Superconducting technology makes it possible to build a high energy \(e^+e^-\) linear collider with energy recovery (ERLC) and reusable beams. To avoid parasitic collisions inside the linacs, a twin ...(dual) LC is proposed. In this article, I consider the principle scheme of the collider and estimate the achievable luminosity, which is limited by collision effects and available power. Such a collider can operate in a duty cycle (DC) and in a continuous (CW) modes, if sufficient power. With current SC Nb technology (\(T=1.8\) K, \(f_{\rm RF}=1.3\) GHz, used for ILC) and with power \(P= 100\) MW, a luminosity \(L \sim 0.33 \times10^{36}\,\rm cm^{-2}s^{-1}\) is possible at the Higgs factory with \(2E_0=250\) GeV. Using superconductors operating at 4.5 K with high \(Q_0\) values, such as Nb\(_3\)Sn, and \(f_{\rm RF}=0.65\) GHz, the luminosity can reach \(L \sim 1.4 \times10^{36} \,\rm cm^{-2}s^{-1}\) at \(2E_0=250\) GeV (with P=100 MW) and \(L \sim 0.8 \times 10^{36}\,\rm cm^{-2}s^{-1}\) at \(2E_0=500\) GeV (with P=150 MW), which is almost two orders of magnitude greater than at the ILC, where the beams are used only once. This technology requires additional efforts to obtain the required parameters and reliably operation. Such a collider would be the best machine for precision Higgs studies, including the measurement of Higgs self-coupling.
We report results of a search for narrow resonances in e super(+e) super(-) annihilation at center-of-mass energies between 1.85 and 3.1 GeV performed with the KEDR detector at the VEPP-4M e ...super(+e) super(-) collider. The upper limit on the leptonic width of a narrow resonance inline image has been obtained (at 90% C.L.).
Recently, a high energy superconducting (SC) \epem linear collider (LC) with energy recovery (ERLC) have been proposed where twin RF structures are used to avoid parasitic collisions within linacs. ...Such a collider can operate in a duty cycle (DC) or in a continuous (CW) modes (if sufficient power) with a luminosity of \({\cal O}(10^{36})\) \cms at \(2E_0=250-500\) GeV. In this paper, I note that the luminosity at the ERLC operating in duty cycle mode does not depend on the accelerating gradient (at the same total power), but only slightly changes as \(L \propto \sqrt{Q}\). So, the ERLC can work at maximum available acceleration gradients. The article also considers \(e^-e^-\) twin collider with energy recovery and estimates the achievable luminosity. Such an \(e^-e^-\) collider is much simpler than \(e^+e^-\) one, because beam recirculation is not required, can have \(L\) well above \(10^{36}\) cm\(^{-2}\)s\(^{-1}\). It also has a fairly rich physics program.
The discovery of the Higgs boson (and still nothing else) have triggered appearance of many proposals of Higgs factories for precision measurement of the Higgs properties. Among them there are ...several projects of photon colliders (PC) without e+e- in addition to PLC based on e+e- linear colliders ILC and CLIC. In this paper, following a brief discussion of Higgs factories physics program I give an overview of photon colliders based on linear colliders ILC and CLIC, and of the recently proposed photon-collider Higgs factories with no e+e- collision option based on recirculation linacs in ring tunnels.
Calibration of the absolute energy scale at high-energy photon (gamma-gamma, gamma-electron) colliders is discussed. The luminosity spectrum at photon colliders is broad and has a rather sharp ...high-energy edge, which can be used, for example, to measure the mass of the Higgs boson in the process gamma-gamma to H or masses of charged scalars by observing the cross-section threshold. In addition to the precise knowledge of the edge energy of the luminosity spectrum, it is even more important to have a way to calibrate the absolute energy scale of the detector. At first sight, Compton scattering itself provides a unique way to determine the beam energies and produce particles of known energies that could be used for detector calibration. The energy scale is given by the electron mass m_e and laser photon energy \omega_0. However, this does not work at realistic photon colliders due to large nonlinear effects in Compton scattering at the conversion region (\xi^2 \sim 0.3). It is argued that the process gamma-electron to eZ_0 provides the best way to calibrate the energy scale of the detector, where the energy scale is given by m_Z.
In this paper we consider two types of gaseous detectors for radiography. The first one, the Multiwire Proportional Chamber, is used at present as a part of the digital radiographic system. It works ...in counting mode, has a quantum efficiency of 30% and a spatial resolution of 0.6mm. Our new detector, the Multistrip Ionisation Chamber, is filled with Xe at 10atm., has a quantum efficiency up to 70% and a spatial resolution of 0.4mm. This method with integration of collected charge allows to avoid the problems of counting rate and gas ageing and considerably reduces the cost of electronics.
The objective of the study is the assessment of lifetime in the cohort of Mayak PA workers employed in 1948-1958 and exposed to incorporated Pu-239. The decrease of age at death 5.2 years among males ...and 6.6 years among females, and after the start of work--6.9 years among males and 7.7 years among females, with the increase of Pu-239 incorporation was shown. The association of the raised mortality rate from tumour causes is shown both among males and females, mainly due to malignant neoplasms of lung and live; which are organs of Pu-239 main deposition. For the first time related to Pu-239 incorporation decrease of age at death from tumour and non-tumour causes of main and secondary organs of deposition both among males and females was revealed. To assess the reduction of lifetime Years of Potential Life Lost (YPLL) were calculated per 10(5) person-years of potential life based on European gender standard. The calculations based on the obtained estimations showed significant dependence of YPLL on the level of Pu-239 incorporation. At that the main contribution to the increase of YPLL, i.e. to lifetime reduction, was due to radiation-induced decrease of the age at death as compared to radiation-induced increase of mortality rates.
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