTL tank saw beams at 12 MeV on 5 August.   Transverse emittance measured at 12 MeV after the DTL tank1 using a temporary slit-and-grid emittance device. You never forget your first beam. That was especially true for the Linac4 DTL team, as it followed years of design, construction and vigorous testing. "We performed countless measurements of the geometry, vacuum and magnet polarisation of the DTL tanks while we were in the workshop," says Suitbert Ramberger, project engineer for the Linac4 DTL. "Add that preparation to the excellent RF conditioning that we carried out in the weeks before the beam tests and I was confident that the acceleration with beam would fully meet expectations!" Indeed it did. Beam commissioning tests ran until 21 August and found the DTL operating with nominal transmission. This successful run has confirmed the innovative design ...

Diagnostic expert system in the PF LINAC

International Nuclear Information System (INIS)

Abe, Isamu; Nakahara, Kazuo; Kitamura, Masaharu.

1992-01-01

A prototype diagnostic expert system (ES) was developed for the Photon Factory 2.5-GeV electron/positron LINAC injector system. The ES has been on-lined with the conventional linac computer network for receiving real data. This project was undertaken in an attempt to reduce the linac operator's mental workload, diagnosis duties, and to explore Artificial Intelligence (AI) technologies. The outlook for ES and its problems, and what has been achieved are outlined in this presentation. (author)

Measurements of longitudinal phase space in the SLC linac

International Nuclear Information System (INIS)

Bane, K.; Adolphsen, C.; Lavine, T.L.; Ross, M.; Seeman, J.; Thompson, K.

1990-05-01

In the Stanford Linear Collider the beam leaves a damping ring and then enters the Ring-to-Linac (RTL) transfer line. In the RTL it is compressed in length by a factor of 10 by means of an rf section, with which a longitudinally correlated energy variation is induced in the beam, and a following beam line which has non-zero momentum compaction. The compressed beam then enters the linac proper. In this paper we describe three measurements of longitudinal properties of the beam in the SLC linac. We present measurements of single bunch beam loading, of the energy spectrum at the end of the linac, and of the linac bunch length. Since the results of all three measurements depend on the beam's longitudinal charge distribution in the linac they, in turn, also depend on the bunch lengthening that occurs in the damping rings, as well as on the behavior of the compressor. The results of the first two measurements, in addition, depend critically on the strength of the longitudinal wakefields in the linac. The results of these three measurements are compared with simulations. For these calculations, at any given current, the potential well distortion in the damping ring is first computed. The compression process is then simulated to obtain the longitudinal charge distribution in the linac. For the first two measurements this distribution is then convolved with the calculated longitudinal wake function of the SLAC linac in order to obtain the induced voltage. Finally, the induced voltage is combined with the effect of the linac rf wave to give the final energy spectrum. 8 refs., 5 figs

The pros and cons of cryogenic accelerators: An engineering point of view

International Nuclear Information System (INIS)

Fox, W.

1991-01-01

The design of cryogenic linacs is a challenging engineering task; however, significant improvements in accelerator performance are possible. Resistive power losses may be reduced by a factor of four or greater. Greater flexibility is possible in thermal management as a result of substantial increases in thermal conductivity for certain materials. Radio frequency structures may by an order of magnitude more stable in terms of frequency shifts due to thermal transients resulting form very small coefficients of thermal expansion at cryogenic temperatures. Significant engineering problems must be addressed, such as the design of effective rf contacts that will not be affected by thermal cycling and the design of cryogenic mechanisms and dynamic components, such as frequency tuners, that operate reliably at cryogenic operating temperatures. The areas of high-power sparking and multipactoring have not yet been experimentally addressed. Both Los Alamos, Grumman Aerospace Corporation, and Boeing Corporation have built or are building and testing cryogenic accelerator structures. This paper reviews the advances made in cryogenic technology applied to radio frequency quadrupole (RFQ) and drift tube linac (DTL) structures and will discuss the advantages and engineering challenges that these linacs present

Oxygen ion source and RFQ for Linac 1

CERN Multimedia

Photographic Service

1986-01-01

As injector to the PS Booster, Linac 1 was replaced by Linac 2 in 1980. It continued to be used for the acceleration of oxygen and sulfur ions. In 1984, its Cockcroft-Walton preinjector was replaced by an RFQ. In the foreground at the right is the oxygen ion source. A 90 deg bending magnet selects O6+ ions which are preaccelerated in an RFQ and enter Linac 1, at the far left. In the background is the proton and negative hydrogen ion source, followed by the 520 keV RFQ-1 and a bending magnet towards the entrance of Linac 1.

Commissioning results of the HZB quadrupole resonator

CERN Document Server

Kleindienst, Raphael; Knobloch, Jens; Kugeler, Oliver

2015-01-01

Recent cavity results with niobium have demonstrated the necessity of a good understanding of both the BCS and residual resistance. For a complete picture and comparison with theory, it is essential that one can measure the RF properties as a function of field, temperature, frequency and ambient magnetic field. Standard cavity measurements are limited in their ability to change all parameters freely and in a controlled manner. On the other hand, most sample measurement setups operate at fairly high frequency, where the surface resistance is always BCS dominated. The quadrupole resonator, originally developed at CERN, is ideally suited for characterization of samples at typical cavity RF frequencies. We report on a modified version of the QPR with improved RF figures of merit for high-field operation. Experimental challenges in the commissioning run and alternate designs for simpler sample changes are shown alongside measurement results of a large grain niobium sample.

ASACUSA's radio-frequency quadrupole decelerator, open to show the four-rod structure along the centre, which crosses 35 resonator chambers formed by the vertical partitions.

CERN Multimedia

Laurent Guiraud

2000-01-01

The Radio-Frequency Quadrupole, RFQD, which further decelerates antiprotons ejected from the Antiproton Decelerator (AD). Starting from a momentum of 100 MeV/c (kinetic energy 5.3 MeV), the RFQD delivers very-low-energy antiprotons, adjustable between 10 and 110 keV, to the experiment ASACUSA. In picture _02, the view from the upstream end shows its 4-rod structure, traversing 35 resonator chambers formed by the vertical partitions. The tank has an inner diameter of 390 mm and is pumped to a vacuum of a few E-8 Torr.

Study on design of proton linacs

International Nuclear Information System (INIS)

Yu Qingchang

2000-01-01

Two important directions in the development of proton linacs are high-current proton linacs (mainly applied in nuclear power field) and compact proton linacs (for proton therapy). There are some common characteristics in them: (1) Employment of the novel accelerating structures, which are combination and evolution of the conventional ones; (2) Accelerating beam with small emittance; (3) Requirement for high reliability. The construction of the former is, however, much more difficult because it still needs low beam lose rate and as high power transformation efficiency as possible. Some important problems in the design of these accelerators are discussed and some schemes designed are presented

Upgrade of the AGS H- linac

International Nuclear Information System (INIS)

Alessi, J.G.; Buxton, W.; Kponou, A.; LoDestro, V.; Mapes, M.; McNerney, A.J.; Raparia, D.

1994-01-01

The AGS linac presently accelerates 25 mA of H - to 200 MeV at a 5 Hz rep-rate and 500 μs pulse width. The Booster takes 4 pulses every 3.8 seconds, and the remaining pulses are used for isotope production. The authors are in the process of upgrading the linac to increase the average current delivered for isotope production by more than a factor of two, while at the same time expecting to decrease linac downtime. Various aspects of this upgrade are discussed, including the upgrade of the control system, new high power transmission line, transport line vacuum, and rf power supply system upgrades

The upgraded Munich linear heavy ion postaccelerator

International Nuclear Information System (INIS)

Ratzinger, U.; Nolte, E.; Geier, R.; Gartner, N.; Morinaga, H.

1987-01-01

The Munich heavy ion postaccelerator was extended, consisting of two cavities with an interdigital H-type structure now. The frequency is doubled in the second section. A special kind of beam dynamics for O 0 -synchronous particle structures was developed, which results in good particle transmission though only one compact quadrupole-doublet is installed over the length of both linacs. Beamtime experience confirms the transport calculations

A linac for the Spallation Neutron Source

International Nuclear Information System (INIS)

Jason, A.J.

1998-01-01

The Spallation Neutron Source Project (SNS), to be constructed at Oak Ridge National Laboratory, accelerates H - ions to an energy of 1.0 GeV with an average current of 1-mA for injection into an accumulator ring that produces the short intense burst of protons needed for the spallation-neutron source. The linac will be the most intense source of H - ions and as such requires advanced design techniques to meet project technical goals. In particular, low beam loss is stressed for the chopped beam placing strong requirements on the beam dynamics and linac construction. Additionally, the linac is to be upgraded to the 2- and 4-MW beam-power levels with no increase in duty factor. The author gives an overview of the linac design parameters and design choices made

Source-to-accelerator quadrupole matching section for a compact linear accelerator

Science.gov (United States)

Seidl, P. A.; Persaud, A.; Ghiorso, W.; Ji, Q.; Waldron, W. L.; Lal, A.; Vinayakumar, K. B.; Schenkel, T.

2018-05-01

Recently, we presented a new approach for a compact radio-frequency (RF) accelerator structure and demonstrated the functionality of the individual components: acceleration units and focusing elements. In this paper, we combine these units to form a working accelerator structure: a matching section between the ion source extraction grids and the RF-acceleration unit and electrostatic focusing quadrupoles between successive acceleration units. The matching section consists of six electrostatic quadrupoles (ESQs) fabricated using 3D-printing techniques. The matching section enables us to capture more beam current and to match the beam envelope to conditions for stable transport in an acceleration lattice. We present data from an integrated accelerator consisting of the source, matching section, and an ESQ doublet sandwiched between two RF-acceleration units.

Electron Signal Detection for the Beam-Finder Wire of the Linac Coherent Light Source Undulator

International Nuclear Information System (INIS)

Wu, Juhao; Emma, P.; Field, R.C.; SLAC

2006-01-01

The Linac Coherent Light Source (LCLS) is a SASE x-ray Free-Electron Laser (FEL) based on the final kilometer of the Stanford Linear Accelerator. The tight tolerances for positioning the electron beam close to the undulator axis calls for the introduction of Beam Finder Wire (BFW) device. A BFW device close to the upstream end of the undulator segment and a quadrupole close to the down stream end of the undulator segment will allow a beam-based undulator segment alignment. Based on the scattering of the electrons on the BFW, we can detect the electron signal in the main dump bends after the undulator to find the beam position. We propose to use a threshold Cherenkov counter for this purpose. According to the signal strength at such a Cherenkov counter, we then suggest choice of material and size for such a BFW device in the undulator

Torques on quadrupoles

OpenAIRE

Torres del Castillo, G.F; Méndez Garrido, A

2006-01-01

Making use of the fact that a 2l-pole can be represented by means of l vectors of the same magnitude, the torque on a quadrupole in an inhomogeneous external field is expressed in terms of the vectors that represent the quadrupole and the gradient of the external field. The conditions for rotational equilibrium are also expressed in terms of these vectors. Haciendo uso de que un multipolo de orden 2l puede representarse mediante l vectores de la misma magnitud, la torca sobre un cuadripolo...

400 MeV upgrade for the Fermilab linac

International Nuclear Information System (INIS)

MacLachlan, J.A.

1989-01-01

Fermilab has plans for a comprehensive accelerator upgrade to open new possibilities for both the fixed target and collider experimental programs. An early step in this program is to increase the energy of the linac from 200 to 400 MeV by replacing the last four of its nine 201 MHz Alvarez tanks with twenty-eight 805 MHz side-coupled cavity chains operating at about 8 MV/m average axial field. The principal purpose is to reduce the incoherent spacecharge tuneshift at injection into the Booster which currently limits both the brightness of the beam, an important determinant of collider luminosity, and total intensity to produce both the antiprotons for the collider and the beams to fixed target experimental areas. Other consequences of higher Booster injection energy expected to contribute to some degree of higher intensity limits and improved operational characteristics include improved quality of the guide field at injection, reduced frequency swing for the rf systems, and smaller emittance for the injected beam. The linac upgrade project has moved from a 1986 study through a development project including structure models and numerical studies to a full-feature module prototyping starting this year

Post-acceleration of laser driven protons with a compact high field linac

Science.gov (United States)

Sinigardi, Stefano; Londrillo, Pasquale; Rossi, Francesco; Turchetti, Giorgio; Bolton, Paul R.

2013-05-01

We present a start-to-end 3D numerical simulation of a hybrid scheme for the acceleration of protons. The scheme is based on a first stage laser acceleration, followed by a transport line with a solenoid or a multiplet of quadrupoles, and then a post-acceleration section in a compact linac. Our simulations show that from a laser accelerated proton bunch with energy selection at ~ 30MeV, it is possible to obtain a high quality monochromatic beam of 60MeV with intensity at the threshold of interest for medical use. In the present day experiments using solid targets, the TNSA mechanism describes accelerated bunches with an exponential energy spectrum up to a cut-off value typically below ~ 60MeV and wide angular distribution. At the cut-off energy, the number of protons to be collimated and post-accelerated in a hybrid scheme are still too low. We investigate laser-plasma acceleration to improve the quality and number of the injected protons at ~ 30MeV in order to assure efficient post-acceleration in the hybrid scheme. The results are obtained with 3D PIC simulations using a code where optical acceleration with over-dense targets, transport and post-acceleration in a linac can all be investigated in an integrated framework. The high intensity experiments at Nara are taken as a reference benchmarks for our virtual laboratory. If experimentally confirmed, a hybrid scheme could be the core of a medium sized infrastructure for medical research, capable of producing protons for therapy and x-rays for diagnosis, which complements the development of all optical systems.

A SUPER-CONDUCTING LINAC DRIVER FOR THE HFBR.

Energy Technology Data Exchange (ETDEWEB)

Alessi, J.; Raparia, D.; Ruggiero, A.G.

2000-08-21

This paper reports on the feasibility study of a proton Super-Conducting Linac (SCL) as a driver for the High-Flux Breeder Reactor (HFBR) at Brookhaven National Laboratory (BNL). The Linac operates in Continuous Wave (CW) mode to produce an average 10 MW of beam power. The Linac beam energy is 1.0 GeV. The average proton beam intensity in exit is 10 mA.

Muon Acceleration Concepts for NuMAX: "Dual-use" Linac and "Dogbone" RLA

Science.gov (United States)

Bogacz, S. A.

2018-02-01

We summarize the current state of a concept for muon acceleration aimed at a future Neutrino Factory. The main thrust of these studies was to reduce the overall cost while maintaining performance by exploring the interplay between the complexity of the cooling systems and the acceptance of the accelerator complex. To ensure adequate survival for the short-lived muons, acceleration must occur at high average gradient. The need for large transverse and longitudinal acceptances drives the design of the acceleration system to an initially low RF frequency, e.g., 325 MHz, which is then increased to 650 MHz as the transverse size shrinks with increasing energy. High-gradient normal conducting RF cavities at these frequencies require extremely high peak-power RF sources. Hence superconducting RF (SRF) cavities are chosen. We consider two cost effective schemes for accelerating muon beams for a stageable Neutrino Factory: exploration of the so-called "dual-use" linac concept, where the same linac structure is used for acceleration of both H- and muons and, alternatively, an SRF-efficient design based on a multi-pass (4.5) "dogbone" RLA, extendable to multi-pass FFAG-like arcs.

SLAC Linac Preparations for FACET

International Nuclear Information System (INIS)

Erickson, Roger

2011-01-01

The SLAC 3km linear electron accelerator has been cut at the two-thirds point to provide beams to two independent programs. The last third provides the electron beam for the Linac Coherent Light Source (LCLS), leaving the first two-thirds available for FACET, the new experimental facility for accelerator science and test beams. In this paper, we describe this separation and projects to prepare the linac for the FACET experimental program.

Radioisotope production linac

International Nuclear Information System (INIS)

Stovall, J.E.; Hansborough, L.D.; O'Brien, H.A.

1981-01-01

A 70-MeV proton beam would open a new family of medical radioisotopes (including the important 123 I) to wide application. A 70-MeV, 500-μA linac is described, based on recent innovations in accelerator technology. It would be 27.3 m long, cost approx. $6 million, and the cost of power deposited in the radioisotope-production target is comparable to existing cyclotrons. By operating the rf-power system to its full capability, the same accelerator is capable of producing a 1140-μA beam, and the cost per beam watt on the target is less than half that of comparable cyclotrons. The technology to build such a linac is in a mature stage of developmnt, ready for use by industry

Numerical studies and measurements on the side-coupled drift tube linac (SCDTL) accelerating structure

International Nuclear Information System (INIS)

Picardi, L.; Ronsivalle, C.; Spataro, B.

2000-01-01

The 3 GHz linac section designed for the low energy (7-65 MeV) part of TOP (therapy oncological protons) linac (Picardi et al., 1997, 1996), operating at 3 GHz frequency and in π/2 mode, consists of eight modules of the structure SCDTL (side-coupled drift tube linac). The first module is designed to accelerate 7 MeV protons up to 13.4 MeV, and a prototype is presently under construction. Electromagnetic field calculations of the non-axisymmetric cavities carried out by using MAFIA 3D code (Weiland, 1986) gave the RF wall losses and the full mode spectrum. Two prototypes, an aluminium model of the first quintuplet and a copper model of the last triplet of the module, were built in order to check the complex 3D properties of the structure, and to refine the tuning procedure. This paper reports the results of the 3D numerical simulations about the RF properties of the first module and of some RF measurements on the prototypes. The beam dynamics study results in the SCDTL section are discussed as well

Updating the CSNS injector linac to 250 MeV with superconducting double-spoke cavities

International Nuclear Information System (INIS)

Li Zhihui; Fu Shinian

2015-01-01

In order to update the beam power from 100 kW to 500 kW in the China Spallation neutron source (CSNS) Phase Ⅱ, one of the important measures is to replace the 80 m long beam transport line between the present 80 MeV linac injector and the rapid cycling synchrotron (RCS) to another kind of acceleration structure. In this paper, we proposed a scheme based on 324 MHz double-spoke superconducting cavities. Unlike the superconducting elliptical cavity and normal conducting coupled cavity linac (CCL) structure, the double-spoke cavity belongs to the TE mode structure and has a smaller transverse dimension compared with that of the TH mode one. It can work at base frequency as the drift tube Linac (DTL) section, so that the cost and complexity of the RF system will be much decreased, and the behaviors of the beam dynamics are also improved significantly because of the low charge density and larger longitudinal acceptance. Furthermore, because of the relatively longer interactive length between the charged particle and the electromagnetic field per cell, it needs relatively less cell numbers and it has larger velocity acceptance compared with the double frequency TH structures. The superconducting section consists of 14 periods, each of which includes 3 superconducting cavities encapsulated in one cryomodule and a doublet in room temperate. The general considerations on cavity and beam dynamics design are discussed and the main results are presented. (authors)

SU-E-T-468: Implementation of the TG-142 QA Process for Seven Linacs with Enhanced Beam Conformance

Energy Technology Data Exchange (ETDEWEB)

Woollard, J; Ayan, A; DiCostanzo, D; Grzetic, S; Hessler, J; Gupta, N [OH State University, Columbus, OH (United States)

2015-06-15

Purpose: To develop a TG-142 compliant QA process for 7 Varian TrueBeam linear accelerators (linacs) with enhanced beam conformance and dosimetrically matched beam models. To ensure consistent performance of all 7 linacs, the QA process should include a common set of baseline values for use in routine QA on all linacs. Methods: The TG 142 report provides recommended tests, tolerances and frequencies for quality assurance of medical accelerators. Based on the guidance provided in the report, measurement tests were developed to evaluate each of the applicable parameters listed for daily, monthly and annual QA. These tests were then performed on each of our 7 new linacs as they came on line at our institution. Results: The tolerance values specified in TG-142 for each QA test are either absolute tolerances (i.e. ±2mm) or require a comparison to a baseline value. The results of our QA tests were first used to ensure that all 7 linacs were operating within the suggested tolerance values provided in TG −142 for those tests with absolute tolerances and that the performance of the linacs was adequately matched. The QA test results were then used to develop a set of common baseline values for those QA tests that require comparison to a baseline value at routine monthly and annual QA. The procedures and baseline values were incorporated into a spreadsheets for use in monthly and annual QA. Conclusion: We have developed a set of procedures for daily, monthly and annual QA of our linacs that are consistent with the TG-142 report. A common set of baseline values was developed for routine QA tests. The use of this common set of baseline values for comparison at monthly and annual QA will ensure consistent performance of all 7 linacs.

SU-E-T-468: Implementation of the TG-142 QA Process for Seven Linacs with Enhanced Beam Conformance

International Nuclear Information System (INIS)

Woollard, J; Ayan, A; DiCostanzo, D; Grzetic, S; Hessler, J; Gupta, N

2015-01-01

Purpose: To develop a TG-142 compliant QA process for 7 Varian TrueBeam linear accelerators (linacs) with enhanced beam conformance and dosimetrically matched beam models. To ensure consistent performance of all 7 linacs, the QA process should include a common set of baseline values for use in routine QA on all linacs. Methods: The TG 142 report provides recommended tests, tolerances and frequencies for quality assurance of medical accelerators. Based on the guidance provided in the report, measurement tests were developed to evaluate each of the applicable parameters listed for daily, monthly and annual QA. These tests were then performed on each of our 7 new linacs as they came on line at our institution. Results: The tolerance values specified in TG-142 for each QA test are either absolute tolerances (i.e. ±2mm) or require a comparison to a baseline value. The results of our QA tests were first used to ensure that all 7 linacs were operating within the suggested tolerance values provided in TG −142 for those tests with absolute tolerances and that the performance of the linacs was adequately matched. The QA test results were then used to develop a set of common baseline values for those QA tests that require comparison to a baseline value at routine monthly and annual QA. The procedures and baseline values were incorporated into a spreadsheets for use in monthly and annual QA. Conclusion: We have developed a set of procedures for daily, monthly and annual QA of our linacs that are consistent with the TG-142 report. A common set of baseline values was developed for routine QA tests. The use of this common set of baseline values for comparison at monthly and annual QA will ensure consistent performance of all 7 linacs

Operational experience with the CERN hadron linacs

International Nuclear Information System (INIS)

Charmot, H.; Dutriat, C.; Hill, C.E.; Langbein, K.; Lombardi, A.M.; O'Neil, M.; Tanke, E.; Vretenar, M.

1996-01-01

The present CERN proton linac (Linac2) was commissioned in 1978 and since that date has been the primary source of protons to the CERN accelerator complex. During the past 18 years, the machine has had a very good reliability record in spite of the demands made upon it. Modifications have been made with the view of maintaining this reliability with reduced resources and new requirements from the users. Further demands will be made in the future for LHC operation. In 1994, a new linac for heavy ion production was put into service replacing the original CERN proton linac. As this machine was built within an international collaboration, operation had to take into account the novelty of the techniques used and the variety of equipment supplied by outside collaborators. Even so, the new machine has also had very good reliability. (author)

Superconducting LINAC booster for the Mumbai pelletron

Indian Academy of Sciences (India)

LINAC), to boost the energy of heavy ion beams from the 14UD Pelletron accelerator, at Tata Institute of Fundamental Research, Mumbai. The accelerating structures in the LINAC are quarter wave resonators (QWR) coated with lead which is ...

Resonant excitation of high order modes in the 3.9 GHz cavity of the Linac Coherent Light Source

Science.gov (United States)

Lunin, A.; Khabiboulline, T.; Solyak, N.; Sukhanov, A.; Yakovlev, V.

2018-02-01

Construction of the Linac Coherent Light Source II (LCLS-II) is underway for the world's first hard x-ray free-electron laser. A central part of the LCLS-II project is a 4 GeV superconducting radio frequency electron linac that will operate in the continuous wave (cw) mode. The linac is segmented into four sections named as L 0 , L 1 , L 2 , and L 3 . Two 3.9 GHz cryomodules, each housing of eight third-harmonic cavities similar to the cavities developed for the European X-ray Free Electron Laser (XFEL), will be used in section L 1 of the linac for linearizing the longitudinal beam profile. In this paper, we present a study of trapped high order modes (HOMs) excited by a cw electron beam in the third-harmonic cavities of the LCLS-II linac. A detailed comparison of the original XFEL design and the LCLS-II design with a modified end group is performed in order to estimate the effect of a reduced beam pipe aperture on the efficiency of HOM damping. Furthermore, we apply a statistical analysis of the eigenmode spectrum for the estimation of the probability of resonant HOM losses and influence of HOMs on beam dynamics.

Quadrupole moments of hadrons

International Nuclear Information System (INIS)

Krivoruchenko, M.I.

1985-01-01

In chiral bag model an expression is obtained for the quark wave functions with account of color and pion interaction of quarks. The quadrupole moments of nonstrange hadrons are calculated. Quadrupole moment of nucleon isobar is found to be Q(Δ)=-6.3x10 -28 esub(Δ)(cm)sup(2). Fredictions of the chiral bag model are in strong disagreement with the non-relativistic quark model

The Pre-Injector Linac for the Diamond Light Source

CERN Document Server

Christou, C

2004-01-01

The Diamond Light Source is a new medium-energy high brightness synchrotron light facility which is under construction on the Rutherford Appleton Laboratory site in the U.K. The accelerator facility can be divided into three major components; a 3 GeV 561 m circumference storage ring, a full-energy booster synchrotron and a 100 MeV pre-injector linac. This paper describes the linac design and plans for operation. The linac is supplied by ACCEL Instruments GmbH under a turn-key contract, with Diamond Light Source Ltd. providing linac beam diagnostics, control system hardware and standard vacuum components. Commissioning of the linac will take place in early 2005 and user operation of the facility will commence in 2007.

Photon and photoneutron spectra produced in radiotherapy Linacs

International Nuclear Information System (INIS)

Vega C, H. R.; Martinez O, S. A.; Benites R, J. L.; Lallena, A. M.

2011-10-01

A Monte Carlo calculation, using the MCNPX code, was carried out in order to estimate the photon and neutron spectra in two locations of two linacs operating at 15 and 18 MV. Detailed models of both linac heads were used in the calculations. Spectra were estimated below the flattening filter and at the isocenter. Neutron spectra show two components due to evaporation and knock-on neutrons. Lethargy spectra under the filter were compared to the spectra calculated from the function quoted by Tosi et al. that describes reasonably well neutron spectra beyond 1 MeV, though tends to underestimate the energy region between 10 -6 and 1 MeV. Neutron and Bremsstrahlung spectra show the same features regardless of the linac voltage. The amount of photons and neutrons produced by the 15 MV linac is smaller than that found for the 18 MV linac. As expected, Bremsstrahlung spectra ends according to the voltage used to accelerate the electrons. (Author)

Photon and photoneutron spectra produced in radiotherapy Linacs

Energy Technology Data Exchange (ETDEWEB)

Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Calle Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico); Martinez O, S. A. [Universidad Pedagogica y Tecnologica de Colombia, Grupo de Fisica Nuclear Aplicada y Simulacion, Av. Central del Norte Km. 1, Via Paipa Tunja, Boyaca (Colombia); Benites R, J. L. [Universidad Autonoma de Nayarit, Postgrado CBAP, Carretera Tepic Compostela Km. 9, Xalisco, Nayarit (Mexico); Lallena, A. M., E-mail: fermineutron@yahoo.com [Universida de Granada, Departamento de Fisica Atomica, Molecular y Nuclear, E-18071 Granada (Spain)

2011-10-15

A Monte Carlo calculation, using the MCNPX code, was carried out in order to estimate the photon and neutron spectra in two locations of two linacs operating at 15 and 18 MV. Detailed models of both linac heads were used in the calculations. Spectra were estimated below the flattening filter and at the isocenter. Neutron spectra show two components due to evaporation and knock-on neutrons. Lethargy spectra under the filter were compared to the spectra calculated from the function quoted by Tosi et al. that describes reasonably well neutron spectra beyond 1 MeV, though tends to underestimate the energy region between 10{sup -6} and 1 MeV. Neutron and Bremsstrahlung spectra show the same features regardless of the linac voltage. The amount of photons and neutrons produced by the 15 MV linac is smaller than that found for the 18 MV linac. As expected, Bremsstrahlung spectra ends according to the voltage used to accelerate the electrons. (Author)

1-GeV Linac Upgrade Study at Fermilab

International Nuclear Information System (INIS)

Popovic, M.; Moretti, A.; Noble, R.; Schmidt, C.W.

1998-09-01

A linac injector for a new proton source complex at Fermilab is assumed to have a kinetic energy of 1 GeV. This linac would be sized to accelerate 100 mA of H - beam in a 200 microsecond pulse at a 15 Hz repetition rate. This would be adequate to produce ∼10 14 protons per pulse allowing for future improvements of the new proton source complex. An alternate proposal is to add 600 MeV of side coupled cavity linac at 805 MHz to the existing 400 MeV Linac. This addition may either be in a new location or use the present Booster tunnel. A discussion of these possibilities will be given

Florida State University superconducting linac

International Nuclear Information System (INIS)

Myers, E.G.; Fox, J.D.; Frawley, A.D.; Allen, P.; Faragasso, J.; Smith, D.; Wright, L.

1988-01-01

As early as the fall of 1977 it was decided that the future research needs of their nuclear structure laboratory required an increase in energy capability to at least 8 MeV per nucleon for the lighter ions, and that these needs could be met by the installation of a 17 MV tandem Van de Graaff accelerator. The chief problem with this proposal was the high cost. It became apparent that a far less expensive option was to construct a linear accelerator to boost the energy from their existing 9 MV tandem. The options open to them among linac boosters were well represented by the room temperature linac at Heidelberg and the superconducting Stony Brook and Argonne systems. By the Spring of 1979 it had been decided that both capital cost and electric power requirements favored a superconducting system. As regards the two superconducting resonator technologies - the Argonne niobium-copper or the Caltech-Stony Brook lead plated copper - the Argonne resonators, though more expensive to construct, had the advantages of more boost per resonator, greater durability of the superconducting surface and less stringent beam bunching requirements. In 1980 pilot funding from the State of Florida enabled the construction of a building addition to house the linac and a new target area, and the setting up of a small, three resonator, test booster. Major funding by the NSF for the laboratory upgrade started in 1984. With these funds they purchased their present helium liquefaction and transfer system and constructed three large cryostats, each housing four Argonne beta = 0.105 resonators and two superconducting solenoids. The last large cryostat was completed and installed on-line early this year and the linac was dedicated on March 20. Nuclear physics experiments using the whole linac began in early June. 4 references, 6 figures, 1 table

Measurement of the quadrupole moments of the strongly deformed nuclei 18173Ta108 and 18375Re108 by hyperfine interaction in metals

International Nuclear Information System (INIS)

Netz, G.

1974-01-01

The quadrupole moments of two single particle proton states were measured in the strongly deformed nuclei region. Both measurements are independent of model because the field gradient is known in a rhenium lattice as well as at the nucleus site of a rhenium atom and also at the nucleus site of an incorporated tantalum atom. The quadrupole moments could thus be directly extracted from the quadrupole interaction frequency, the product of quadrupole moment and field gradient. For the 482 keV state (I = 5/2 + ) in 181 73 Ta 108 one obtains a quadrupole moment of: Q (5/2) = 2.5 +- 0.2 barn. For the 496 keV state (I = 9/2 - ) in 183 75 Re 108 , a quadrupole moment of: Q (0/2) = 3.6 +- 0.4 barn is found. This value agrees well with other experimental data within the framework of the collective model. (orig./LH) [de

The optimized advanced demonstrator for the SC CW heavy ion linac at GSI

Energy Technology Data Exchange (ETDEWEB)

Schwarz, Malte; Basten, Markus; Busch, Marco; Dziuba, Florian; Podlech, Holger; Ratzinger, Ulrich; Tiede, Rudolf [Institut fuer Angewandte Physik, Goethe-Universitaet Frankfurt am Main (Germany); Gettmann, Viktor; Heilmann, Manuel [GSI Helmholtzzentrum, Darmstadt (Germany); Barth, Winfried; Mickat, Sascha [GSI Helmholtzzentrum, Darmstadt (Germany); HIM, Helmholtzinstitut, Mainz (Germany); Miski-Oglu, Maksym [HIM, Helmholtzinstitut, Mainz (Germany); Aulenbacher, Kurt [KPH, Johannes Gutenberg Universitaet, Mainz (Germany)

2016-07-01

For future experiments with heavy ions at the coulomb barrier within the SHE research project a multi-stage R and D program of GSI, HIM and IAP is currently under progress. It aims at developing a superconducting (sc) continuous wave (cw) LINAC with multiple CH-cavities as key components. As intermediate step towards the whole LINAC, the Optimized Advanced Demonstrator is proposed. Consisting of short CH-cavities and cryostats, it could provide several advantages regarding velocity acceptance, higher tolerance with respect to frequency and field deviation, easier mounting, handling and maintenance as well as a more robust longitudinal beam dynamic. The beam dynamics concept is based on EQUUS (Equidistant Multigap Structure) constant-beta cavities. The corresponding simulations for the proposed next extension stage - the Optimized Advanced Demonstrator - will be presented.

Study of characteristics of linac with TWRR

International Nuclear Information System (INIS)

Wang, Y.L.; Toyama, S.; Emoto, T.; Nomura, M.; Takahashi, N.; Oshita, H.; Hirano, K.; Sato, I.

1994-01-01

High power electron linac which is developed by PNC is an electron linac with the TWRR (Traveling Wave Resonant Ring). Some phenomena occurred on our high power test are mentioned. Some important characteristics such as stability and phase characteristic are discussed. (author)

A compact ESQ system for transport and focusing of H- beam from ion source to RFQ

International Nuclear Information System (INIS)

Guharay, S.K.; Allen, C.K.; Reiser, M.; Saadatmand, K.; Chang, C.R.

1992-01-01

A compact, 6-lens electrostatic quadrupole (ESQ) LEBT (low energy beam transport) system has been constructed at the University of Maryland to transport a 30 mA, 35 kV H - beam over a distance of about 30 cm. A short einzel lens section is included at the end of the ESQ LEBT to establish a good matching of the beam to the radio frequency quadrupole (RFQ) accelerator, and to meet the emittance requirements of the linac in the Super-conducting Super Collider. Computer code predictions on the beam dynamics through the LEBT with experimentally measured input beam data are discussed. (Author) 5 figs., 6 refs

Physics design of an accelerator for an accelerator-driven subcritical system

Directory of Open Access Journals (Sweden)

Zhihui Li

2013-08-01

Full Text Available An accelerator-driven subcritical system (ADS program was launched in China in 2011, which aims to design and build an ADS demonstration facility with the capability of more than 1000 MW thermal power in multiple phases lasting about 20 years. The driver linac is defined to be 1.5 GeV in energy, 10 mA in current and in cw operation mode. To meet the extremely high reliability and availability, the linac is designed with much installed margin and fault tolerance, including hot-spare injectors and local compensation method for key element failures. The accelerator complex consists of two parallel 10-MeV injectors, a joint medium-energy beam transport line, a main linac, and a high-energy beam transport line. The superconducting acceleration structures are employed except for the radio frequency quadrupole accelerators (RFQs which are at room temperature. The general design considerations and the beam dynamics design of the driver linac complex are presented here.

Quadrupole to BPM offset determination in Indus-2

International Nuclear Information System (INIS)

Jena, Saroj; Ghodke, A.D.; Singh, G.

2009-01-01

A feasibility of finding the quadrupole to BPM offset using beam based alignment (BBA) technique in Indus-2 has been studied. The measurements of the offsets between BPM and quadrupoles could be performed by using quadratic fitting for the minima of the orbit response w. r. t. changes in the quadrupole strengths. These offsets will be integrated to the orbit data during closed orbit correction. There are 72 quadrupoles and 56 BPMs in Indus-2. However the assessment of Quad-BPM offsets is not feasible in some cases due to non-availability of BPM adjacent to quadrupole and also in some cases because of a large phase advance between quadrupole and nearby BPM. Here single corrector method is used to obtain these offsets and assumed the current of each quadrupole can be varied independently. A graphical user interface (GUI) is developed in MATLAB for the use of BBA in Indus-2. (author)

The superconducting linac booster at the ANU

International Nuclear Information System (INIS)

Weisser, D.C.

1995-02-01

This report outlines the progress of the installation of the superconducting Linac booster at the Australian National University. The Linac is based upon four modules, three of which contain three split-loop resonators. The fourth cryostat was intended to be a superbuncher and so houses only one resonator. The first stage of Linac operation will employ only three modules with 2 MV/m from each resonator. It is expected that the implementation of all nine modules, in subsequent stages, would boost beams by 18 MV/q. The project has fostered productive international collaboration between UK and Australian scientists. 1 tab., 6 figs

Overview of the Pelletron Linac facility, Mumbai

International Nuclear Information System (INIS)

Pillay, R.G.

2011-01-01

The Pelletron LINAC Facility at TIFR, Mumbai, comprising the 14 MV Pelletron and the superconducting LINAC booster caters to a variety of experiments in basic and applied Sciences. The Liquid Helium Refrigeration plant for the LINAC has been upgraded to enhance the refrigeration capacity. New instrumentation and interface for control and monitor of the cryogenic parameters, beam diagnostics and beam transport devices have been developed and installed. Digital implementation of the LLRF control has been demonstrated. All seven beam lines in new user halls have been commissioned and several new experimental setups have been added. (author)

Bead perturbation measurement for the KEK linac cavity

International Nuclear Information System (INIS)

Okumura, Shoji; Swenson, D.A.

1975-03-01

The axial electric field in the KEK linac cavity is measured by a bead perturbation method. The beat signal of around 1 kHz is generated with the rf signals from the cavity in self-excitation and from a signal generator whose output frequency is fixed. The period of the beat signal is measured by a counter in order to detect the small change in the resonant frequency of the cavity due to a bead perturbation. The counting data are transferred to a mini-computer after each period of the beat signal. The average fields of each gap are calculated in the computer and they are displayed on a storage oscilloscope. It takes about 50 seconds to complete the whole process of the measurement. The measuring system and the results obtained are described in this paper. (auth.)

Superconducting linac beam dynamics with high-order maps for RF resonators

CERN Document Server

Geraci, A A; Pardo, R C; 10.1016/j.nima.2003.11.177

2004-01-01

The arbitrary-order map beam optics code COSY Infinity has recently been adapted to calculate accurate high-order ion-optical maps for electrostatic and radio-frequency accelerating structures. The beam dynamics of the superconducting low-velocity positive-ion injector linac for the ATLAS accelerator at Argonne National Lab is used to demonstrate some advantages of the new simulation capability. The injector linac involves four different types of superconducting accelerating structures and has a total of 18 resonators. The detailed geometry for each of the accelerating cavities is included, allowing an accurate representation of the on- and off-axis electric fields. The fields are obtained within the code from a Poisson-solver for cylindrically symmetric electrodes of arbitrary geometry. The transverse focusing is done with superconducting solenoids. A detailed comparison of the transverse and longitudinal phase space is made with the conventional ray-tracing code LINRAY. The two codes are evaluated for ease ...

Digital beam position and phase monitor for P-LINAC for FAIR

Energy Technology Data Exchange (ETDEWEB)

Almalki, Mohammed

2013-07-01

For the planned P-LINAC for the FAIR facility, Beam Position Monitors (BPM) will be installed at 14 locations along the LINAC. The digital signal processing to derive the transverse beam position and the beam phase will be implemented by ''Libera Single Pass H''. The specification for position measurement is 0.1 mm spatial resolution and phase accuracy is 1 degree with respect to 325 MHz acceleration frequency. The results from the Libera digital signal processing were compared with the time-domain approach and the FFT analytic calculations. The first test was performed at the GSI UNILAC with a Ne4+ beam at 1.4 MeV / u. A single BPM was used to act as a ''Bunch arrival monitor'' to characterize the dependence of beam arrival time on bunch shape. The signals were sampled at 117.440 MHz with a 16-bit ADC to produce I and Q data streams. The first experimental results are reported.

Three-dimensional space charge calculation method

International Nuclear Information System (INIS)

Lysenko, W.P.; Wadlinger, E.A.

1981-01-01

A method is presented for calculating space-charge forces suitable for use in a particle tracing code. Poisson's equation is solved in three dimensions with boundary conditions specified on an arbitrary surface by using a weighted residual method. Using a discrete particle distribution as our source input, examples are shown of off-axis, bunched beams of noncircular crosssection in radio-frequency quadrupole (RFQ) and drift-tube linac geometries

Neutron and photon spectra in LINACs

International Nuclear Information System (INIS)

Vega-Carrillo, H.R.; Martínez-Ovalle, S.A.; Lallena, A.M.; Mercado, G.A.; Benites-Rengifo, J.L.

2012-01-01

A Monte Carlo calculation, using the MCNPX code, was carried out in order to estimate the photon and neutron spectra in two locations of two linacs operating at 15 and 18 MV. Detailed models of both linac heads were used in the calculations. Spectra were estimated below the flattening filter and at the isocenter. Neutron spectra show two components due to evaporation and knock-on neutrons. Lethargy spectra under the filter were compared to the spectra calculated from the function quoted by Tosi et al. that describes reasonably well neutron spectra beyond 1 MeV, though tends to underestimate the energy region between 10 –6 and 1 MeV. Neutron and the Bremsstrahlung spectra show the same features regardless of the linac voltage. - Highlights: ► With MCNPX code realistic models of two LINACs were built. ► Photon and neutron spectra below the flattening filter and at the isocenter were calculated. ► Neutron spectrum at the flattening filter was compared against the Tosi et al. source-term model. ► Tosi et al. model underestimates the neutron contribution below 1 MeV. ► Photon spectra look alike to those published in literature.

Present status of the ETL LINAC facility

International Nuclear Information System (INIS)

Suzuki, Ryoichi; Mikado, Tomohisa; Ohgaki, Hideaki

1993-01-01

The ETL LINAC has been operated for the beam injection to the storage rings NIJI-II, III, IV, and TERAS, and for the generation of an intense slow positron beam. The status of the ETL LINAC on the operations, the maintenances, and the improvements is described. (author)

Fermilab 200 MeV linac control system hardware

Energy Technology Data Exchange (ETDEWEB)

Shea, M.F.

1984-01-01

This report is a description of the present Linac distributed control system that replaces the original Xerox computer and interface electronics with a network of 68000-based stations. In addition to replacing the obsolete Xerox equipment, goals set for the new system were to retain the fast response and interactive nature of the original system, to improve reliability, to ease maintenance, and to provide 15 Hz monitoring of all Linac parameters. Our previous experience with microcomputer installations showed that small, stand-alone control systems are rather straightforward to implement and have been proven to be reliable in operation, even in the severe environment of the 750-keV preaccelerator. The overall design of the Linac system incorporates the concept of many relatively small, stand-alone control systems networked together using an intercomputer communication network. Each station retains its local control system character but takes advantage of the network to allow an operator to interact with the entire Linac from any local console. At the same time, a link to the central computer system allows Host computers to also access parameters in the Linac.

Fermilab 200 MeV linac control system hardware

International Nuclear Information System (INIS)

Shea, M.F.

1984-01-01

This report is a description of the present Linac distributed control system that replaces the original Xerox computer and interface electronics with a network of 68000-based stations. In addition to replacing the obsolete Xerox equipment, goals set for the new system were to retain the fast response and interactive nature of the original system, to improve reliability, to ease maintenance, and to provide 15 Hz monitoring of all Linac parameters. Our previous experience with microcomputer installations showed that small, stand-alone control systems are rather straightforward to implement and have been proven to be reliable in operation, even in the severe environment of the 750-keV preaccelerator. The overall design of the Linac system incorporates the concept of many relatively small, stand-alone control systems networked together using an intercomputer communication network. Each station retains its local control system character but takes advantage of the network to allow an operator to interact with the entire Linac from any local console. At the same time, a link to the central computer system allows Host computers to also access parameters in the Linac

The invention that is shaping Linac4

CERN Multimedia

CERN Bulletin

2010-01-01

Accelerator experts are no strangers to innovative optimizations of existing techniques and to the development of novel solutions. Sometimes, they even come up with ideas that have the potential to revolutionize the field. This is the case with the Tolerance Aligned Cantilever Mounting (TACM) system, a completely new way of supporting the drift tubes, one of the core elements of linear accelerators. The new, patent-pending technique will be implemented at Linac4.   Drift tubes in a prototype for Linac4, assembled using the new TACM technology. “Assemble and adjust” – that was the technique used to build drift-tube linacs before the arrival of the TACM. Now, the inventors’ motto has become ‘adjust and assemble’. The inversion of these two words represents a real revolution for people working in the field. “The drift tubes are a critical element of Linac4 and they have to satisfy several requirements: they have to be mechanically ...

Beam dynamics of alternating-phase-focused linac

CERN Document Server

Iwata, Y; Kapin, V

2004-01-01

A simple method to find an array of synchronous phases for alternating-phase-focused (APF) linacs is presented. The phase array is described with a smooth function having free parameters. With a set of the parameters, a simulation on the beam dynamics was made and distributions of the six-dimensional phase spaces were calculated for each set of the parameters. The parameters were varied, and numbers of the simulations have been performed. An optimum set of the parameters were determined so that the simulations of the beam dynamics yield large acceptances and small emittances of the extracted beams. Since the APF linac can provide both axial and radial stability of beams just with the rf acceleration-field, no additional focusing element inside of drift tubes are necessary. Comparing with conventional linacs having focusing elements, it has advantage in construction and operation costs as well as its acceleration rate. Therefore, the APF linacs would be suited for an injector of medical synchrotrons. A practic...

Resonant excitation of high order modes in the 3.9 GHz cavity of the Linac Coherent Light Source

Directory of Open Access Journals (Sweden)

A. Lunin

2018-02-01

Full Text Available Construction of the Linac Coherent Light Source II (LCLS-II is underway for the world’s first hard x-ray free-electron laser. A central part of the LCLS-II project is a 4 GeV superconducting radio frequency electron linac that will operate in the continuous wave (cw mode. The linac is segmented into four sections named as L0, L1, L2, and L3. Two 3.9 GHz cryomodules, each housing of eight third-harmonic cavities similar to the cavities developed for the European X-ray Free Electron Laser (XFEL, will be used in section L1 of the linac for linearizing the longitudinal beam profile. In this paper, we present a study of trapped high order modes (HOMs excited by a cw electron beam in the third-harmonic cavities of the LCLS-II linac. A detailed comparison of the original XFEL design and the LCLS-II design with a modified end group is performed in order to estimate the effect of a reduced beam pipe aperture on the efficiency of HOM damping. Furthermore, we apply a statistical analysis of the eigenmode spectrum for the estimation of the probability of resonant HOM losses and influence of HOMs on beam dynamics.

Hearthfire design base for the high current low velocity rf linac

International Nuclear Information System (INIS)

Burke, R.J.; Khoe, T.K.; Kustom, R.L.; Martin, R.L.; Moretti, A.

1977-01-01

The particle beam parameters needed for inertial fusion can be achieved with conventional accelerator technology if heavy ion machines attain the level of performance of the most intense high energy proton machines. Many of the problems posed by this goal pertain to the low energy portions of the accelerator system. In particular, the implied particle current in the rf linac is 10 3 --10 4 times the values achieved with existing heavy ion machines. Much of this discrepancy is simply attributable to the great differences between the design considerations relevant to accelerators for fusion and those which have determined the performance of the existing machines. The basic concept chosen at Argonne National Laboratory is cavities containing single drift tubes mounted on lambda/4 supports. Such structures pose the least problem for the beam transport system, and one cavity is placed between adjacent quadrupole magnets. The average voltage gain of the first cells of the low velocity section is moderate; and, although probably acceptable and improved by the end of the 10 MV section, the low initial gain adds to the motivation provided by the transport problem to increase the preinjector voltage substantially above 750 kV

Some aspects of linacs as applied to the ISL benchmark facility

International Nuclear Information System (INIS)

Shepard, K.W.

1992-01-01

This paper considers several aspects of using linacs in a radioactive beam facility in terms of the Isospin Laboratory (ISL) Benchmark Facility (BMF) plan, described in the 1991 white paper for a possible radioactive-beam laboratory. The intention is not to review comprehensively the application of linacs to an ISL facility, but to compare in outline form several linac options for such a facility. Particular emphasis is given to the use of superconducting rf technology for the secondary beam accelerator. In what follows, first a possible normally-conducting light-ion linac for a primary beam accelerator is briefly outlined. Then the performance and cost of two options for a secondary beam accelerator are compared: a recent design for a normal-conducting cw linac, and an ATLAS-type superconducting linac. Finally, some of the problems which may be encountered at the entrance of a secondary beam linac are discussed

Measurement of the ground state spectroscopic quadrupole moments of 191Os and 193Os

International Nuclear Information System (INIS)

Ernst, H.; Hagn, E.; Zech, E.

1979-01-01

Radioactive 191 Os and 193 Os nuclei have been aligned in an Os single crystal at temperatures down to 4 mK. From the temperature dependence of the γ-anisotropy the quadrupole frequencies vsub(Q) = e 2 qQ/h have been determined as vsub(Q)( 191 OsOs) = -278+-9 MHz and vsub(Q)( 193 OsOs) = -96+-15 MHz. With the known electric field gradient for OsOs of eq = (-4.54+-0.24) x 10 17 V/cm 2 the ground state spectroscopic quadrupole moments are deduced to be Q( 191 Os) = +2.53+-0.16 b and Q( 193 Os) = +0.87+-0.15 b. (orig.)

Conceptual Design of the Superconducting Proton Linac Short Cryo-module

CERN Document Server

Bourcey, N; Capatina, O; Azevedo, P; Montesinos, E; Parma, V; Renaglia, T; Vande Craen, A; Williams, L R; Weingarten, W; Rousselot, S; Duthil, P; Duchesne, P; Reynet, D; Dambre, P

2012-01-01

The Superconducting Proton Linac (SPL) is an R&amp;amp;D effort conducted by CERN in partnership with other international laboratories, aimed at developing key technologies for the construction of a multi-megawatt proton linac based on state-of-the-art Superconducting Radio Frequency technology, which would serve as a driver for new physics facilities such as neutrinos and radioactive ion beams. Amongst the main objectives of this effort, are the development of 704 MHz bulk niobium b=1 elliptical cavities, operating at 2 K and providing an accelerating field of 25 MV/m, and testing of a string of cavities integrated in a machine-type cryo-module. In an initial phase only four out of the eight cavities of an SPL cryo-module will be tested in a ½ length cryo-module developed for this purpose, and therefore called the Short Cryo-module. This paper presents the conceptual design of the SC, highlighting its innovative principles in terms of cavity supporting and alignment, and describes the integratio...

Development plan of basic technology for a high intensity proton linear accelerator

International Nuclear Information System (INIS)

Mizumoto, M.

1990-01-01

The national program called OMEGA (Option Making Extra Gains from Actinide and Fission Products) has started with the aim of promoting the research and development of the new technologies for nuclear waste partitioning and transmutation. As a part of this program, Japan Atomic Energy Research Institute, JAERI, has laid out several R and D plans for accelerator based actinide transmutation. The present article first outlines the status of the high intensity proton linear accelerator. Then it describes the time schedule for the development of a high intensity proton linac, focusing on the first step development (basic technology accelerator), second step development (engineering test accelerator, and third step development (commercial plant). It also outlines the conceptual design study and preliminary design calculations for basic technology accelerator, focusing on general consideration, ion source, radio frequency quadrupole, drift tube linac, and high beta linac. (N.K.)

Challenges of the ILC Main Linac

International Nuclear Information System (INIS)

Ross, Marc

2007-01-01

With the completion of the ILC Reference Design Report (RDR), we begin the next phase of the project - development of the Engineering Design. Our strategy and priorities come from the identification, contained in the RDR, of scientific and engineering challenges of the ILC. First among these is the cost of the main linac which, including the associated earthworks and cooling/power systems, amounts to 60% of the ILC total cost. Next is the challenge to reach the highest practical gradient since this R and D has the largest cost leverage of any of the ongoing programs. Finally, we have to understand the beam dynamics and beam tuning processes in the main linac, as we will not have the opportunity to do full (or even large) scale tests of these before the linac is constructed.

Three-dimensional quadrupole lenses made with permanent magnets

International Nuclear Information System (INIS)

Ivanov, A.S.

1984-01-01

The performance of accelerator systems with quadrupole magnets can be improved by using permanent magnets in quadrupole lenses. This requires better methods for treating the three-dimensional nature of the magnetic fields and the nonlinear characteristics of the magnets. A numerical method is described for simulating three-dimensional magnetic fields and used to analyze quadrupole lenses and doublets with permanent magnets. The results, which are confirmed experimentally, indicate that both the quadrupole magnetic gradient and the effective field length are changed in permanent-magnet quadrupole lenses when the pole lengths and the gap between the lenses are varied while the other characteristics of the magnets remain unchanged

Radiation induced currents in MRI RF coils: application to linac/MRI integration

Science.gov (United States)

Burke, B.; Fallone, B. G.; Rathee, S.

2010-02-01

The integration of medical linear accelerators (linac) with magnetic resonance imaging (MRI) systems is advancing the current state of image-guided radiotherapy. The MRI in these integrated units will provide real-time, accurate tumor locations for radiotherapy treatment, thus decreasing geometric margins around tumors and reducing normal tissue damage. In the real-time operation of these integrated systems, the radiofrequency (RF) coils of MRI will be irradiated with radiation pulses from the linac. The effect of pulsed radiation on MRI radio frequency (RF) coils is not known and must be studied. The instantaneous radiation induced current (RIC) in two different MRI RF coils were measured and presented. The frequency spectra of the induced currents were calculated. Some basic characterization of the RIC was also done: isolation of the RF coil component responsible for RIC, dependence of RIC on dose rate, and effect of wax buildup placed on coil on RIC. Both the time and frequency characteristics of the RIC were seen to vary with the MRI RF coil used. The copper windings of the RF coils were isolated as the main source of RIC. A linear dependence on dose rate was seen. The RIC was decreased with wax buildup, suggesting an electronic disequilibrium as the cause of RIC. This study shows a measurable RIC present in MRI RF coils. This unwanted current could be possibly detrimental to the signal to noise ratio in MRI and produce image artifacts.

LINAC4, A New $H^{-}$ Linear Injector at CERN

CERN Document Server

Garoby, R; Hanke, K; Lombardi, A M; Rossi, C; Vretenar, M

2004-01-01

Linac2, the present injector of the CERN PS Booster, limits the performance of the proton accelerator complex because of its low output energy (50 MeV). To remove this bottleneck, a higher energy linac is proposed (called â€ﾜLinac4†) which will double the brightness and the intensity of the beam delivered by the PSB and ensure the â€ﾜultimate” beam is available for LHC. Linac4 will deliver H- ions at a kinetic energy of 160 MeV. It is designed to be usable as the front-end of a future multi-GeV multi-MW linear accelerator, the â€ﾜSuperconducting Proton Linac” (SPL). R&D for Linac4 is now actively taking place with the support of the European Union through the Joint Research Activity HIPPI (â€ﾜHigh Intensity Pulsed Proton Injectors”), and of three ISTC projects involving three major Russian laboratories (BINP, IHEP and ITEP) and two nuclear centres (VNIIEF and VNIITF). The design of this new accelerator and the on-going developments are described.

Status and plans for Linac4 installation and commissioning

CERN Document Server

Vretenar, M; Arnaudon, L; Baudrenghien, P; Bellodi, G; Broere, J; Brunner, O; Comblin, J F; Coupard, J; Dimov, V A; Fuchs, J F; Funken, A; Gerigk, F; Granemann Souza, E; Hanke, K; Hansen, J; Yarmohammadi Satri, M; Kozsar, I; Lallement, J B; Lenardon, F; Lettry, J; Lombardi, A M; Maglioni, C; Midtun, O; Mikulec, B; Nisbet, D; Paoluzzi, M; Raich, U; Ramberger, S; Roncarolo, F; Rossi, C; Sanchez Alvarez, J L; Scrivens, R; Tan, J; Valerio-Lizarraga, C A; Vollaire, J; Wegner, R; Weisz, S; Zocca, F

2014-01-01

Linac4 is a normal conducting 160 MeV Hˉ 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 take place in 2016, prior to...

Frequency scaling of linear super-colliders

International Nuclear Information System (INIS)

Mondelli, A.; Chernin, D.; Drobot, A.; Reiser, M.; Granatstein, V.

1986-06-01

The development of electron-positron linear colliders in the TeV energy range will be facilitated by the development of high-power rf sources at frequencies above 2856 MHz. Present S-band technology, represented by the SLC, would require a length in excess of 50 km per linac to accelerate particles to energies above 1 TeV. By raising the rf driving frequency, the rf breakdown limit is increased, thereby allowing the length of the accelerators to be reduced. Currently available rf power sources set the realizable gradient limit in an rf linac at frequencies above S-band. This paper presents a model for the frequency scaling of linear colliders, with luminosity scaled in proportion to the square of the center-of-mass energy. Since wakefield effects are the dominant deleterious effect, a separate single-bunch simulation model is described which calculates the evolution of the beam bunch with specified wakefields, including the effects of using programmed phase positioning and Landau damping. The results presented here have been obtained for a SLAC structure, scaled in proportion to wavelength

Fermilab Linac Upgrade Conceptual Design: Revision 3

Energy Technology Data Exchange (ETDEWEB)

None, None

1989-07-01

The goal of the Tevatron Collider Upgrade program is to improve the Collider luminosity and the fixed-target intensity. The Linac portion of this project will increase the energy of the existing 200- MeV linac to 400 MeV in order to reduce beam emittance degradation in the Booster.

Design of an electrostatic magnetic quadrupole accelerator

International Nuclear Information System (INIS)

Mizuno, M.; Ohara, Y.

1993-01-01

A new type of electrostatic acceleration system, electrostatic magnetic quadrupole (ESMQ) acceleration system, is proposed for efficient acceleration of negative ion beams. In this system, permanent magnets are buried in the acceleration electrodes so as to produce a quadrupole magnetic field in the electrode aperture region. Envelope simulation indicates that the quadrupole field can deflect electrons stripped from the negative ions. Beam envelope simulations for deuterium ions and electrons have been carried out using the beam envelope code TRACE. Electrons are largely divergent and most appear likely to hit downstream electrodes. Furthermore, maximum beam divergence of the deuterium ions is reduced to the focusing effect of the quadrupole magnetic field

High gradient superconducting quadrupoles

International Nuclear Information System (INIS)

Lundy, R.A.; Brown, B.C.; Carson, J.A.; Fisk, H.E.; Hanft, R.H.; Mantsch, P.M.; McInturff, A.D.; Remsbottom, R.H.

1987-07-01

Prototype superconducting quadrupoles with a 5 cm aperture and gradient of 16 kG/cm have been built and tested as candidate magnets for the final focus at SLC. The magnets are made from NbTi Tevatron style cable with 10 inner and 14 outer turns per quadrant. Quench performance and multipole data are presented. Design and data for a low current, high gradient quadrupole, similar in cross section but wound with a cable consisting of five insulated conductors are also discussed

Brookhaven Linac Isotope Producer

Data.gov (United States)

Federal Laboratory Consortium — The Brookhaven Linac Isoptope Producer (BLIP)—positioned at the forefront of research into radioisotopes used in cancer treatment and diagnosis—produces commercially...

Electrostatic quadrupoles for heavy-ion fusion

International Nuclear Information System (INIS)

Seidl, P.; Faltens, A.

1993-05-01

Voltage-holding data for three quadrupole electrode sizes and inter-electrode spacings are reported. The dependence of the breakdown voltage on system size and its influence on the optimum quadrupole size for beam transport in a multiple beam array are discussed

Minimum beam-energy spread of a high-current rf linac

International Nuclear Information System (INIS)

Chan, K.C.D.; Fraser, J.S.

1987-01-01

Energy spread is an important parameter of an electron linac and, usually, is determined by the time dependence of the external rf accelerating field. By using a combination of fundamental and higher harmonic frequencies, the accelerating field can be maintained approximately constant over a beam bunch with the resultant energy spread approximately zero. This technique is no longer adequate when the longitudinal wake field of the beam bunch is taken into account. The wake-field variation along the bunch length introduces an energy spread that cannot be exactly compensated for with the use of fundamental and higher harmonic frequencies. The achievable minimum energy spread including the wake-field effect is therefore limited. In this paper, we report the minimum energy spreads achievable using the fundamental and third-harmonic frequencies, calculated using a least-squares algorithm, for some typical structures in use at Los Alamos National Laboratory. The dependence of these results on bunch shape, bunch charge, and structure frequency is discussed. Also included are discussions of schemes for implementing the third-harmonic frequency and their effectiveness

Two qubits in pure nuclear quadrupole resonance

International Nuclear Information System (INIS)

Furman, G.B.; Goren, S.D.; Meerovich, V.M.; Sokolovsky, V.L.

2002-01-01

It is shown theoretically that by the use of two radio-frequency fields of the same resonance frequency but with the different phases and directions the degeneracy of the energy spectrum of a spin system with I=3/2 is removed. This leads to four non-degenerate spin states which can be used as a platform for quantum computing. The feasibility of quantum computing based on a pure (without DC magnetic fields) nuclear quadrupole resonance technique is investigated in detail. Various quantum logic gates can be constructed by using different excitation techniques allowing different manipulations with the spin system states. Three realizations of quantum logic gates are considered: the application of an additional magnetic field with the resonance frequency, the amplitude modulation of one of the applied RF fields by the resonance frequency field, and the level-crossing method. It is shown that the probabilities of the resonance transitions depend on the method of excitation and on the direction of the excitation field. Feasibility of quantum computing is demonstrated with the examples of constructing a controlled-NOT logic gate using the resonance excitation technique and SWAP and NOT2 logic gates using the level-crossing method. (author)

Heavy ion induction linacs for fusion

International Nuclear Information System (INIS)

Bangerter, R.O.; Ho, D.D.M.

1991-01-01

In 1976 Denis Keefe proposed the heavy ion induction linac as a driver for inertial confinement fusion (ICF) power plants. Subsequent research has established that heavy ion fusion (HIF) is potentially an attractive energy source and has identified the issues that must be resolved to make HIF a reality. The principal accelerator issues are achieving adequately low transverse and longitudinal emittance and acceptable cost. Results from the single and multiple beam experiments at LBL on transverse emittance are encouraging. A predicted high current longitudinal instability that can affect longitudinal emittance is currently being studied. This paper presents an overview of economics and ICF target requirements and their relationship to accelerator design. It also presents a summary of the status of heavy ion induction linac research. It concludes with a discussion of research plans, including plans for the proposed Induction Linac Systems Experiments (ILSE)

Development of the High Energy Linac Systems

International Nuclear Information System (INIS)

Cho, Yong Sub; Kwon, Hyeok Jung; Kim, Han Sung; Chung, Byung Chul; Jang, Ji Ho; Gao, Changgi; Li, Yingmin; Sun, An; Tang, Yazhe; Zhang, Lipoing; Hwang, Yong Seok

2008-05-01

The main purpose of this project is studying the extension plan of the proton engineering frontier project (PEFP) 100-MeV Linac. It includes three categories. One is studying operation plan of the PEFP linac and its extended accelerators, and developing a distribution system of 100-MeV proton beams with a laser striping. Other is designing superconducting RF (SRF) modules and fabricating and testing a copper cavity model. The other is designing a rapid cycling synchrotron (RCS). The operation scheme of the PEFP linac is related to the optimization in the operation of the 100-MeV linac, 200-MeV SRF, and RCS. We studied several operational method to increase the validity of the accelerators. The beam distribution system has two roles. One is supplying proton beams of 100 MeV to the user group. The laser stripping of the negative hydrogen atoms is used in this case. The other beams are directed to the next high energy accelerators. This study contributes to increase the availability of the proton beams. The SRF is one of candidates to extend the PEFP linac system. Since the accelerating gradient of the SRF is much higher than the normal conducting accelerator, a lot of institutes over the world are developing the SRF structure. Main purposes are designing an SRF module, fabricating and testing an copper model which has similar material properties as Nb of the usual SRF cavity material. The RCS is a synchrotron whose injector is the PEFP 100-MeV linac. Main purposes are determining the lattice structure, studying the fast and slow extraction system, simulating beam behavior in the designed synchrotron. The RCS will be used as the spallation neutron source and tools in the basic and applied science including medical application

Solid state NMR, basic theory and recent progress for quadrupole nuclei with half-integer spin

International Nuclear Information System (INIS)

Dieter, F.

1998-01-01

This review describes the basic theory and some recently developed techniques for the study of quadrupole nuclei with half integer spins in powder materials. The latter is connected to the introduction of the double rotation (DOR) by A. Samoson et al. (1) and to the introduction of the multiple quantum magic-angle spinning (MQ MAS) technique by L. Frydman et. al. (2). For integer spins, especially the solid-state deuterium magnetic resonance, we refer to the review of G.L. Hoatson and R.L. Vold: '' 2 H-NMR Spectroscopy of Solids and Liquid Crystals'' (3). For single crystals we refer to O. Kanert and M. Mehring: ''Static quadrupole effects in disordered cubic solids''(4) and we would like also to mention the ''classic'' review of M.H. Cohen and F. Reif: ''Quadrupole effects in NMR studies of solids'' (5). Some more recent reviews in the field under study are D. Freude and J. Haase ''Quadrupole effects in solid-state NMR'' (6). Ch. Jager: ''Satellite Transition Spectroscopy of Quadrupolar Nuclei'' (7) and B.F. Chmelka and J.W. Zwanziger: ''Solid State NMR Line Narrowing Methods for Quadrupolar Nuclei - Double Rotation and Dynamic-Angle Spinning'' (8). A survey of nuclear quadrupole frequency data published before the end of 1982 is given by H. Chihara and N. Nakamura in Landolt-Bornstein, Vol. 20 (9). Values of the chemical shift of quadrupole nuclei in solids can be found in books such as ''Multinuclear NMR'' edited by J. Mason (10). In section 9 of ref (6) some electric field gradient and chemical shift data published from 1983 to 1992 for the most studied quadrupole nuclei sup 27 Al, sup 23 Na, and sup 17 O are given

Nuclear quadrupole resonance of 93Nb in ternary phases on the bases of Nb3Al compound

International Nuclear Information System (INIS)

Matukhin, V.L.; Safin, I.A.; Shamraj, V.F.

1980-01-01

Results of investigations into concentration dependences of 93 Nb spectrum parameters of nuclear quadrupole resonance (n.g.r.) (frequencies of n.g.r. transitions, rates of nuclear spin - lattice relaxation R) in triple phases which appear as a result of Nb 3 Al compound alloying with Zr, Ga, Sn, are presented. Nb 3 Al alloying with gallium does not considerably change the R value (R-rate of nuclear spin - lattice relaxation, while alloying with zirconium decreases it to a noticeable extent. It is 30% less in the triple phase than in the Nb 3 Al compound. R alterations, frequency reduction in the 93 Nb n.q.r. spectrum and the decrease of constant of the quadrupole bond point to the alteration of the spatial electron distribution around a niobium atom during alloying [ru

Electro neutrons around a 12 MV Linac

International Nuclear Information System (INIS)

Vega C, H. R.; Perez L, L. H.

2012-10-01

Neutron contamination around Linacs for radiotherapy is a source of undesirable doses for the patient. The main source of these neutrons is the photonuclear reactions occurring in the Linac head and the patient body. Electrons also produce neutrons through (e, en) reactions. This reaction is known as electro disintegration and is carried out by the electron scattering that produce a virtual photon that is absorbed by the scattering nucleus producing the reaction e + A → (A-1) + n + e'. In this work the electron-neutron spectrum to 100 cm from the isocenter of a 12 MV Linac has been measured using a passive Bonner spheres spectrometer in a novel procedure named Planetary mode. (Author)

Improvements on monitor system in the KEK 2.5-GeV linac

International Nuclear Information System (INIS)

Shidara, T.; Oogoe, T.; Ogawa, Y.

1989-01-01

Improvements to the monitor system of the KEK 2.5-GeV linac have been undertaken. Energy analyzing stations were added to both the positron generator linac and the 2.5-GeV electron linac in order to realize easier checking of beam energy. Wall current monitors and profile monitors were added in the beam transport line between the positron generator linac and the 2.5-GeV electron linac in order to realize easier positron-beam transfer. As a result of the installation of an automatic beam-current-surveillance system and with other existing surveillance systems, more reliable and easier operation of the linac is expected. (author)

Physics design of a 10 MeV, 6 kW travelling wave electron linac for industrial applications

International Nuclear Information System (INIS)

Kulkarni, Nita S.; Dhingra, Rinky; Kumar, Vinit

2016-01-01

We present the physics design of a 10 MeV, 6 kW S-band (2856 MHz) electron linear accelerator (linac), which has been recently built and successfully operated at Raja Ramanna Centre for Advanced Technology, Indore. The accelerating structure is a 2π/3 mode constant impedance travelling wave structure, which comprises travelling wave buncher cells, followed by regular accelerating cells. The structure is designed to accelerate 50 keV electron beam from the electron gun to 10 MeV. This paper describes the details of electromagnetic design simulations to fix the mechanical dimensions and tolerances, as well as heat loss calculations in the structure. Results of design simulations have been compared with those obtained using approximate analytical formulae. The beam dynamics simulation with space charge is performed and the required magnetic field profile for keeping the beam focussed in the linac has been evaluated and discussed. An important feature of a travelling wave linac (in contrast with standing wave linac) is that it accepts the RF power over a band of frequencies. Three dimensional transient simulations of the accelerating structure along with the input and output couplers have been performed using the software CST-MWS to explicitly demonstrate this feature. (author)

Application of superconductivity to intense proton linacs

International Nuclear Information System (INIS)

Heinrichs, H.

1996-01-01

Three examples of proposed superconducting linacs for intense particle beams are presented, and in two cases compared to normal conducting counterparts. Advantages and disadvantages of both types are discussed. Suggestions for future developments are presented. Finally a comparison of estimated operational costs of the normal and the superconducting linac for the ESS is given. (R.P.)

A strong focussing cylindrical electrostatic quadrupole

International Nuclear Information System (INIS)

Sheng Yaochang

1986-01-01

The construction and performance of small cylindrical electrostatic quadrupole, which is installed in JM-400 pulse electrostatic accelerator, are described. This electrostatic quadrupole is not only used in neutron generator, but also suitable for ion injector as well as for low energy electron accelerator

A novel electron gun for inline MRI-linac configurations

International Nuclear Information System (INIS)

Constantin, Dragoş E.; Fahrig, Rebecca; Holloway, Lois; Keall, Paul J.

2014-01-01

Purpose: This work introduces a new electron gun geometry capable of robust functioning in the presence of a high strength external magnetic field for axisymmetric magnetic resonance imaging (MRI)-linac configurations. This allows an inline MRI-linac to operate without the need to isolate the linear accelerator (linac) using a magnetic shield. This MRI-linac integration approach not only leaves the magnet homogeneity unchanged but also provides the linac flexibility to move along the magnet axis of symmetry if the source to target distance needs to be adjusted. Methods: Simple electron gun geometry modifications of a Varian 600C electron gun are considered and solved in the presence of an external magnetic field in order to determine a set of design principles for the new geometry. Based on these results, a new gun geometry is proposed and optimized in the fringe field of a 0.5 T open bore MRI magnet (GE Signa SP). A computer model for the 6 MeV Varian 600C linac is used to determine the capture efficiency of the new electron gun-linac system in the presence of the fringe field of the same MRI scanner. The behavior of the new electron gun plus the linac system is also studied in the fringe fields of two other magnets, a 1.0 T prototype open bore magnet and a 1.5 T GE Conquest scanner. Results: Simple geometrical modifications of the original electron gun geometry do not provide feasible solutions. However, these tests show that a smaller transverse cathode diameter with a flat surface and a slightly larger anode diameter could alleviate the current loss due to beam interactions with the anode in the presence of magnetic fields. Based on these findings, an initial geometry resembling a parallel plate capacitor with a hole in the anode is proposed. The optimization procedure finds a cathode-anode distance of 5 mm, a focusing electrode angle of 5°, and an anode drift tube length of 17.1 mm. Also, the linac can be displaced with ±15 cm along the axis of the 0.5 T

University of Washington superconducting booster linac

International Nuclear Information System (INIS)

Storm, D.W.; Amsbaugh, J.F.; Cramer, J.G.; Swanson, H.E.; Trainor, T.A.; Vandenbosch, R.; Weitkamp, W.G.; Will, D.I.

1985-01-01

We have begun construction of a superconducting linac designed to accelerate ions from protons through about mass 60. Injected by our 9 MV-terminal tandem van de Graaff accelerator, the linac is expected to double the proton energy and quadruple the energies of heavier ions. The resonators are lead plated copper quarter wave structures. The overall layout and expected performance of the accelerator will be presented, along with a brief status report. 3 refs., 3 figs

An energy recovery electron linac-on-ring collider

International Nuclear Information System (INIS)

Merminga, L.; Krafft, G.A.; Lebedev, V.A.; Ben-Zvi, I.

2000-01-01

We present the design of high-luminosity electron-proton/ion colliders in which the electrons are produced by an Energy Recovering Linac (ERL). Electron-proton/ion colliders with center of mass energies between 14 GeV and 100 GeV (protons) or 63 GeV/A (ions) and luminosities at the 10 33 (per nucleon) level have been proposed recently as a means for studying hadronic structure. The linac-on-ring option presents significant advantages with respect to: (1) spin manipulations (2) reduction of the synchrotron radiation load in the detectors (3) a wide range of continuous energy variability. Rf power and beam dump considerations require that the electron linac recover the beam energy. Based on extrapolations from actual measurements and calculations, energy recovery is expected to be feasible at currents of a few hundred mA and multi-GeV energies. Luminosity projections for the linac-ring scenario based on fundamental limitations are presented. The feasibility of an energy recovery electron linac-on-proton ring collider is investigated and four conceptual point designs are shown corresponding to electron to proton energies of: 3 GeV on 15 GeV, 5 GeV on 50 GeV and 10 GeV on 250 GeV, and for gold ions with 100 GeV/A. The last two designs assume that the protons or ions are stored in the existing RHIC accelerator. Accelerator physics issues relevant to proton rings and energy recovery linacs are discussed and a list of required R and D for the realization of such a design is presented

Measurements of the microwave spectrum, Re-H bond length, and Re quadrupole coupling for HRe(CO)5

Science.gov (United States)

Kukolich, Stephen G.; Sickafoose, Shane M.

1993-11-01

Rotational transition frequencies for rhenium pentacarbonyl hydride were measured in the 4-10 GHz range using a Flygare-Balle type microwave spectrometer. The rotational constants and Re nuclear quadrupole coupling constants for the four isotopomers, (1) H187Re(CO)5, (2) H185Re(CO)5, (3) D187Re(CO)5, and (4) D185Re(CO)5, were obtained from the spectra. For the most common isotopomer, B(1)=818.5464(2) MHz and eq Q(187Re)=-900.13(3) MHz. The Re-H bond length (r0) determined by fitting the rotational constants is 1.80(1) Å. Although the Re atom is located at a site of near-octahedral symmetry, the quadrupole coupling is large due to the large Re nuclear moments. A 2.7% increase in Re quadrupole coupling was observed for D-substituted isotopomers, giving a rather large isotope effect on the quadrupole coupling. The Cax-Re-Ceq angle is 96(1)°, when all Re-C-O angles are constrained to 180°.

A Pencil Beam for the Linac4 commissioning

CERN Document Server

Lallement, JB

2010-01-01

In order to characterize the different accelerating structures and transport lines of Linac4 and to proceed to its commissioning, we need to produce a low current, low emittance beam. This note describes the generation of two pencil beams and their dynamic through the Linac.

High frequency CARM driver for RF linacs. Progress report, Year 1

International Nuclear Information System (INIS)

Danly, B.G.

1990-01-01

Progress during the first year of this program has been noteworthy in both theoretical and experimental areas. Substantial improvements to the MIT CARM codes have been carried out, and the code has been successfully benchmarked against other codes, linear theory, and experimental work. CARM amplifier phase stability has been studied theoretically and found to be significantly better than that of free-electron lasers or relativistic klystrons, provided the device is properly designed. Both multimode simulations and particle-in-cell simulations have been carried out to study mode competition effects between convectively unstable and absolutely unstable modes. Improvement of the Pierce-Wiggler code for modeling the beam formation prior to the interaction region has been carried out. Experimental designs for a long-pulse, modulator-driven CARM amplifier experiment which will be carried out by the end of this fiscal year have been mostly completed. Designs for an induction-linac-driven CARM amplifier experiment, which will be carried out by the end of Year II of this program,, have also been performed. Finally, a CARM oscillator experiment is presently underway at our facility

Double-photoionization of helium including quadrupole radiation effects

Energy Technology Data Exchange (ETDEWEB)

Colgan, James [Los Alamos National Laboratory; Ludlow, J A [AUBURN UNIV; Lee, Teck - Ghee [AUBURN UNIV; Pindzola, M S [AUBURN UNIV; Robicheaux, F [AUBURN UNIV

2009-01-01

Non-perturbative time-dependent close-coupling calculations are carried out for the double photoionization of helium including both dipole and quadrupole radiation effects. At a photon energy of 800 eV, accessible at CUlTent synchrotron light sources, the quadrupole interaction contributes around 6% to the total integral double photoionization cross section. The pure quadrupole single energy differential cross section shows a local maxima at equal energy sharing, as opposed to the minimum found in the pure dipole single energy differential cross section. The sum of the pure dipole and pure quadrupole single energy differentials is insensitive to non-dipole effects at 800 eV. However, the triple differential cross section at equal energy sharing of the two ejected electrons shows strong non-dipole effects due to the quadrupole interaction that may be experimentally observable.

Linac design for the European spallation source

Energy Technology Data Exchange (ETDEWEB)

Klein, H. [Universitaet Postfach, Frankfurt am Main (Germany)

1995-10-01

A study group has started to develop a conceptual design for a European Spallation Source (ESS). This pulsed 5 MW source presently consists of a 1.334 GeV linac and two compressor rings. In the following mainly the high intensity linac part will be discussed, which has some features of interest for accelerators for transmutation of radioactive waste too.

The Features of Moessbauer Spectra of Hemoglobins: Approximation by Superposition of Quadrupole Doublets or by Quadrupole Splitting Distribution?

International Nuclear Information System (INIS)

Oshtrakh, M. I.; Semionkin, V. A.

2004-01-01

Moessbauer spectra of hemoglobins have some features in the range of liquid nitrogen temperature: a non-Lorentzian asymmetric line shape for oxyhemoglobins and symmetric Lorentzian line shape for deoxyhemoglobins. A comparison of the approximation of the hemoglobin Moessbauer spectra by a superposition of two quadrupole doublets and by a distribution of the quadrupole splitting demonstrates that a superposition of two quadrupole doublets is more reliable and may reflect the non-equivalent iron electronic structure and the stereochemistry in the α- and β-subunits of hemoglobin tetramers.

Design and construction of the main linac module for the superconducting energy recovery linac project at Cornell

Energy Technology Data Exchange (ETDEWEB)

Eichhorn, R.; Bullock, B.; He, Y.; Hoffstaetter, G.; Liepe, M.; O' Connell, T.; Quigley, P.; Sabol, D.; Sears, J.; Smith, E.; Veshcherevich, V. [Cornell Laboratory for Accelerator-based Science and Education (CLASSE), Cornell University, 161 Synchrotron Drive, Ithaca, NY 14853 (United States)

2014-01-29

Cornell University has been designing and building superconducting accelerators for various applications for more than 50 years. Currently, an energy-recovery linac (ERL) based synchrotron-light facility is proposed making use of the existing CESR facility. As part of the phase 1 R and D program funded by the NSF, critical challenges in the design were addressed, one of them being a full linac cryo-module. It houses 6 superconducting cavities- operated at 1.8 K in continuous wave (CW) mode - with individual HOM absorbers and one magnet/ BPM section. Pushing the limits, a high quality factor of the cavities (2⋅10{sup 10}) and high beam currents (100 mA accelerated plus 100 mA decelerated) are targeted. We will present the design of the main linac cryo-module (MLC) being finalized recently, its cryogenic features and report on the status of the fabrication which started in late 2012.

Piezoelectric actuator based phase locking system to improve the dynamics of the control scheme for a heavy ion superconducting linac

Energy Technology Data Exchange (ETDEWEB)

Sahu, B.K., E-mail: bhuban@iuac.res.in [Inter University Accelerator Centre (IUAC), Aruna Asaf Ali Marg, New Delhi – 110 067 (India); Ahuja, R.; Kumar, Rajesh; Suman, S.K.; Mathuria, D.S.; Rai, A.; Patra, P.; Pandey, A.; Karmakar, J.; Chowdhury, G.K.; Dutt, R.N. [Inter University Accelerator Centre (IUAC), Aruna Asaf Ali Marg, New Delhi – 110 067 (India); Joshi, G. [Electronics Division, Bhabha Atomic Research Centre, Mumbai – 400 085 (India); Ghosh, S.; Kanjilal, D.; Roy, A. [Inter University Accelerator Centre (IUAC), Aruna Asaf Ali Marg, New Delhi – 110 067 (India)

2015-03-21

The superconducting heavy ion linear accelerator at Inter-University Accelerator Centre Delhi has been in operation since 2007. Initially, the superconducting niobium Quarter Wave Resonators (QWRs) in the linac were phase locked using a combination of electronic and mechanical controls which operated in fast (~10 μsec) and slow (~sec) time scales respectively. In this scheme, fast control was achieved through dynamic phase control whereas slow control of the frequency was done through the niobium tuner bellows installed at the drift tube end of the resonator and flexed using helium gas to change the resonance frequency. In order to improve the dynamics of this control system, an alternate scheme using piezoelectric actuator, instead of helium gas, to flex the same niobium bellows, has been implemented in the QWRs of the second and third accelerating modules of the linac. The piezoelectric actuator is used in closed loop along with the fast dynamic phase control scheme. The feedback loop of the piezoelectric control includes a dual control scheme - an integral control loop to arrest the slow drift, and the positive position feedback (PPF) based control loop to damp the microphonics. This control scheme has been found to arrest slow drifts in the resonator frequency more tightly along with damping of low frequency microphonics (~few tens of Hz) picked up by the resonator from its surrounding environment. This has substantially eased the load from the fast electronic control, resulting in the reduction of the radio frequency (RF) power requirement during operation. In addition, it has improved the stability of phase and amplitude of the QWRs. The details of the new scheme along with results obtained during the online run of the linac for beam acceleration are presented.

High-brightness electron guns for linac-based light sources

International Nuclear Information System (INIS)

Lewellen, J.W.

2004-01-01

Most proposed linac-based light sources, such as single-pass free-electron lasers and energy-recovery-linacs, require very high-brightness electron beams in order to achieve their design performance. These beam requirements must be achieved not on an occasional basis, but rather must be met by every bunch produced by the source over extended periods of time. It is widely assumed that the beam source will be a photocathode electron gun; the selection of accelerator technique (e.g., dc or rf) for the gun is more dependent on the application.The current state of the art of electron beam production is adequate but not ideal for the first generation of linac-based light sources, such as the Linac Coherent Light Source (LCLS) x-ray free-electron laser (X-FEL). For the next generation of linac-based light sources, an order of magnitude reduction in the transverse electron beam emittance is required to significantly reduce the cost of the facility. This is beyond the present state of the art, given the other beam properties that must be maintained. The requirements for current and future linac-based light source beam sources are presented here, along with a review of the present state of the art. A discussion of potential paths towards meeting future needs is presented at the conclusion.

Overview of High Intensity Linac Programs in Europe

CERN Document Server

Garoby, R

2004-01-01

Recent years have seen a boost in the support by the European Union (EU) of accelerator research in Europe. Provided they coordinate their efforts and define common goals and strategies, laboratories and institutions from the member states can receive a financial support reaching 50% of the total project cost. In the field of High Intensity Linacs, the EU has already supported the EURISOL initiative for nuclear physics, which this year is applying for funding of a Design Study, and the development of linacs for Waste Transmutation. More recently, an initiative for high-energy physics has been approved, which includes a programme for the development of pulsed linac technologies. The coordination and synergy imposed by the EU rules increase the benefit of the allocated resources. Combined with the ongoing internal projects in the partner laboratories, these European initiatives represent a strong effort focussed towards the development of linac technologies. This paper summarises the requests from the various E...

Linac4: injecting new life into the LHC

CERN Multimedia

Antonella Del Rosso

2015-01-01

Construction work is nearing completion on the ion source for Linac4, the new linear accelerator that forms part of the LHC injector upgrade programme. Here we find out more about this essential component of the accelerator chain, designed and built at CERN.     The image shows the Linac4 H- source. The red light is the alpha line of the visible hydrogen emission spectrum. The ion source is a key component of Linac4, the linear accelerator that from 2018 will supply H- ions (hydrogen atoms with an extra electron) at 160 MeV for injection into the accelerator complex. As the only ion source at CERN, Linac4 must be highly reliable, which requires a full understanding of the production mechanisms, the simulation of physical processes and the validation of those processes through experimentation. “This source is the result of much fruitful collaboration,” says Jacques Lettry of the BE department. “Its design was inspired by the many sources of th...

Conceptual Design of the Linac4 Main Dump

CERN Document Server

Leitao, I V; Maglioni, C

2012-01-01

Linac4 is the new CERN linear accelerator intended to replace the ageing Linac2 as the injector to the Proton Synchrotron Booster (PSB) for increasing the luminosity of the Large Hadron Collider (LHC). By delivering a 160MeV H- beam, Linac4 will provide the necessary conditions to double the brightness and intensity of the beam extracted from the PSB. This paper describes the conceptual design of the Linac4 Main Dump, where two different concepts relying respectively on water and air cooling were compared and evaluated. Based on the application of analytical models for the energy deposited by the beam, heat conduction and cooling concepts, a parametric study was performed. This approach allowed the identification of the “optimal” configuration for these two conceptual geometries and their relative comparison. Besides giving the theoretical guidelines for the design of the new dump, this work also contributes to the development of analytical tools to allow a better understanding of the influence of the se...

Thermogravimetric-quadrupole mass-spectrometric analysis of geochemical samples.

Science.gov (United States)

Gibson, E. K., Jr.; Johnson, S. M.

1972-01-01

Thermogravimetric-quadrupole mass-spectrometric-analysis techniques can be used to study a wide variety of problems involving decomposition processes and identification of released volatile components. A recording vacuum thermoanalyzer has been coupled with a quadrupole mass spectrometer. The rapid scan capabilities of the quadrupole mass spectrometer are used to identify the gaseous components released. The capability of the thermogravimetric-quadrupole mass spectrometer to provide analytical data for identification of the released volatile components, for determination of their sequence of release and for correlation of thermal-decomposition studies is illustrated by an analysis of the Orgueil carbonaceous chondrite.

Preinjector for Linac 1, Faraday cage

CERN Multimedia

1974-01-01

The 50 MeV Linac 1 started up in 1958 as injector to the 26 GeV PS, with a 520 kV Cockcroft-Walton generator as its preinjector, housed in a vast Faraday cage, visible here. When the Cockcroft-Walton broke down in 1973, it was replaced by a much smaller SAMES generator, of the kind used for electrostatic separators. From 1980 on, Linac 2 took over as injector for the 800 MeV Booster, and Linac 1 continued as injector for LEAR. In 1984, the electrostatic preinjector (i.e. the Faraday cage with its contents, SAMES generator and all) was replaced by a 520 keV RFQ. At the lower left corner we see the HV connectors to the SAMES generator, at the right edge part of the opened electronics-platform. Jean-Luc Vallet sees to it that all parts are properly grounded. See also 7403073X, 7403074X, 7403081X, 7403083X.

An induction Linac driven heavy-ion fusion systems model

International Nuclear Information System (INIS)

Zuckerman, D.S.; Driemeyer, D.E.; Waganer, L.M.; Dudziak, D.J.

1988-01-01

A computerized systems model of a heavy-ion fusion (HIF) reactor power plant is presented. The model can be used to analyze the behavior and projected costs of a commercial power plant using an induction linear accelerator (Linac) as a driver. Each major component of the model (targets, reactor cavity, Linac, beam transport, power flow, balance of plant, and costing) is discussed. Various target, reactor cavity, Linac, and beam transport schemes are examined and compared. The preferred operating regime for such a power plant is also examined. The results show that HIF power plants can compete with other advanced energy concepts at the 1000-MW (electric) power level [cost of electricity (COE) -- 50 mill/kW . h] provided that the cost savings predicted for Linacs using higher charge-state ions (+3) can be realized

Discussion of superconducting and room-temperature high-intensity ion linacs

International Nuclear Information System (INIS)

Jameson, R.A.

1996-01-01

The point of view taken in this discussion is that the basic technology base exists in all essential respects for both superconducting or room-temperature rf linac accelerators and associated power and control systems, and thus a project can make a choice between these technologies on overall system considerations. These include performance, cost, availability, flexibility, and upgradability. Large high-intensity neutron source proposals involving light-ion rf linacs in three categories are reviewed in this context. The categories arc cw linacs to high (∼1 GeV) and low (∼40 MeV) output energy, and pulsed linacs to energy ∼1 GeV

New linac technology - for SSC, and beyond

International Nuclear Information System (INIS)

Jameson, R.A.

1983-01-01

With recent agreement on the high priority of seeking funding for a Superconducting Super Collider (SSC), it is appropriate to consider the injector linac requirements for such a machine. In so doing, the status of established technique and advantages of near-term R and D with relatively clear payoff are established, giving a base line for some speculation about linac possibilities even further in the future

Source and LINAC3 studies

CERN Document Server

Bellodi, G

2017-01-01

In the framework of the LHC Ion Injector Upgrade pro-gramme (LIU), several activities have been carried out in2016 to improve the ion source and Linac3 performance,with the goal to increase the beam current routinely deliv-ered to LEIR. The extraction region of the GTS-LHC ionsource was upgraded with enlarged vacuum chamber aper-tures and the addition of an einzel lens, yielding highertransmission through the rest of the machine. Also, a seriesof experiments have been performed to study the effects ofdouble frequency mixing on the afterglow performance ofthe source after installation of a Travelling Wave Tube Am-plifier (TWTA) as secondary microwave source at variablefrequency. Measurements have been carried out at a dedi-cated oven test stand for better understanding of the ionsource performance. Finally, several MD sessions werededicated to the study and characterization of the strippingfoils, after evidence of degradation in time was discoveredin the 2015 run.

LFSC - Linac Feedback Simulation Code

Energy Technology Data Exchange (ETDEWEB)

Ivanov, Valentin; /Fermilab

2008-05-01

The computer program LFSC (<Linac Feedback Simulation Code>) is a numerical tool for simulation beam based feedback in high performance linacs. The code LFSC is based on the earlier version developed by a collective of authors at SLAC (L.Hendrickson, R. McEwen, T. Himel, H. Shoaee, S. Shah, P. Emma, P. Schultz) during 1990-2005. That code was successively used in simulation of SLC, TESLA, CLIC and NLC projects. It can simulate as pulse-to-pulse feedback on timescale corresponding to 5-100 Hz, as slower feedbacks, operating in the 0.1-1 Hz range in the Main Linac and Beam Delivery System. The code LFSC is running under Matlab for MS Windows operating system. It contains about 30,000 lines of source code in more than 260 subroutines. The code uses the LIAR ('Linear Accelerator Research code') for particle tracking under ground motion and technical noise perturbations. It uses the Guinea Pig code to simulate the luminosity performance. A set of input files includes the lattice description (XSIF format), and plane text files with numerical parameters, wake fields, ground motion data etc. The Matlab environment provides a flexible system for graphical output.

Analysis of an induction linac driver system for inertial fusion

International Nuclear Information System (INIS)

Hovingh, J.; Brady, V.O.; Faltens, A.; Keefe, D.; Lee, E.P.

1987-07-01

A linear induction accelerator that produces a beam of energetic (5 to 20 GeV) heavy (130 to 210 amu) ions is a prime candidate as a driver for inertial fusion. Continuing developments in sources for ions with charge state greater than unity allow a potentially large reduction in the driver cost and an increase in the driver efficiency. The use of high undepressed tunes (σ 0 ≅ 85 0 ) and low depressed tunes (σ ≅ 8.5 0 ) also contributes to a potentially large reduction in the driver cost. The efficiency and cost of the induction linac system are discussed as a function of output energy and pulse repetition frequency for several ion masses and charge states. The cost optimization code LIACEP, including accelerating module alternatives, transport modules, and scaling laws, is presented. Items with large cost-leverage are identified as a guide to future research activities and development of technology that can yield substantial reductions in the accelerator system cost and improvement in the accelerator system efficiency. Finally, a cost-effective strategy using heavy ion induction linacs in a development scenario for inertial fusion is presented. 34 refs., 6 figs., 7 tabs

Matter-wave solitons supported by quadrupole-quadrupole interactions and anisotropic discrete lattices

Science.gov (United States)

Zhong, Rong-Xuan; Huang, Nan; Li, Huang-Wu; He, He-Xiang; Lü, Jian-Tao; Huang, Chun-Qing; Chen, Zhao-Pin

2018-04-01

We numerically and analytically investigate the formations and features of two-dimensional discrete Bose-Einstein condensate solitons, which are constructed by quadrupole-quadrupole interactional particles trapped in the tunable anisotropic discrete optical lattices. The square optical lattices in the model can be formed by two pairs of interfering plane waves with different intensities. Two hopping rates of the particles in the orthogonal directions are different, which gives rise to a linear anisotropic system. We find that if all of the pairs of dipole and anti-dipole are perpendicular to the lattice panel and the line connecting the dipole and anti-dipole which compose the quadrupole is parallel to horizontal direction, both the linear anisotropy and the nonlocal nonlinear one can strongly influence the formations of the solitons. There exist three patterns of stable solitons, namely horizontal elongation quasi-one-dimensional discrete solitons, disk-shape isotropic pattern solitons and vertical elongation quasi-continuous solitons. We systematically demonstrate the relationships of chemical potential, size and shape of the soliton with its total norm and vertical hopping rate and analytically reveal the linear dispersion relation for quasi-one-dimensional discrete solitons.

The effect of Berberine preparation on diarrheal symptoms due to Linac irradiation

International Nuclear Information System (INIS)

Hiasa, Tsuyoshi; Mitao, Satoshi; Tanaka, Motofumi; Matsubayashi, Shigeru; Kato, Koji

1979-01-01

Kyoberine, a preparation made from berberine, was administered in 20 cases of malignant tumors (16 cases of cervical carcinoma, 2 cases of corpus uteri carcinoma, and 2 cases of ovarian carcinoma) in which diarrhea was an acute symptom resulting from Linac irradiation. Diarrhea occurred frequently in the patients who received 1600 - 2000 rad. In regard to the characteristics of the feces, this drug was remarkably effective in 25% of the patients and effective in 65% total effectiveness, 90%. In regard to the frequency of diarrhea, it was remarkably effective in 30% of the patients and effective in 60% total effectiveness, 90%. A comprehensive assessment of the effect on the characteristics of the feces and the frequency of diarrhea revealed the drug to be remarkably effective in 7 cases (35%) and effective in 11 (55%). After serial administration of the drug, recurrence of diarrhea was noted only in one case out of 18 in which the drug was effective. Examinations of body weight, peripheral blood, the liver, the kidneys, and electrolytes revealed no side effects. This drug had an excellent effect on diarrhea due to Linac irradiation. Because of its depressant action on peristaltic reflexes and its anti-inflammatory and anti-ulcerative actions, it is hoped that it can be used to prevent radiation injuries. (Ueda, J.)

BARC-TIFR Pelletron Linac facility

International Nuclear Information System (INIS)

Gore, J.A.; Gupta, A.K.; Saxena, A.

2017-01-01

The Pelletron Accelerator, set up as a collaborative project between the Bhabha Atomic Research Centre and the Tata Institute of Fundamental Research, has been serving as the workhorse for the heavy ion accelerator based research in India since its commissioning in December 30, 1988. The facility was augmented with an indigenously developed superconducting Linac booster to enhance the energy of the Pelletron accelerated beams and was fully commissioned on November 28, 2007. The augmented facility is renamed as Pelletron Linac facility (PLF). While the PLF is predominantly utilized by the experimental users from BARC and TIFR, the users include researchers from other research institutions and universities within India and abroad

Transverse Matching Progress Of The SNS Superconducting Linac

International Nuclear Information System (INIS)

Zhang, Yan; Cousineau, Sarah M.; Liu, Yun

2011-01-01

Experience using laser-wire beam profile measurement to perform transverse beam matching in the SNS superconducting linac is discussed. As the SNS beam power is ramped up to 1 MW, transverse beam matching becomes a concern to control beam loss and residual activation in the linac. In our experiments, however, beam loss is not very sensitive to the matching condition. In addition, we have encountered difficulties in performing a satisfactory transverse matching with the envelope model currently available in the XAL software framework. Offline data analysis from multi-particle tracking simulation shows that the accuracy of the current online model may not be sufficient for modeling the SC linac.

Argonne tandem as injector to a superconducting linac

International Nuclear Information System (INIS)

Yntema, J.L.; Den Hartog, P.K.; Henning, W.; Kutschera, W.

1980-01-01

The Argonne Tandem uses Pelletron chains, NEC accelerator tubes, and a dual closed-corona system. Its main function is to be an injector for a superconducting linear accelerator. As long as the transverse and longitudinal emittances are within the acceptance of the linac, the output beam quality of the tandem-linac system is essentially determined by the tandem. The sensitivity of the linac to the longitudinal emittance ΔEΔt of the incident beam makes the output beam quality dependent on the negative-ion velocity distribution in the source, transit-time effects in the tandem, molecular-beam dissociation, and stripper-foil uniformity. This paper discusses these beam-degrading effects

All systems go for LHC quadrupoles

CERN Multimedia

2003-01-01

The series fabrication of the Main Quadrupole cold masses for the LHC has begun with the delivery of the first unit on February 12th. The superconducting dipole magnets required to bend the proton beams around the LHC are often in the news. Less famous, perhaps, but equally important are the 360 main quadrupole (MQ) magnets, which will perform the principal focusing around the 27 km ring. CERN and CEA-Saclay began collaborating on the development and prototyping of these magnets in 1989. This resulted in five highly successful quadrupole units - also known as short straight sections - one of which was integrated for testing in String 1, and two others of the final design in String 2. Once the tests had confirmed the validity of the design and realization, the fabrication of the 360 cold masses had to be transferred to industry. After highly competitive tendering, the German firm ACCEL Instruments was entrusted both with the construction of the quadrupole magnets themselves, and with their assembly into the co...

Nonuniform radiation damage in permanent magnet quadrupoles.

Science.gov (United States)

Danly, C R; Merrill, F E; Barlow, D; Mariam, F G

2014-08-01

We present data that indicate nonuniform magnetization loss due to radiation damage in neodymium-iron-boron Halbach-style permanent magnet quadrupoles. The proton radiography (pRad) facility at Los Alamos uses permanent-magnet quadrupoles for magnifying lenses, and a system recently commissioned at GSI-Darmsdadt uses permanent magnets for its primary lenses. Large fluences of spallation neutrons can be produced in close proximity to these magnets when the proton beam is, intentionally or unintentionally, directed into the tungsten beam collimators; imaging experiments at LANL's pRad have shown image degradation with these magnetic lenses at proton beam doses lower than those expected to cause damage through radiation-induced reduction of the quadrupole strength alone. We have observed preferential degradation in portions of the permanent magnet quadrupole where the field intensity is highest, resulting in increased high-order multipole components.

Nonuniform radiation damage in permanent magnet quadrupoles

International Nuclear Information System (INIS)

Danly, C. R.; Merrill, F. E.; Barlow, D.; Mariam, F. G.

2014-01-01

We present data that indicate nonuniform magnetization loss due to radiation damage in neodymium-iron-boron Halbach-style permanent magnet quadrupoles. The proton radiography (pRad) facility at Los Alamos uses permanent-magnet quadrupoles for magnifying lenses, and a system recently commissioned at GSI-Darmsdadt uses permanent magnets for its primary lenses. Large fluences of spallation neutrons can be produced in close proximity to these magnets when the proton beam is, intentionally or unintentionally, directed into the tungsten beam collimators; imaging experiments at LANL’s pRad have shown image degradation with these magnetic lenses at proton beam doses lower than those expected to cause damage through radiation-induced reduction of the quadrupole strength alone. We have observed preferential degradation in portions of the permanent magnet quadrupole where the field intensity is highest, resulting in increased high-order multipole components

Nonuniform radiation damage in permanent magnet quadrupoles

Energy Technology Data Exchange (ETDEWEB)

Danly, C. R.; Merrill, F. E.; Barlow, D.; Mariam, F. G. [Los Alamos National Laboratory, Los Alamos, New Mexico 87544 (United States)

2014-08-15

We present data that indicate nonuniform magnetization loss due to radiation damage in neodymium-iron-boron Halbach-style permanent magnet quadrupoles. The proton radiography (pRad) facility at Los Alamos uses permanent-magnet quadrupoles for magnifying lenses, and a system recently commissioned at GSI-Darmsdadt uses permanent magnets for its primary lenses. Large fluences of spallation neutrons can be produced in close proximity to these magnets when the proton beam is, intentionally or unintentionally, directed into the tungsten beam collimators; imaging experiments at LANL’s pRad have shown image degradation with these magnetic lenses at proton beam doses lower than those expected to cause damage through radiation-induced reduction of the quadrupole strength alone. We have observed preferential degradation in portions of the permanent magnet quadrupole where the field intensity is highest, resulting in increased high-order multipole components.

History of the JAERI linac facility for 33 years

International Nuclear Information System (INIS)

Ohkubo, Makio; Mizumoto, Motoharu; Nakajima, Yutaka; Mashiko, Katsuo

1994-01-01

The JAERI electron linear accelerator will be shutdown and disassembled at the end of 1993. At the JAERI, a prototype 20 MeV linac was constructed at 1960, and was used for the neutron time-of-flight experiments and for the isotope productions. An upgraded 120 MeV linac was constructed at 1972, and was used for many fields of research works until 1993. History of the JAERI Linac and the results of the works made using these facilities are reviewed, and also R/D on the accelerator engineering are described briefly. (author)

Pulse width modulation based pneumatic frequency tuner of the superconducting resonators at IUAC

International Nuclear Information System (INIS)

Pandey, A.; Suman, S.K.; Mathuria, D.S.

2015-01-01

The existing phase locking scheme of the quarter wave resonators (QWR) used in superconducting linear accelerator (LINAC) of IUAC consists of a fast time (electronic) and a slow time (pneumatic) control. Presently, piezo based mechanical tuners are being used to phase lock the resonators installed in the second and third accelerating modules of LINAC. However, due to space constraint, the piezo tuner can't be implemented on the resonators of the first accelerating module. Therefore, helium gas operated mechanical tuners are being used to phase lock the resonators against the master oscillator (MO) frequency. The present pneumatic frequency tuner has limitations of non-linearity, hysteresis and slow response time. To overcome these problems and to improve the dynamics of the existing tuner, a new pulse width modulation (PWM) based pneumatic frequency tuning system was adopted and successfully tested. After successful test, the PWM based pneumatic frequency tuner was installed in four QWR of the first accelerating module of LINAC. During beam run the PWM based frequency tuner performed well and the cavities could be phase locked at comparatively higher accelerating fields. A comparison of the existing tuning mechanism and the PWM based tuning system along with the test results will be presented in the paper. (author)

Ion-storage in radiofrequency electric quadrupole field

International Nuclear Information System (INIS)

Gheorghe, V.

1976-01-01

The confinement of charged particles in a quadrupole radiofrequency electric field are presented. The stability diagrams and phase space trajectories for the quadrupole mass spectrometer and for the ion trap are represented and their main characteristics are discussed. (author)

Preinjector for Linac 1, accelerating column

CERN Multimedia

1974-01-01

For a description of the Linac 1 preinjector, please see first 7403070X. High up on the wall of the Faraday cage (7403073X) is this drum-shaped container of the ion source (7403083X). It is mounted at the HV end of the accelerating column through which the ions (usually protons; many other types of ions in the course of its long history) proceed through the Faraday cage wall to the low-energy end (at ground potential) of Linac 1. The 520 kV accelerating voltage was supplied by a SAMES generator (7403074X).

Compensated linac beam colliding with a stored beam

International Nuclear Information System (INIS)

Csonka, P.L.; Oregon Univ., Eugene

1981-01-01

The disruptive effect of a linac beam on a beam circulating in a storage ring can be reduced by compensating for the space charge of the linac beam with a beam which is oppositely charged, may have different bunchlength as well as lower energy, and need not be circulating in a storage ring. (orig.)

Properties of heavy ion linacs with alternating phase focusing

International Nuclear Information System (INIS)

Deitinghoff, H.; Junior, P.; Klein, H.

1976-01-01

General aspects for the application of alternating phase focusing are discussed. The results demand necessary linac parameters. The possibility of their accomplishment by already existing or feasible linac structures with acceleration rates of 2 - 3 MV/m will be considered

Beam halo in high-intensity hadron linacs

Energy Technology Data Exchange (ETDEWEB)

Gerigk, F

2006-12-21

This document aims to cover the most relevant mechanisms for the development of beam halo in high-intensity hadron linacs. The introduction outlines the various applications of high-intensity linacs and it will explain why, in the case of the CERN Superconducting Proton Linac (SPL) study a linac was chosen to provide a high-power beam, rather than a different kind of accelerator. The basic equations, needed for the understanding of halo development are derived and employed to study the effects of initial and distributed mismatch on high-current beams. The basic concepts of the particle-core model, envelope modes, parametric resonances, the free-energy approach, and the idea of core-core resonances are introduced and extended to study beams in realistic linac lattices. The approach taken is to study the behavior of beams not only in simplified theoretical focusing structures but to highlight the beam dynamics in realistic accelerators. All effects which are described and derived with simplified analytic models, are tested in realistic lattices and are thus related to observable effects in linear accelerators. This approach involves the use of high-performance particle tracking codes, which are needed to simulate the behavior of the outermost particles in distributions of up to 100 million macro particles. In the end a set of design rules are established and their impact on the design of a typical high-intensity machine, the CERN SPL, is shown. The examples given in this document refer to two different design evolutions of the SPL study: the first conceptual design report (SPL I) and the second conceptual design report (SPL II). (orig.)

submitter Radiation Protection Studies for CERN LINAC4/SPL Accelerator Complex

CERN Document Server

Mauro, Egidio; Silari, Marco

2009-01-01

CERN is presently designing a new chain of accelerators to replace the present Proton Synchrotron (PS) complex: a 160 MeV room-temperature H$^-$ linac (Linac4) to replace the present 50 MeV proton linac injector, a 3.5 GeV Superconducting Proton Linac (SPL) to replace the 1.4 GeV PS booster (PSB) and a 50 GeV synchrotron (named PS2) to replace the 26 GeV PS. Linac4 has been funded and the civil engineering work started in October 2008, whilst the SPL is in an advanced stage of design. Beyond injecting into the future 50 GeV PS, the ultimate goal of the SPL is to generate a 4 MW beam for the production of intense neutrino beams. The radiation protection design is driven by the latter requirement. This thesis summarizes the radiation protection studies conducted for Linac4. FLUKA Monte Carlo simulations, complemented by analytical estimates, were performed 1) to evaluate the propagation of neutrons through the waveguide, ventilation and cable ducts placed along the accelerator, 2) to estimate the radiological i...

Release the beams! - Linac4 ready to hit the 50 MeV mark

CERN Multimedia

Katarina Anthony

2015-01-01

The Linac4 accelerator is now prepared to reach 50 MeV. This milestone energy - expected in the coming weeks - will allow the machine to act as a replacement for the ageing Linac2, four years before it takes over at the head of the accelerator chain in 2020.    Inside the Linac4 tunnel, the final DTL cavities will guide beams to 50 MeV.  (Image: Stephan Russenschuck.) The Linac4 accelerator will bring H- ion beams (hydrogen atoms with an extra electron) up to 160 MeV for injection into the PS Booster. As a key part of the LHC injector upgrade programme, Linac4 will allow the PS Booster to double its beam brightness, which will contribute to increasing the LHC’s luminosity. Linac4 will soon bring beams up to 50 MeV - the current energy delivered by the Linac2 accelerator. This milestone follows on from another recent accomplishment: the installation and commissioning of the final Drift Tube Linac (DTL) tank. Using an innovati...