Start-to-end Beam Optics Development and Multi-particle Tracking for the ILC Positron Source

Zhou, Feng; Nosochkov, Y.; Sheppard, J.C.; Woodley,

doi:10.2172/898144

Cited by 7 publications

(6 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The ELEGANT code positron beam within the 6-dimensional acceptance in the DR equal to γ(A x +A y ) <0.09 m and (±25 MeV)×(±3.46 cm). Of the positrons from the target, 55% survive the transport through the complete beamline based on the physical apertures of the beam pipes [21] and ∼50% of the positrons are within the DR 6-dimensional acceptance. An energy collimator in the LTR second arc reduces the number of unwanted particles reaching the DR from 5.6% to 1.1%.…”

Section: Beam Transportmentioning

confidence: 99%

International linear collider reference design report

Aarons¹

2007

View full text Add to dashboard Cite

Section: Beam Transportmentioning

confidence: 99%

International linear collider reference design report

Aarons¹

2007

View full text Add to dashboard Cite

“…Argonne Laboratory also began modeling of positron conversion with undulator using EGS4, Geant4 and Fluka [19]. Same type of calculations carried at SLAC [28] Answer to this question obtained is that K<0.4, u λ =1cm, L~175 is enough for 1:1.5 conversion in positrons with ~60% polarization for collection with Lithium lens (see below). Bigger K~0.9 allows having L~30m with polarization ~40%.…”

Section: Simulation Of Conversion Diagram Onmentioning

confidence: 99%

ILC undulator based positron source, tests and simulations

Mikhailichenko

2007

2007 IEEE Particle Accelerator Conference (PAC)

View full text Add to dashboard Cite

Abstract. An undulator based positron source allows generation of polarized positrons in quantities required by ILC. Here we describe the results of modeling and testing of elements for such a system. Classification 3: Linear Colliders, Lepton Accelerators and New Acceleration Techniques, A03. Work supported by NSF grant PHY-0202078 INTRODUCTIONThe scheme for polarized positron production was proposed a long time ago in a framework of VLEPP project [1]. The basis of the method is a two stage process, where at first stage the circularly polarized photons generated in helical electromagnetic field and then, at second stage, these photons converted into positrons and/or electrons in a thin (~half radiation length) target. Secondary particles carry longitudinal polarization transferred from the primary photon beam in accordance with theirs energy. In this first publication [1] the gammas considered to be generated by energetic particle in the following substances: in a field of electromagnetic wave, in static magnetic helical field of undulator and in crystals with helical dislocations (helical crystals). In [2] the laser radiation was considered as a specific example of an electromagnetic wave. With application of selection of energetic positrons only, the final polarization increased and defined by the length of undulator (as one needs to compensate partial collection of secondary positrons). For typical length of undulator~175 m, the degree of polarization reaches 60% and it could reach 85% with 300 m long undulator. One peculiarity associated with helical undulator scheme is that this system is able to generate polarized positrons with degree of polarization ~30% if no energy selection mechanism applied to the positrons at all. The undulator scheme of positron production has been chosen as a baseline for ILC [3] accommodated from TESLA design [4]. One peculiarity here is that the beam, like in original VLEPP scheme is going through the undulator on its way to IP. One positive moment of this is that the beam can be made having small transverse dimensions as the emittance is small. This allows small aperture in undulator and hence makes engineering problem less severe. From the other hand nonlinear field of undulator could disturb this tiny emittance and polarization of this primary beam while it is going to IP. Considerations show that this is not a problem here however as the beam trajectory remains line-type with accuracy ~1/ γ so the nonlinearities cancel each other. So the ILC scheme looks as it is represented in Fig.1

show abstract

“…Argonne Laboratory also began modeling of positron conversion with undulator using EGS4, Geant4 and Fluka [19]. Same type of calculations carried at SLAC [28] Answer to this question obtained is that K<0.4, u ! =1cm, L~175 is enough for 1:1.5 conversion in positrons with ~60% polarization.…”

Section: Diagram Onmentioning

confidence: 99%

Final Report DE-FG02-041353

Dugan¹,

Tigner²

2007

View full text Add to dashboard Cite

There were two major objectives of the work supported by this grant: 1) tests of a high voltage pulser for the ILC damping ring kickers; 2) ILC undulator based positron source tests and simulations.Damping Ring Kicker Pulser (04-05, 05-06) The ILC damping rings require kickers able to inject and extract bunches of approximately 3 ns spacing without disturbing neighboring bunches. In addition, the kickers must be able to operate in 3.25 MHz bursts with an average pulse rate of 14.1 kHz, driven by 10 kV pulsers. The work reported here focused on the pulser itself. Bench and beam tests of a commercial pulser built by FID Technology were carried out. The pulser, model FPG2-3000-MC2 has a nominal output of + and -1 kV with advertised rise and fall times and rep rate capability close to that needed by the ILC. Details of the specification derivation and the pulser tests can be found in the appended paper (THPCH148) which was published in the proceedings of EPAC2006, Figure 1 shows waveforms of the positive and negative 1.08 kV outputs measured with an oscilloscope Fig. 1 Waveform obtained from the FPG2-3000-MC2 pulser with 46 db attenuation. The waveform shown is for the first pulse in a burst and is the accumulation of several hundred sweeps, 1 ns per horizontal square.If we define the full width of the pulse to be the period between the 10% points we see that the pulse is about 5 ns, somewhat wider than desirable for use with bunch spacing of 3 ns and 1 ns long stripline kicker. A large portion of this width is due to the approximately 2.4 ns fall-time of the pulse. Since this will only impact the trailing "hot" bunch, it may be acceptable. A variation of 2% in amplitude over the pulses measured was recorded.As a further test of the performance of the pulser under accelerator operating conditions, it was used to drive an existing 2.1 ns long stripline kicker on the A0 photo-injector beamline at Fermilab. The kick delivered to a nominal 15 MeV beam was measured and simulated using a digitized recording of the waveforms above. The measured result is shown in Fig. 2 and agrees well with the simulation.While the measured parameters of the pulser approach that required by the ILC, issues remain: a unit operating at 10 kV must be demonstrated; amplitude stability must be improved by a factor of 2; a detailed characterization of the pulses throughout the train is required. Fig. 2 Beam kick obtained by scanning the pulser trigger relative to the beam arrival time taken at the A0 photo-injector.ILC Undulator Based Positron Source (06-07) After due consideration of positron sources based on electrons on a heavy metal target, inverse Compton effect, and high energy gamma rays on a relatively thin heavy metal target, the ILC Reference Design selected the undulator source as the baseline. Considerations of efficiency, and the possibility of creating polarized positrons, led to the choice of a superconducting, helical undulator approach.In the work supported by this grant, a design for modules comprising the full scale undulator ...

show abstract

Start-to-end Beam Optics Development and Multi-particle Tracking for the ILC Positron Source

Cited by 7 publications

References 2 publications

International linear collider reference design report

International linear collider reference design report

ILC undulator based positron source, tests and simulations

Final Report DE-FG02-041353

Contact Info

Product

Resources

About