Design of a cw, low-energy, high-power superconducting linac for environmental applications

Abstract

The treatment of flue gases from power plants and municipal or industrial wastewater using electron beam irradiation technology has been successfully demonstrated in small-scale pilot plants. The beam energy requirement is rather modest, on the order of a few MeV, however the adoption of the technology at an industrial scale requires the availability of high beam power, of the order of 1 MW, in a cost effective way. In this article we present the design of a compact superconducting accelerator capable of delivering a cw electron beam with a current of 1 A and an energy of 1 MeV. The main components are an rf-gridded thermionic gun and a conduction cooled β = 0.5 elliptical Nb3Sn cavity with dual coaxial power couplers. An engineering and cost analysis shows that the proposed design would result in a processing cost competitive with alternative treatment methods. List of acronyms SRF -radio-frequency superconductivity GM -Gifford-McMahon BLA -beamline absorber HOM -higher-order mode FPC -fundamental power coupler BBU -beam breakup YBCO -yttrium barium copper oxide CW -continuous wave VED -vacuum electron device

Multi-metallic conduction cooled superconducting radio-frequency cavity with high thermal stability

“…If such dependence would have continued, without the occurrence of a Q-switch, a P loss = 5 W would have been reached at B p = 41 mT. Such value of B p would have met the requirement for a single-cell cavity designed for a 1 MeV electron linear accelerator for environmental remediation [10]. The origin, size and location of the defective regions are unclear at this stage.…”

“…Such improvements in both cryocooler and Nb 3 Sn SRF cavities may enable the design of compact, low-energy (1 − 25 MeV) electron accelerators for industrial and medical applications or for compact light sources [8,9]. An example of such industrial applications is the environmental remediation of flue gases and/or wastewater [10]. Recent work on the development of SRF cavities conduction cooled by a cryocooler has resulted in a 650 MHz single-cell elliptical cavity made of bulk Nb operating up to an accelerating gradient of 1.5 MV/m [11], corresponding to a peak surface magnetic field, B p , of 5.5 mT [12].…”

Перспективные Технологии Для Прикладных Резонансных Ускорителей Заряженных Частиц И Примеры Их Использования (Обзор)

“…Кроме того, содержание и обслуживание этих систем требуют особой квалификации и внимания персонала, поскольку при такой нештатной ситуации как квенч [323], размораживание или механическое повреждение, сверхпроводящий ускоритель или его часть может навсегда выйти из строя [324,325]. Развитие технологий в области сверхпроводимости, произошедшее за последнее десятилетие, позволяют значительно упростить дизайн сверхпроводящих ускорителей, а также сделать их мобильными, энергетически и экономически эффективными при мощности пучка порядка 1 MW [326], чего невозможно достичь с помощью нормальнопроводящих установок. Из таких технологий можно выделить следующие: усовершенствование формы резонаторов [327], процесса их производства [328] и обработки поверхности, в частности, инфузии атомами азота [329], а также применения техник быстрого охлаждения для избежания так называемой Q-болезни [330,331], позволили достичь значений собственных добротностей до 10 11 [332] при работе на ускоряющих градиентах до 20 MV/m [333,334].…”

Nitrogen doping and infusion in SRF cavities: A review

“…In addition to Nb cavities, the alternative materials Nb3Sn are being explored in order to achieve high quality factor, however so far the accelerating gradient are limited to below 20 MV/m [157,158,159]. Thin Nb3Sn cavities are fabricated using thermal diffusion of Sn on Nb cavities, potential for industrial applications [160]. For high accelerating gradient cavities, multilayers of superconducting are being considered [161,162].…”