IsoDAR is a novel experiment designed to measure neutrino oscillations through $\barν_e$ disappearance, thus providing a definitive search for sterile neutrinos. In order to generate the necessary anti-neutrino flux, a high intensity primary proton beam is needed. In IsoDAR, $\mathrm{H}_2^+$ is accelerated and is stripped into protons just before the target, to overcome space charge issues at injection. As part of the design, we have refined an old proposal to use an RFQ to axially inject bunched $\mathrm{H}_2^+$ ions into the driver cyclotron. This method has several advantages over a classical low energy beam transport (LEBT) design: (1) The bunching efficiency is higher than for the previously considered two-gap buncher and thus the overall injection efficiency is higher. This relaxes the constraints on the $\mathrm{H}_2^+$ current required from the ion source. (2) The overall length of the LEBT can be reduced. (3) The RFQ can also accelerate the ions. This enables the ion source platform high voltage to be reduced from 70 kV to 15 kV, making underground installation easier. We are presenting the preliminary RFQ design parameters and first beam dynamics simulations from the ion source to the spiral inflector entrance.
High current $\mathrm{H}_2^+$ beams from a filament-driven multicusp ion source
最近，使用$\mathrm{H}_2^+$离子代替质子来克服紧凑型回旋加速器中的空间电荷挑战受到了广泛关注。这项技术有可能将紧凑型回旋加速器的可用束流增加一个数量级，为能源研究，医学同位素生产和粒子物理学的应用铺平道路，例如通过IsoDAR实验决定性地寻找无菌中微子。对于IsoDAR，我们不仅仅使用$\mathrm{H}_2^+$，还通过嵌入在回旋加速器轭中的射频四极（Radio Frequency Quadrupole，缩写为QF）添加了预聚束。这对离子源提出了束纯度和束质量限制，迄今为止还没有公开的离子源同时证明了这一点。在这里，我们报告的结果，从一个新的multicusp离子源（MIST-1），产生世界上最高的稳态电流的$\mathrm{H}_2^+$从这种类型的离子源（1毫安），具有极低的发射率（0.05 $π$ -毫米-毫拉德，RMS，归一化）和高纯度（80% $\mathrm{H}_2^+$）。这一结果表明，使用多尖锥离子源的IsoDAR和直接注入原型的可行性，并铺平了道路，以记录打破连续波（cw）5 mA $\mathrm{H}_2^+$（相当于10 mA质子）从紧凑型回旋加速器，理想的地下安装的束流。这代表了一个重大的进步，特别是对中微子物理和高功率回旋加速器设计的影响。
From Beam to Bedside: Reinforcing Domestic Supply of $^{99}$Mo/$^{99m}$Tc using Novel High-Current D+ Cyclotrons for Compact Neutron Generation and $^{99}$Mo Production
