Super Collider Research Articles

Beam power scale-up in micro-electromechanical systems based multi-beam ion accelerators.

We report on the development of multi-beam radio frequency (RF) linear ion accelerators that are formed from stacks of low cost wafers and describe the status of beam power scale-up using an array of 112 beams. The total argon ion current extracted from the 112-beamlet extraction column was 0.5 mA. The measured energy gain in each RF gap reached as high as 7.25 keV. We present a path toward using this technology to achieve ion currents >1 mA and ion energies >100 keV for applications in material processing.

Neutron spectra at a high energy heavy ion accelerator measured with a TLD-based Bonner spectrometer.

A Bonner sphere spectrometer with TLD cards as sensitive elements was constructed and used at the GSI accelerator complex to measure the neutron spectral fluence rates for radiation safety purposes. The neutron spectra were measured in the synchrotron tunnel during 550 MeV/u 40Ar beam operation and in Cave A experimental area with a 1 GeV/u 56Fe beam impinging on a thick aluminum target. Unfolded spectra were compared with those calculated using the Monte Carlo code FLUKA. The measured spectra show a good agreement with the simulations and the set proved itself to be a useful tool for different radiation safety purposes.

Measurement and Protection of Induced Radioactivity in Proton Heavy Ion Accelerator Therapy

Measurement and Protection of Induced Radioactivity in Proton Heavy Ion Accelerator Therapy

Measurement on the desorption yields of ceramic and Au-coated ceramic irradiated with Bi32+ and Xe23+

The Booster Ring (BRing) is the key part of the High Intensity Heavy Ion Accelerator Facility (HIAF). In order to reduce the eddy current effect, specifically developed stainless steel vacuum chambers with ultra-thin (0.3 mm) walls and ceramic spacers will be used. Desorption yields experiments were carried out on spacers made of zirconia ceramic, on zirconia ceramic coated with different Au thicknesses and coating processes, as well as on zirconia ceramic coated with getter films. A dedicated mass spectrometer was used to analyze the changes in the gas composition during the bombardment. The results show that Au-coated zirconia ceramic can effectively lower the desorption yields, the higher the Au coating thickness, the lower the desorption yield. When the beam impinges on the surface of the zirconia ceramic, the pressure randomly fluctuates, without showing any clear long term beam cleaning effect. As far as the coating process is concerned, samples coated by magnetron sputtering show higher desorption yields than those electroplated. However, the electroplating process is characterized by a low bonding force between the films and the ceramic substrate, which makes possible for the film to peel off under beam bombardment. Finally, TiN-coated zirconia ceramic has better static vacuum performances. However, due to its strong H2 absorption capacity, TiN coated samples will release more H2 under bombardment, thus providing a worse dynamic vacuum conditions. Practical consequences for the BRing vacuum system of the HIAF are given.

J. David Jackson (January 19, 1925–May 20, 2016): A Biographical Memoir

John David (“Dave”) Jackson, a Canadian-born theoretical physicist, contributed significantly to particle, nuclear, and atomic physics. He is best known, however, for his text Classical Electrodynamics, which has been a fixture in physics graduate education around the world for more than 50 years. It is generally referred to simply as “Jackson.” This textbook, which has inspired fear and wonder alike in generations of students, clearly reflects the author's fascination with physical phenomena, his renowned mathematical dexterity, and his appreciation of the elegance of physical laws. Jackson's major contributions to research included the theory of muon-catalyzed fusion; the analysis, with Kurt Gottfried, of angular distributions in quasi-two-body elementary particle collisions; and the elucidation of charmonium-state decays. Jackson influenced the development of physics research throughout the United States as well as internationally—particularly through his work on the nascent Superconducting Super Collider. An active promoter of civil liberties and human rights, he was one of the leaders of the efforts to free Andrei Sakharov, Yuri Orlov, and Anatoly Shcharansky from Soviet imprisonment.

Superconducting properties of commercial REBCO-coated conductors with artificial pinning centers

Over the last 20 years, technologies for manufacturing rare-earth barium copper oxide (REBCO)-coated conductors have undergone a steady development. Currently, the properties of these conductors are reasonably stable owing to the intensive efforts of the manufacturers. However, for high-field magnet applications, such as the magnets used in nuclear magnetic resonance instruments, accelerators, and fusion reactors, further enhancements in the current-carrying capabilities and/or the current densities of the conductors under a high magnetic field are necessary. Recently, several conductors doped with artificial pinning centers (APCs) have become commercially available, primarily from four manufacturers: Fujikura, Shanghai ST, SuperOx, and SuperPower. In this study, we characterized these relatively new conductors from the viewpoint of a magnet designer. We measured the critical currents (I c) of full-size 4 mm wide conductors in a wide field range at 4.2 K and 77 K; we also measured the critical temperatures. The measurement results showed that the I c values at 4.2 K under perpendicular fields for these conductors are significantly greater than those of non-APC conductors; for the 4 mm wide conductors, the I c values are in the range of 300–740 A and 450–1000 A at 18 T and 12 T, respectively. Furthermore, we clarified that the non-Cu current density (J c) at 4.2 K for some of the investigated conductors is more than twice the J c of the recent Nb3Sn conductors in fields exceeding 15 T. In the investigated commercial REBCO-APC conductors, the highest layer J c of ∼60 kA mm−2 (at 18 T and 4.2 K) was noted. We also investigated the I c–B relationship at 4.2 K for the recent REBCO-APC conductors.

Quantum Legacies: Dispatches from an Uncertain World

Quantum Legacies: Dispatches from an Uncertain World

Schemes for producing multi-energy fast neutrons using a low-energy ion accelerator

In this article we explore neutron producing schemes using a compact accelerator for producing fast neutrons for nuclear data measurements relevant to GEN-IV reactors and Accelerator Driven Systems and also for other applications such as radioisotopes production. The compact accelerator which consists of an Electron Cyclotron Resonance ion source along with a Radio Frequency Quadrupole and Drift Tube Linac is expected to provide p,d and 7Li beams of energies in the range of 0.5–3 MeV/u. Two different neutron producing schemes are examined for their suitability for the above mentioned applications. In the first scheme, using the 7Li(d,n)2 4He reaction, a variety of neutron energies ranging from 1 MeV to 16 MeV with reasonable flux and energy-time characteristics can be generated making it suitable for studies in (n,cp), (n,f) and (n,Xn) reactions important for nuclear fusion technology, security applications and radioisotope production. In the second scheme, the p(7Li,n)7Be reaction can be used to produce quasi mono-energetic neutrons in inverse kinematics mode with very little background making it suitable for high precision nuclear data measurements relevant to GEN-IV reactors and Accelerator Driven Systems.

First Experience of Production and Testing the Superconducting Quadrupole and Corrector Magnets for the SIS100 Heavy Ion Accelerator of FAIR

First Experience of Production and Testing the Superconducting Quadrupole and Corrector Magnets for the SIS100 Heavy Ion Accelerator of FAIR

Forward experiment sensitivity estimator for the LHC and future hadron colliders

We introduce a numerical package FORward Experiment SEnsitivity Estimator, or $\mathtt{FORESEE}$, that can be used to simulate the expected sensitivity reach of experiments placed in the far-forward direction from the proton-proton interaction point. The simulations can be performed for 14 TeV collision energy characteristic for the LHC, as well as for larger energies; 27 and 100 TeV. In the package, a comprehensive list of validated forward spectra of various SM species is also provided. The capabilities of $\mathtt{FORESEE}$ are illustrated for the popular dark photon and dark Higgs boson models, as well as for the search for light up-philic scalars. For the dark photon portal, we also comment on the complementarity between such searches and dark matter direct detection bounds. Additionally, for the first time, we discuss the prospects for the LLP searches in the proposed future hadron colliders: High-Energy LHC (HE-LHC), Super proton-proton Collider (SppC), and Future Circular Collider (FCC-hh).

Discriminative detection of laser-accelerated multi-MeV carbon ions utilizing solid state nuclear track detectors

A new diagnosis method for the discriminative detection of laser-accelerated multi-MeV carbon ions from background oxygen ions utilizing solid-state nuclear track detectors (SSNTDs) is proposed. The idea is to combine two kinds of SSNTDs having different track registration sensitivities: Bisphenol A polycarbonate detects carbon and the heavier ions, and polyethylene terephthalate detects oxygen and the heavier ions. The method is calibrated with mono-energetic carbon and oxygen ion beams from the heavy ion accelerator. Based on the calibration data, the method is applied to identify carbon ions accelerated from multilayered graphene targets irradiated by a high-power laser, where the generation of high-energy high-purity carbon ions is expected. It is found that 93 ± 1% of the accelerated heavy ions with energies larger than 14 MeV are carbons. The results thus obtained support that carbon-rich heavy ion acceleration is achieved.

CONSTRUCTIONAL MATERIALS EXPERIMENTAL RESEARCHES ON THE HELIUM IONS LINEAR ACCELERATOR

The basic parameters of an irradiation and their registration system for constructional materials irradiated on the helium ions linear accelerator are resulted. Experimental techniques and some researches results of the microscopic, electrophysical, frictional and ultrasonic characteristics of atomic power stations (APS) and fusion reactors (FR) constructional materials irradiated on a linear accelerator of the helium ions with energies 0.12 and 4 MeV are presented.

The energy calibration of the IFIN-HH 3 MV Tandetron accelerator for alpha particles

Ion accelerators have a fundamental role in atomic and nuclear studies as well as in applied physics, including the modification and characterization of materials. The precise knowledge of the energy of accelerated ions is of utmost importance, especially for cross-section measurements or for accurate depth profiling using narrow resonances. The 3 MV Cockcroft–Walton tandem accelerator of IFIN-HH from HVEC was installed in 2012. The machine is mainly dedicated to ion beam analysis, ion implantation, and astrophysics studies at low energy. In this work, we report on the first calibration for alpha particles of the terminal voltage using a technique based on Rutherford backscattering spectrometry measurements. The energies of the α particles from a mixed spectroscopic 239Pu + 241Am α source are compared with the energies of 4He projectiles backscattered into a silicon detector by carbon and gold layers. The position of the 16O(α,α) 16O resonance around 3.038 MeV at backscattering angles of 145° and 165° was remeasured. Our results are compared with recent results reported in the literature.

RF Power Generating System for the Linear Ion Accelerator

RF Power Generating System for the Linear Ion Accelerator

Certification testing of production superconducting quarter-wave and half-wave resonators for FRIB

The Facility for Rare Isotope Beams (FRIB) is designed to accelerate ion beams to ≥ 200 MeV per nucleon with 46 superconducting radio-frequency cryomodules. The FRIB driver linac uses quarter-wave resonators and half-wave resonators; with a total of 324 resonators, the linac is currently the largest heavy ion accelerator in the world. Production of jacketed resonators began in January 2014 and was completed in December 2019. Dewar certification testing of all the cavities was done before they were installed into cryomodules. The experience and lessons from more than 5 years of FRIB resonator production and certification testing are analyzed and summarized in this paper.

Design and implementation of module fault interlock and protection system of HIAF-BRing power supply prototype

Power supply prototype in High Intensity heavy ion Accelerator Facility-Booster Ring (HIAF-BRing) adopts the scheme of full energy and fast cycle storage pulse power supply topology. Its multi modules are connected in series and parallel pattern, and the power reaches megawatt level. Due to the high power and large scale of the power supply, a module fault interlock protection system based on Programmable Logic Controller (PLC), interlock boards and Field Programmable Gate Array (FPGA) is designed and implemented to protect the power supply in operation. In this paper, first, a design of double redundant module fault interlock is introduced. Second, the logic implemented in PLC is described. Third, the work about FPGA is given. Finally, the system is tested in three aspects: the responsive time of the power supply interlock loop, the total time from controller error occurrence to interlock finish, and the equipment fault response. The result shows that the module fault interlock system can action sensitively, timely and reliably in case of fault occurrence, which meets the requirements of the power supply prototype in HIAF-BRing.

Radiation reaction of betatron oscillation in plasma wakefield accelerators

A classical model of radiation reaction for the betatron oscillation of an electron in a plasma wakefield accelerator is presented. The maximum energy of the electron due to the longitudinal radiation reaction is found, and the betatron oscillation damping due to both the longitudinal and transverse radiation reaction effects is analyzed. Both theoretical and numerical solutions are shown with good agreements. The regime that the quantum radiation takes effect is also discussed. This model is important for designing future plasma based super accelerators or colliders.

Vacuum system for EBIS charge breeder of the RAON heavy ion accelerator

An Electron Beam Ion Source (EBIS) will be utilized for charge breeder in the RAON heavy ion accelerator facility. The vacuum system for the RAON EBIS charge breeder is crucial part for the achievable charge state, breeding efficiency, and purity of the charge-bred beam. A strict vacuum level of about 10−11 mbar is required in the ion trap. The pumping system of the RAON EBIS charge breeder consists of turbo pumps (TMPs), cryo-pumps, and non-evaporable getter (NEG) ZAO modules. The material for the ion trap structures and vacuum chamber was chosen and handled carefully to satisfy the vacuum requirements in the manufacturing step with vacuum firing at 1050 °C for 2 h. A vacuum test of the ion trap section has been performed with baking, and final vacuum level reached 2.3 × 10−11 mbar. In this paper, the vacuum system of the RAON EBIS and test procedures and results are presented and discussed.

Design study of reflection time-of-flight mass spectrometer for EBIS charge breeder

In this study, a time-of-flight mass spectrometer is developed to analyze the mass-to-charge ratio of ion beams generated from an electron beam ion source (EBIS) at the RAON heavy ion accelerator facility. The time-of-flight mass spectrometer comprises a Bradbury–Nielson gate, steerer, mirror electrode, and microchannel plate detector. The Bradbury–Nielson gate is applied to generate a bunch beam with a 5-ns pulse width at the front end of the time-of-flight system. A double-stage reflector is employed to obtain a beam chromatic correction from the energy spread of the ion beam generated from the EBIS. The design is created through optics simulation using the SIMION code, with 133Cs as the reference ion. Consequently, the charge state of 27+ separated from neighboring states at a maximum voltage of 20 kV is obtained. By utilizing ion sources of Cs1+ (m/z 133) and Rb1+ (m/z 85 and m/z 87) to perform the performance test on the designed TOFMS system, the spectral peak of the ion sources and a relatively high mass resolution are obtained. This paper introduces the development process and test results of the time-of-flight mass spectrometer in detail.

Ion Accelerator Facility of the Wakasa Wan Energy Research Center for the Study of Irradiation Effects on Space Electronics

The core facility of the Wakasa Wan Energy Research Center (WERC) consists of three ion accelerators: a synchrotron, a tandem accelerator and an ion-implanter. Research on the irradiation effects using these accelerators has been performed on space electronics such as solar cells, radiation detectors, image sensors and LSI circuits. In this report, the accelerator facility and ion-irradiation apparatuses at WERC are introduced, focusing on the research on irradiation effects on space electronics. Then, some recent results are summarized.