Crystal-based pair production for a lepton collider positron source
L. Bandiera, L. Bomben, R. Camattari, G. Cavoto, I. Chaikovska, R. Chehab, D. De Salvador, V. Guidi, V. Haurylavets, E. Lutsenko, V. Mascagna, A. Mazzolari, M. … 展开作者
L. Bandiera, L. Bomben, R. Camattari, G. Cavoto, I. Chaikovska, R. Chehab, D. De Salvador, V. Guidi, V. Haurylavets, E. Lutsenko, V. Mascagna, A. Mazzolari, M. Prest, M. Romagnoni, F. Ronchetti, F. Sgarbossa, M. Soldani, A. Sytov, M. Tamisari, V. Tikhomirov, E. Vallazza
An intense positron sources is a demanding element in the design of future lepton colliders. A crystal-based hybrid positron source could be an alternative to a more conventional scheme based on the electron conversion into positron in a thick amorphous target. The conceptual idea of the hybrid source is to have two separate objects, a photon radiator and a photon-to-positron converter target. In such a scheme an electron beam crosses a thin axially oriented crystal with the emission of a channeling radiation, characterized by a considerably larger amount of photons if compared to Bremsstrahlung. The net result is an increase in the number of produced positrons at the converter target. In this paper we present the results of a beam test conducted at the DESY TB 21 with 5.6 GeV electron beam and a crystalline tungsten radiator. Experimental data clearly highlight an increased production of photons and they are critically compared with the outcomes of novel method to simulate the number of radiated photons, showing a very good agreement. Strong of this, the developed simulation tool has been exploited to design a simple scheme for a positron source based on oriented crystal, demonstrating the advantages in terms of reduction of both deposited energy and the peak energy deposition density if compared to conventional sources. The presented work opens the way for a realistic and detailed design of a hybrid crystal-based positron source for future lepton colliders.
Positron sources are the key elements for the future and current lepton collider projects such as ILC, CLIC, SuperKEKB, FCC-ee, Muon Collider/LEMMA, etc., introducing challenging critical requirements for high intensity and low emittance beams in order to achieve high luminosity. In fact, due to their large production emittance and constraints given by the target thermal load, the main collider parameters such as the peak and average current, the emittances, the damping time, the repetition frequency and consequently the luminosity are determined by the positron beam characteristics. In this p…
An unprecedented positron average current is required to fit the luminosity demands of future $e^+e^-$ high energy physics colliders. In addition, in order to access precision-frontier physics, these machines require positron polarization to enable exploring the polarization dependence in many HEP processes cross sections, reducing backgrounds and extending the reach of chiral physics studies beyond the standard model. The ILC has a mature plan for the polarized positron source based on conversion in a thin target of circularly polarized gammas generated by passing the main high energy e-beam …
We examine through numerical calculation the collision of counter-propagating trains of optically spaced electron/positron microbunches in a 1 TeV collider scenario for a dielectric laser accelerator (DLA). A time-dependent envelope equation is derived for arbitrary number of bunches in the classical limit, with inclusion of the radiation reaction force (RRF). Example parameters are examined based on a constrained luminosity relation that takes into account the bunch charge for optimal efficiency, material damage limits, and power constraints. We find that for initially identical counter-propa…
Very Asymmetric Collider for Dark Matter Search below 1 GeV
目前对质量范围在1 GeV以下的暗光子的搜索需要一个亮度至少为$10^{34}$ cm $^{-2}$ s $^{-1}$的电子-正电子对撞机。挑战在于，在如此低的能量下，对撞机的亮度由于光束尺寸的增加、碰撞光束的强烈相互聚焦以及集体效应的增强而迅速下降。利用加速器技术的最新进展，如超级KEK-B的纳米束方案，高电流能量回收直线加速器（ERL）和磁化束，我们提出了一种新的配置的电子-正电子对撞机的基础上的正电子存储环和电子ERL。它允许在动量能量小于1 GeV的中心处获得$>10^{34}$ cm $^{-2}$ s $^{-1}$的光度。我们提出了一般的考虑和这样的设施使用的参数SuperKEK-B正电子储存环和康奈尔ERL项目的一个具体例子。
This project proposes to reuse the DAFNE accelerator complex for producing a high intensity (up to 10^10), high-quality beam of high-energy (up to 500 MeV) positrons for HEP experiments, mainly - but not only - motivated by light dark particles searches. Such a facility would provide a unique source of ultra-relativistic, narrow-band and low-emittance positrons, with a high duty factor, without employing a cold technology, that would be an ideal facility for exploring the existence of light dark matter particles, produced in positron-on-target annihilations into a photon+missing mass, and usin…
Accelerator-based searches for dark matter are aiming for high sensitivity and need an experimental setup with high luminosity. This field of research is often called intensity frontier physics. One of the best motivated portals of interaction between dark matter and ordinary matter is a dark photon which could be observed as a resonance in the invariant mass of the decay products. Electron-positron collisions are known to be the cleanest interaction for such a study. In this paper we propose a scheme for a collider which allows for a luminosity of a few orders of magnitude higher than could b…
Advanced acceleration methods based on wakefields generated by high energy electron bunches passing through dielectric-based structures have demonstrated $>$GV/m fields, paving the first steps on a path to applications such as future compact linear colliders. For a collider scenario, it is desirable that, in contrast to plasmas, wakefields in dielectrics do not behave differently for positron and electron bunches. In this Letter, we present measurements of large amplitude fields excited by positron bunches with collider-relevant parameters (energy 20 GeV, and $0.7 \times 10^{10}$ particles per…
Photon collimator system for the ILC Positron Source
高能电子直线对撞机是粒子物理学的下一个大规模项目.它们需要强光源来达到所需的亮度。具体地，正电子源必须每秒提供约10 E +14个正电子。国际直线对撞机（ILC）的正电子源是基于一个螺旋波荡器，电子束通过该波荡器产生一个强圆偏振光子束。利用这些光子，产生纵向偏振的正电子束;偏振度可以通过准直光子束来增强。然而，高光子束强度在准直器材料中引起巨大的热负荷。本文讨论了光子准直器的热负荷问题，并提出了一种灵活的设计方案。
In this paper, the feasibility of the electron-positron collider based on plasma accelerator is proved by simulation experiments. Starting from the 17.612cm proton beam provided by SPS (super proton synchrotron), the simulation shows that the long proton beam can form several high quality proton bunches through seeded self-modulation in the first half of the long proton beam in a uniform plasma. Then we use these high-quality bunches to excite the wakefield in a uniform plasma and accelerate witness positrons and witness electrons. The simulation results show that the average energy of witness…
Beam diagnostics is important to guarantee good quality of beam in particle accelerator. Both the electron and positron run in the tunnel in some modern electron positron colliders such as Circular Electron Positron Collider (CEPC) to be built and Beijing Electron Positron Collider II (BEPC II). To measure the electron and positron beams, picking up of these two different bunches in real time is of notable concern. Because the time interval between adjacent electron and positron bunches is quite small, for example, 6 ns in CEPC, high-speed switch electronics is required. This paper presents th…
The design of a future multi-TeV muon collider needs new ideas to overcome the technological challenges related to muon production, cooling, accumulation and acceleration. In this paper a layout of a positron driven muon source known as the Low EMittance Muon Accelerator (LEMMA) concept is presented. The positron beam, stored in a ring with high energy acceptance and low emittance, is extracted and driven to a multi-target system, to produce muon pairs at threshold. This solution alleviates the issues related to the power deposited and the integrated Peak Energy Density Deposition (PEDD) on th…
We present a Circular Energy Recovery Collider (CERC) as an alternative approach for a high-energy high-luminosity electron-positron collider to current designs for high-energy electron-positron colliders either based on two storage rings with 100 km circumference or two large linear accelerators. Using Energy Recovery Linacs (ERL) located in the same-size 100 km tunnel would allow a large reduction of the beam energy losses, and therefore a reduction of the power consumption, while providing higher luminosity. It also opens a path for extending the center-of-mass (CM) energy to 500 GeV, which…
First of all, an importance of the LHC and FCC based energy frontier lepton-hadron and photon-hadron colliders is emphasised. Then arguments favoring existence of new heavy isosinglet down-type quarks and vector-like isosinglet or isodoublet leptons are presented, following by historical arguments favoring new (preonic) level of matter. The importance of Super-Charm factory and GeV energy proton linac for Turkey national road map is argued. Finally, several recommendations for ESPP2020 are suggested.
