A thermal analysis model for high power density beam stops

Virostek, S.; Oshatz, D.; Staples, J.

doi:10.1109/pac.2001.986753

Cited by 3 publications

(1 citation statement)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Differential, transverse, thermal expansion would create a Von Mises Stress in the faceplate of 271 MPa, 65 % of the yield strength of TZM, including a derating for temperature and fatigue loading. The reduction of the FES peak current requirement to 38 mA by the SNS collaboration should reduce the peak surface temperature to 106°C and the peak surface stress to 93 MPa [3]. The target assembly is suspended in its vacuum beambox from a stepper motor driven bellows feedthrough and can be vertically adjusted during tuning by increments as small as 0.02 mm.…”

Section: Chopper Targetmentioning

confidence: 99%

Mechanical design of the SNS MEBT

Oshatz

DeMello

Doolittle

et al.

PACS2001. Proceedings of the 2001 Particle Accelerator Conference (Cat. No.01CH37268)

Self Cite

View full text Add to dashboard Cite

The Lawrence Berkeley National Laboratory (LBNL) is presently designing and building the 2.5 MeV front end for the Spallation Neutron Source (SNS). The front end includes a medium-energy beam transport (MEBT) that carries the 2.5 MeV, 38 mA peak current, H -beam from the radio frequency quadrupole (RFQ) to the drift tube linac (DTL) through a series of 14 electromagnetic quadrupoles, four rebuncher cavities, and a fast traveling wave chopping system. The beamline contains numerous diagnostic devices, including stripline beam position and phase monitors (BPM), toroid beam current monitors (BCM), and beam profile monitors. Components are mounted on three rafts that are separately supported and aligned. The large number of beam transport and diagnostic components in the 3.6 meter-long beamline necessitates an unusually compact mechanical design. PHYSICS REQUIREMENTSThe SNS is an accelerator-based user facility that will produce pulsed beams of neutrons for use in scattering experiments. LBNL has designed and is fabricating the Front-End Systems (FES) comprising an ion source, lowenergy beam transport (LEBT) with a pre-chopper, 402.5 MHz RFQ, and MEBT. The FES will accelerate a 38 mA, 6% duty factor, H -ion beam to 2.5 MeV for injection into the 1 GeV linac [1].The MEBT lattice matches the beam from the RFQ through two fast traveling wave choppers into the first tank of the DTL. The 35-cm long choppers perform the final beam chopping that prevents beam from intercepting the septum of the extraction kicker magnet in the accumulator ring during its rise time. A closely spaced lattice with strong focusing is required to minimize emittance growth, due to the nonlinear charge distribution of the beam and the 62-cm drifts required for insertion of the choppers [2]. The layout of the beamline has been optimized to minimize emittance growth while taking into consideration the mechanical implications of closely spaced transport components and diagnostic devices.The MEBT lattice consists of fourteen quadrupole magnets, four rebuncher cavities, two traveling-wave choppers, and a chopper target that intercepts the deflected beam (see Figure 1). Four quadrupoles, one rebuncher, and one chopper are mounted on the first and third rafts, with the remainder of the components arranged symmetrically on the second raft. Six quadrupoles, the first and last magnets on each raft, incorporate dipole steering to correct for misalignments between rafts. Diagnostic devices located between transport components monitor beam quality during operation and enable tuning of the MEBT itself. TRANSPORT COMPONENTSPhysically compact devices have been devised, with careful consideration for mounting and alignment features in order to accomplish the positional accuracy and tight longitudinal spacing necessitated by the goal of minimal emittance growth. Quadrupole MagnetsThe physical envelope of the quadrupoles was tightly constrained by the available longitudinal space and the fit with the beam position monitors (BPM) and beampipes that it surrou...

show abstract

Section: Chopper Targetmentioning

confidence: 99%

Mechanical design of the SNS MEBT

Oshatz

DeMello

Doolittle

et al.

PACS2001. Proceedings of the 2001 Particle Accelerator Conference (Cat. No.01CH37268)

Self Cite

View full text Add to dashboard Cite

show abstract

The Spallation Neutron Source accelerator system design

Henderson¹,

Abraham²,

Aleksandrov³

et al. 2014

Nuclear Instruments and Methods in Physics Research Section A:

108

View full text Add to dashboard Cite

Design and Testing of a Prototype Beam Absorber for the PXIE MEBT

Baffes¹

2014

View full text Add to dashboard Cite

One of the goals of the PXIE program at Fermilab [1] is to demonstrate the capability to form an arbitrary bunch pattern from an initially CW 162.5 MHz H-bunch train coming out of an RFQ. The bunch-by-bunch selection will take place in the 2.1 MeV Medium Energy Beam Transport (MEBT) [2] by directing the undesired bunches onto an absorber that needs to withstand a beam power of up to 21 kW, focused onto a spot with a ~2 mm rms radius. A prototype of the absorber was manufactured from molybdenum alloy TZM, and tested with an electron beam up to the peak surface power density required for PXIE, 17W/mm 2 . Temperatures and flow parameters were measured and compared to analysis. This paper describes the absorber prototype and key testing results.

show abstract

A thermal analysis model for high power density beam stops

Cited by 3 publications

References 6 publications

Mechanical design of the SNS MEBT

Mechanical design of the SNS MEBT

The Spallation Neutron Source accelerator system design

Design and Testing of a Prototype Beam Absorber for the PXIE MEBT

Contact Info

Product

Resources

About