ECR System Research Articles

Commissioning Results of the New Compact ECR Ion Source for Electrostatic Storage Ring at KACST

A compact microwave ECR ion source with low operating power was tested and commissioned for the ion injector line in the multipurpose low-energy ELASR storage ring facility at King Abdulaziz City for Science and Technology (KACST) in Riyadh. The compact ECR ion source can deliver singly charged ions with an energy of up to 50 keV and a beam current of up to 50 μA or up to 500 µA with a larger extraction aperture. The plasma in the ECR chamber is driven by a simple transmitter antenna, making the overall size of the ion source only 6 cm in diameter, which is relatively small when compared with other ECR systems. Additionally, the source operates without a high-voltage platform, which significantly reduces the overall footprint and simplifies the system operation. In this paper, the mechanical design and modeling of the ECR ion source are introduced, and the layout of the first part of the beam line is presented along with the numerical simulation results. In addition, the experimental results obtained for the first generated ion beam and commissioning of the ECR ion source are introduced and discussed.

Spiking Neural P Systems with Extended Channel Rules.

This paper discusses a new variant of spiking neural P systems (in short, SNP systems), spiking neural P systems with extended channel rules (in short, SNP-ECR systems). SNP-ECR systems are a class of distributed parallel computing models. In SNP-ECR systems, a new type of spiking rule is introduced, called ECR. With an ECR, a neuron can send the different numbers of spikes to its subsequent neurons. Therefore, SNP-ECR systems can provide a stronger firing control mechanism compared with SNP systems and the variant with multiple channels. We discuss the Turing universality of SNP-ECR systems. It is proven that SNP-ECR systems as number generating/accepting devices are Turing universal. Moreover, we provide a small universal SNP-ECR system as function computing devices.

Piloting Electronic Case Reporting for Improved Surveillance of Sexually Transmitted Diseases in Utah.

The Utah Department of Health (UDOH) developed an electronic case reporting (eCR) process to automatically transfer clinical data from a provider to the state health department, with aims of improving sexually transmitted disease (STD) surveillance data quality, decreasing the time spent on STD case investigations, and expanding the process to other diseases and larger healthcare systems. Reportable Conditions Trigger Codes (RCTC) were placed into the electronic health record (EHR) system at Planned Parenthood Association of Utah (PPAU) to trigger the automatic transfer of clinical data to Utah's public health surveillance system. Received data were de-duplicated, processed, and assigned directly to the public health surveillance system, with minimal manual intervention. Eighteen new data elements, important for STD case investigations, were transferred to cases with eCR. Additionally, the clinical time spent transmitting data was vastly reduced. With the new eCR process more complete and timely data is received by public health. Providers, as well as public health, now spend less time manually transmitting clinical data by fax and/or phone. Automated processes are challenging but can be achieved with a robust disease surveillance system, flexible rules engine, skillful programming, on-going analysis, and successful partnerships. The eCR process created for this project can potentially be useful for other conditions outside of STDs. Results of this demonstration project offer an opportunity for readers to learn about eCR and apply lessons learned to improve their existing eCR systems, or future public health informatics initiatives, at any state-level jurisdiction.

Fundamental Architectures of Datacenter ECR System Prototype by Applying Principle of Messaging Services

Interoperability is a component that contains information systems integration. It provides an interface from multiple data sources to support data and information integrity between various information systems. This study aims to: (1) Propose Architecture of Messaging services to support data integration of Datacenter ECR. (2) Present a fundamental architecture prototype Datacenter ECR with messaging services principle. This research is expected to provide the solution to the data integration architecture between systems that is running on HTTP protocol over internet. The integration model uses messaging services schemes and improve it with customization end-to-end encryption messages. This type of research is research and development (Research and Development) with Agile SCRUM Framework research model. It will provide any robust workflows to each step of development and management resources during design architecture and develop Datacenter ECR prototype. For the testing process, three (3) test process stages are performed: (1) White-box and (2) Black-box testing (3) Performance consistency testing

Understanding the Potential for Patient Engagement in Electronic Consultation and Referral Systems: Lessons From One Safety Net System.

To understand patient, primary care clinician (PCC), and subspecialist perspectives on potential, unexplored roles for patients in electronic consultation and referral (eCR) systems. Primary focus group and survey data collected April-November 2015. Zuckerberg San Francisco General Hospital (ZSFG) is part of an integrated public health delivery system. Its mature eCR system was first implemented in 2005. This mixed-methods study synthesizes patient, subspecialist, and PCC perspectives through two patient focus groups in English, Spanish, and Cantonese (n=6); subspecialist focus groups (n=2); and an electronic survey of all PCCs (n=222/634, 35 percent response). Focus groups were audio-recorded and transcribed. Two researchers coded the transcripts to identify recurrent themes. Survey data were analyzed using summary and bivariate statistics. Patients expressed minimal desire to directly engage in eCR, instead of emphasizing their PCC's role in advocating, informing, and finding health solutions. Subspecialists requested more consistent communication to patients about the electronic consultation process. Most PCCs (52 percent) supported patient engagement in the eCR process, particularly patient ability to track consult status and securely message with subspecialists. Results suggest a continuum of opportunities for patients and their caregivers to engage in eCR systems.

Facilitators and barriers to implementing electronic referral and/or consultation systems: a qualitative study of 16 health organizations.

BackgroundAccess to specialty care remains a challenge for primary care providers and patients. Implementation of electronic referral and/or consultation (eCR) systems provides an opportunity for innovations in the delivery of specialty care. We conducted key informant interviews to identify drivers, facilitators, barriers and evaluation metrics of diverse eCR systems to inform widespread implementation of this model of specialty care delivery.MethodsInterviews were conducted with leaders of 16 diverse health care delivery organizations between January 2013 and April 2014. A limited snowball sampling approach was used for recruitment. Content analysis was used to examine key informant interview transcripts.ResultsElectronic referral systems, which provide referral management and triage by specialists, were developed to enhance tracking and operational efficiency. Electronic consultation systems, which encourage bi-directional communication between primary care and specialist providers facilitating longitudinal virtual co-management, were developed to improve access to specialty expertise. Integrated eCR systems leverage both functionalities to enhance the delivery of coordinated, specialty care at the population level. Elements of successful eCR system implementation included executive and clinician leadership, established funding models for specialist clinician reimbursement, and a commitment to optimizing clinician workflows.ConclusionseCR systems have great potential to streamline access to and enhance the coordination of specialty care delivery. While different eCR models help solve different organizational challenges, all require institutional investments for successful implementation, such as funding for program management, leadership and clinician incentives.Electronic supplementary materialThe online version of this article (doi:10.1186/s12913-015-1233-1) contains supplementary material, which is available to authorized users.

Large Gate Swing and High Threshold Voltage Enhancement-Mode AlGaN/GaN HEMTs Using Low Energy Fluorine Ion Implantation in GaN Layer

Gallium nitride (GaN)-based high electron mobility transistors (HEMTs) is a promising candidate for high power applications. For simplify circuits design and fail-safe operation, enhancement-modes (E-mode) operation is indispensable for GaN power application. From now on, several method has been demonstrated to fabricate E-mode HEMTs, such as recessed-gate [1], p-type GaN [2], fluorine plasma implantation [3]. Mostly group report the results of fluorine plasma implantation by using the RIE, ECR system [3-4]. However, those systems cannot avoid carbon contamination implanting into the AlGaN or GaN layer and well control the fluorine concentration during the implantation. Ion implanter has been widely used in CMOS foundry, which can provide the pure fluorine ions and well-controlled dose. Recently, it is suggested that fluorine concentration in GaN layer could be more efficient to shift the threshold voltage from negative to positive region than fluorine concentration in AlGaN layer [5]. In this work, we successfully fabricate E-mode AlGaN/GaN HEMTs with large gate swing and high threshold voltage by using fluorine ion implantation in GaN layer. The AlGaN/GaN HEMT heterostructure was grown by metal-organic chemical vapor deposition (MOCVD) on silicon substrate. The epitaxial structure consisted of 2-nm GaN cap layer, 25-nm Al0.23Ga0.77N barrier layer. The ohmic contact was formed by an alloyed Ti/Al/Ni/Au metal stack. The planar isolation was created by born ion implantation. After gate window was defined by lithography, fluorine ions were directly implanted in the gate region by Varian E500HP ion implanter. Ni/Au was deposited by electron beam evaporation as the gate metal. Finally, post–metallization annealing (PMA) was carried out at 400 °C for 10 minutes in N2 ambient to repair implant damage. D-mode devices follow the same process without fluorine ion implantation. The SRIM (The Stopping and Range of Ions in Matter) simulation were used in this work to simulate fluorine ion distribution in GaN HEMTs, as shown in Fig. 1[6]. Owing to limitation of implanter, fluorine implant energy is chosen for 10 keV, 12 keV, and 15 keV. With higher implant energy, deeper fluorine ion distribution in the GaN layer and higher fluorine ion centration are demonstrated. The higher fluorine ion concentration increase the larger positive shift of threshold voltage, but severe implant damage issue should be considered. The devices feature a gate length, a gate-drain spacing, gate-source spacing and gate width, 2 um 15 um, 3 um, 50 um, respectively. The ID-VGtransfer characteristics of devices are plotted in Fig 1. For E-mode HEMTs, threshold voltage are shifted from negative to positive region by fluorine ion implantation. It is proven that higher fluorine ion concentration in GaN layer lead to the larger positive shift of threshold voltage. However, the drain current degradation are observed in fluorine devices, especially, higher implant energy (15 keV). This is suggested that severe implant damage is probably exist in the channel region. Thermal stability test is shown in Fig. 3. The fluorine device was annealed at 400 °C for 10 minutes. This result confirms that the implant damage is not fully eliminated in 15 keV fluorine devices because the drain current increase are clearly observed. Compared with 15 keV fluorine devices, 12 keV fluorine devices reveal the good thermal stability in this work. Without gate insulator, E-mode HEMTs with 12 keV fluorine ion implantation show high threshold voltage of 2.5 V, a current density of 200 mA/mm at a gate bias 5.5 V. Low energy fluorine ion implantation in GaN layer could be an effective method to fabricate the enhancement-mode AlGaN/GaN HEMTs for high power applications. Reference [1] W. B. Lanford, et al. Electronics Letters 41, pp.449-450, Mar 2005. [2] Y. Uemoto, et al. IEEE Transactions on Electron Devices, vol. 54, pp. 3393-3399, Dec. 2007 [3] Y. Cai, et al. IEEE Electron Device Letters, vol. 26, pp. 435-437, Jul. 2005. [4] Yuhao Zhang, et al. Appl. Phys. Lett. 103, 033524, 2013. [5] S. Hamady, et al. 2013 15th European Conference onPower Electronics and Applications (EPE), pp. 1–6, 2013. [6] http://www.srim.org/ Figure 1

Characteristics of electron cyclotron resonance plasma formed by lower hybrid current drive grill antenna

A 3.7 GHz system, which is meant for LHCD experiments on ADITYA tokamak, is used for producing ECR discharge. The ECR discharge is produced by setting the appropriate resonance magnetic field of 0.13 T, with hydrogen at a fill pressure of about 5 × 10−5 Torr. The RF power, up to 10 kW (of which ∼50% is reflected back), with a typical pulse length of 50 ms, is injected into the vacuum chamber of the ADITYA tokamak by a LHCD grill antenna and is used for plasma formation. The average coupled RF power density (the RF power/a typical volume of the plasma) is estimated to be ∼5 kW/m3. When the ECR appears inside the tokamak chamber for the given pumping frequency (f = 3.7 GHz) a plasma with a density (ne) ∼ 4 × 1016 m−3 and electron temperature ∼8 eV is produced. The density and temperature during the RF pulse are measured by sets of Langmuir probes, located toroidally, on either side of the antenna. Hα signals are also monitored to detect ionization. An estimate of density and temperature based on simple theoretical calculation agrees well with our experimental measurements. The plasma produced by the above mechanism is further used to characterize the ECR-assisted low voltage Ohmic start-up discharges. During this part of the experiments, Ohmic plasma is formed using capacitor banks. The plasma loop voltage is gradually decreased, till the discharge ceases to form. The same is repeated in the presence of ECR-formed plasma (RF pre-ionization), formed 10 ms prior to the loop voltage. We have observed that (with LHCD-induced) ECR-assisted Ohmic start-up discharges is reliably and repeatedly obtained with reduced loop voltage requirement and breakdown time decreases substantially. The current ramp-up rates also decrease with reduced loop voltage operation. These studies established that ECR plasma formed with LHCD system exhibits similar characteristics as reported earlier by dedicated ECR systems. This experiment also addresses the issue of whether ECR plasma formed with grill antenna exhibits similar behavior as that formed by single waveguide ECR antenna. Our experimental observations suggest that the characteristics of (LHCD system-induced) ECR-assisted Ohmic start-up discharges show similar properties, reported earlier with normal ECR-assisted Ohmic start-up discharges and hence LHCD system may be used as ECR system at reduced toroidal magnetic field for other applications like wall conditioning.

Near-Field Distribution of Radial Line Slot Antenna for Surface-Wave-Coupled Plasma Generation

In plasma processing systems for large-size wafers, quick evacuation of reaction gas by making the process space narrow is urgently required to realize higher productivity and better quality for microelectronic devices. Wafers must be placed close to the antenna aperture in this case. A radial line slot antenna (RLSA) for surface-wave-coupled plasma (SWP) is a promising candidate to this end. A novel slot arrangement in the aperture, consisting of densely arrayed transverse slots, was fabricated and tested. A uniform, high-density (3×1011 cm-3) and large-area plasma at low electron temperature has already been realized in previous experiments. It dispenses with the DC magnetic fields required in ECR systems. For further development of the slot design, as well as the mechanism determination of plasma generation, in this paper we evaluate the electromagnetic near fields of SWP-RLSAs. As the first step, antennas in free space without the plasma as well as a glass vacuum window, are analyzed using a periodic array model. The predicted near-field distribution is compared with those of previous experiments and a reasonable agreement is reported.

The electron cyclotron resonance (1+n+) systems and the ISOL radioactive beam facilities (invited)

Short life radioactive beams presently need charge breeders either for continuous or pulsed postaccelerators. Until recently these charge breeders were mainly based on stripper foils and or electron beam ion source projects associated with ion trap bunching devices. In 1995 however, we demonstrated the feasibility of radioactive electron cyclotron resonance ion source (ECRIS) charge breeders with rather good efficiencies working in continuous regime and well adapted for continuous postaccelerators. In 1998, we demonstrated also the feasibility of pulsed ECR ion traps (ECRITs) which are well adapted for pulsed postaccelerators with short life radioactive ion bunches. In this article, we explain the basic principles of these devices shortly named (1+n+) ECR systems and compare their characteristics with other systems. More precise results are given in companion articles at this meeting.

Formation of Carbon Films from C2H6–H2 by ECR Plasma CVD by Application of a Negative DC Bias

Abstract Hydrogenated amorphous carbon films were prepared from a C2H6–H2 system by ECR plasma CVD. A negative DC bias ranging 0 — −200 V applied to the ECR system induced an additional DC discharge to give an abrupt increase in the emission intensity of plasma beyond −110 V bias, where a soft (micro Vickers hardness of about 2 GPa) but flat surface with fine grains was formed.

Ion Polishing of ZnO Films by an ECR System

SAW filters in the ZnO/IDT/glass type have periodic convexes of the same thickness as the IDT electrodes caused by the presence of IDT on the ZnO film surface and fine irregularities all over the ZnO film surface. These unevenness affects the SAW velocity dispertion. An attempt to smooth the unevenness, using the inclination effect in the ion polishing process, resulted in observation of an interesting surface smoothing phenomenon such as narrowing of the width of convex portions caused by IDT on ZnO film surface, smoothing of small convex spots of fine irregularities found all over the ZnO film surface, etc.