Emittance measurements and operation optimization for ECR ion sources

Electron Cyclotron Resonance (ECR) ion sources supply a broad range of ions for post acceleration in cyclotrons. Here, an effort to improve the beam transfer from RIKEN's 18 GHz superconducting ECR ion source (SC ECRIS) to the Low Energy Beam Transfer (LEBT) line and an optimization of the performance of the ion source is presented. Simulation studies have shown that less than 20% of the beam is currently transferred. The first goal is to measure the transverse beam emittance in real time. The emittance monitor designed and fabricated for this purpose utilizes a pepper pot plate followed by a transparent scintillator and a CMOS camera for image capture. The second goal is to investigate on dependencies between beam emittance and various operating parameters. To this extent, modifications of the ion source took place, as well as a measurement of the magnetic field inside the ion source. In this contribution the design details of the instrument and a description of the algorithm are presented as well as a typical emittance measurement

A One-Pot Three-Component Double-Click Method for Synthesis of [⁶⁷Cu]-Labeled Biomolecular Radiotherapeutics

© 2017 The Author(s).A one-pot three-component double-click process for preparing tumor-targeting agents for cancer radiotherapy is described here. By utilizing DOTA (or NOTA) containing tetrazines and the TCO-substituted aldehyde, the two click reactions, the tetrazine ligation (an inverse electron-demand Diels-Alder cycloaddition) and the RIKEN click (a rapid 6π-azaelectrocyclization), could simultaneously proceed under mild conditions to afford covalent attachment of the metal chelator DOTA or NOTA to biomolecules such as to albumin and anti-IGSF4 antibody without altering their activities. Subsequently, radiolabeling of DOTA-or NOTA-attached albumin and anti-IGSF4 antibody (an anti-tumor-targeting antibody) with [67Cu], a β--emitting radionuclide, could be achieved in a highly efficient manner via a simple chelation with DOTA proving to be a more superior chelator than NOTA. Our work provides a new and operationally simple method for introducing the [67Cu] isotope even in large quantities to biomolecules, thereby representing an important process for preparations of clinically relevant tumor-targeting agents for radiotherapy

A new possibility of low-Z gas stripper for high power uranium beam acceleration alternative to C-foil

The RIKEN accelerator complex started feeding the next-generation exotic beam facility RIBF (RadioIsotope Beam Factory) with heavy ion beams from 2007 after the successful commissioning at the end of 2006. Many elaborating improvements increased the intensity of the various heavy ion beams from 2007 to 2010. However, the available beam intensity especially of uranium beam is far below our goal of 1 p{micro}A (6 x 10{sup 12} particle/s). In order to achieve it, upgrade programs are well in progress, including constructions of a new 28 GHz superconducting ECR ion source and a new injector linac. However, the most serious problem of the charge stripper for uranium beam is still open although many elaborating R&D works for the problems. Equilibrium charge state in gas generally is much lower than that in carbon foil due to its density-effect. But gas stripper is free from the problems originated from its lifetime and uniformity in thickness. Such merits pushed us think about low-Z gas stripper to get higher equilibrium charge state even in gas. Electron loss and capture cross section of U ion beams in He gas were measured as a function of their charge state at 11, 14 and 15 MeV/u. The extracted equilibrium charge states from the cross point of the two lines of the cross sections were promisingly higher than those in N{sub 2} gas by more than 10. The plasma window is expected to be a key technology to solve the difficulty in accumulation of such thick as about 1 mg/cm{sup 2} of low-Z gas

Circuit-model representation of external-Q calculation

A new representation of the external-Q (Q_{ext}) calculations for cavities coupled to waveguides is derived based on a circuit model. The Q_{ext} value is obtained by solving analytical equations of the input impedance of a cavity provided as a function of the frequency; large numerical simulations are not necessary. The derivation starts with a fundamental expression of the ratio of the stored energies of two loss-free circuits forming a parallel resonant circuit. By applying this expression to the input impedance of a cavity seen from the detuned-short-circuit plane, as well as to those of open- and short-end waveguides, a precise estimation of Q_{ext} is given. It is then explained that the result is almost independent of the choice of the cavity boundary. This method is an alternative to the electromagnetic representation of the Q_{ext} calculation [P. Balleyguier, in Proceedings of the XIX International Linac Conference, Chicago, Illinois, USA, edited by C. E. Eyberger, R. C. Pardo, and M. M. White (ANL-98/28, 1998), pp. 133–135.]. It is also shown why this estimation provides a good approximation when Q_{ext} is high. Formulas for the TEM, TE, and TM modes of waveguides are presented along with a simple example of a loop-coupled cavity

DEFORMATION AND CRACKING OF METAL-DEPOSITED CERAMICS AND EFFECTS OF ION IRRADIATION

Le dépôt de couches minces de Zr ou Ag et l'irradiation par des ions Ar+ augmentent de manière coopérative la résistance des saphirs à la fracture par rayure. Le dépôt de ces couches minces semble provoquer un adoucissement de la céramique.Deposition of Zr or Ag thin film and Ar+ ion irradiation increases cooperatively the durability of sapphire against cracking by scratching. The deposition of the thin films were found to cause the softening of ceramics