SPIRAL Project Research Articles

A Haskell compiler for signal transforms

Building a reusable, auto-tuning code generator from scratch is a challenging problem, requiring many careful design choices. We describe HSpiral, a Haskell compiler for signal transforms that builds on the foundational work of Spiral. Our design leverages many Haskell language features to ensure that our framework is reusable, flexible, and efficient. As well as describing the design of our system, we show how to extend it to support new classes of transforms, including the number-theoretic transform and a variant of the split-radix algorithm that results in reduced operation counts. We also show how to incorporate rewrite rules into our system to reproduce results from previous literature on code generation for the fast Fourier transform. Although the Spiral project demonstrated significant advances in automatic code generation, it has not been widely used by other researchers. HSpiral is freely available under an MIT-style license, and we are actively working to turn it into a tool to further both our own research goals and to serve as a foundation for other research groups' work in developing new implementations of signal transform algorithms.

A Hybrid Spiral Project Based Learning Model for Microprocessor Course Teaching

High demands for technology increase every day. These demands required expert engineers with high skills to keep up with technology demands. Engineering departments need to responded for this requirement to develop their educational methods. researchers began to develop educational methods and measure their effectiveness. This paper develops an educational method to educate microprocessor course. The educational model mixed the spiral method and project based learning to achieve the desirable goal. Educational activities used in the educational method like lecture, lab, and project. also, virtual lab developed to achieve better learning performance. The proposed educational method evaluated in two ways. First, statistical analysis for students’ scores shows significant differences and improvement in the learning outcome. second, students survey shows very positive impact on students learning.

An interview with Olivia Gude about connecting school and community arts practice

ABSTRACTOlivia Gude has a long and distinguished career as both a public artist and an art educator. She is currently the Angela Gregory Paterakis Professor and Chair of Art Education at the School of the Art Institute of Chicago (SAIC), where she works with graduate and undergraduate students to prepare for working as artist educators in school and community settings. Her scholarly work includes a number of articles and book chapters about art education and community art. Prof. Gude has worked as a community public artist for many years and has created over 30 large-scale mural and mosaic projects, working with intergenerational groups, teens, elders, and children. I interviewed Prof. Gude at the SAIC building in downtown Chicago to discuss how her school, university, and community art engagement as well as her work with the National Coalition for Core Arts Standards, might offer suggestions for transforming arts education for the twenty-first century and provide authentic connections between school and community. Prof. Gude discusses important enduring understandings and big ideas from the new Visual Arts National Core Arts Standards, the Spiral Workshop youth art and research project she created while at University of Illinois at Chicago, and how her experience as a community artist informs her work with students in classroom settings.

Quantified H i morphology - IV. The merger fraction and rate in WHISP

The morphology of the atomic hydrogen (HI) disk of a spiral galaxy is the first component to be disturbed by a gravitational interaction such as a merger between two galaxies. We use a simple parametrisation of the morphology of HI column density maps of Westerbork HI Spiral Project (WHISP) to select those galaxies that are likely undergoing a significant interaction. Merging galaxies occupy a particular part of parameter space defined by Asymmetry (A), the relative contribution of the 20% brightest pixels to the second order moment of the column density map (M20) and the distribution of the second order moment over all the pixels (GM). Based on their HI morphology, we find that 13% of the WHISP galaxies are in an interaction (Concentration-M20) and only 7% based on close companions in the data-cube. This apparent discrepancy can be attributed to the difference in visibility time scales: mergers are identifiable as close pairs for 0.5 Gyr but ~1 Gyr by their disturbed HI morphology. Expressed as volume merger rates, the two estimates agree very well: 7 and 6.8 x 10^-3 mergers Gyr^-1 Mpc^-3 for paired and morphologically disturbed HI disks respectively. The consistency of our merger fractions to those published for bigger surveys such as the Sloan Digital Sky Survey, shows that HI morphology can be a very viable way to identify mergers in a large HI survey. The relatively high value for the volume merger rate may be a bias in the selection or WHISP volume. The expected boon in high-resolution HI data by the planned MeerKAT, ASKAP and WSRT/APERTIF radio observatories will reveal the importance of mergers in the local Universe and, with the advent of SKA, over cosmic times.

The accelerated ISOL technique and the SPIRAL project

The accelerated ISOL technique is presented as an introduction to the present status of the SPIRAL facility. SPIRAL is based on the very high intensity light and heavy-ion beams available at GANIL. The facility will deliver radioactive beams with energies in the range between 1.7 and 25 A MeV. The current state of target-ion source production system, as well as the new developments undertaken by the target ion-source group at GANIL are presented.

The spiral project at GANIL and future opportunities

The present status of the project SPIRAL under construction at GANIL is described. Some of the specific future experimental devices such as Exogam and Vamos are shown. Future possible extensions of the SPIRAL project and, more generally, high-intensity RIB facilities are discussed.

A simulation of the temperature distribution in the SPIRAL target

We developed a model and a computer program to calculate the temperature distribution in the target which will be used in the SPIRAL project a GANIL. The results of the numerical simulation are compared with measurements performed with several types of targets.

Constraints due to the production of radioactive ion beams in the SPIRAL project

The radioactive ion beams that will be delivered by the SPIRAL facility will be produced by the interaction of a stable high energy (95 MeV/A) and high intensity (2×1013 particle/s) primary ion beam delivered by the GANIL cyclotrons with a carbon target heated to 2000 °C. During this interaction, some radioactive atoms will be created and will diffuse out of the target before entering into an electron cyclotron resonance (ECR) ion source where they will be ionized and extracted. The production of radioactive ion beams with this method implies high radiation fields that activate and can damage materials located in the neighborhood of the target. Therefore, the production system which is composed of the permanent magnet ECR ion source coupled to a graphite target will be changed after two weeks of irradiation. As this ensemble will be very radioactive, this operation has to be supervised by remote control. The radiation levels around the target–ion source system and a detailed description of the different precautions that have been taken for safety and for prevention of contamination and irradiation are presented.

News from the SPIRAL project at GANIL

The present status of the radioactive ion beam facility SPIRAL, currently under construction, is given. SPIRAL is based on the very high intensity beams which will become available in the near future at GANIL ( 2H to 40Ar at 6kW and 96A MeV). The facility will produce radioactive ion beams using the ISOL (Isotopic Separator On-Line) method and a permanent magnet ECRIS (Electron Cyclotron Resonance Ion Source) which will allow for the production of multiply charged radioactive ions. The beam will be accelerated by a K = 265 compact cyclotron and delivered to the existing experimental areas of GANIL.

Graphite target for the SPIRAL project

We present here a study of the thermal and physical properties of graphite targets for the SPIRAL project. The main objective was to develop an optimized set-up both mechanically and thermally resistant, presenting good release properties (hot targets with thin slices). We show here the results of irradiation tests concerning the mechanical and thermal resistance of the first prototype of SPIRAL target with conical geometry. We also study the micro-structural properties of the graphite target in order to check that the release properties are not deteriorated by the irradiation. Finally, we present the results concerning the latest pilot target internally heated by an electrical current. This setup has been especially designed to be used in case of low power primary beams.

New compact cyclotron design for SPIRAL

The SPIRAL project whose purpose is the production and the acceleration of radioactive nuclei is under realization at GANIL. The new facility uses a cyclotron as a post accelerator taking place behind the present machine. The energy range is 2 to 25 MeV/u according to the Q/A factor of the ions. The magnet structure (550 t) is made of 4 independent return yokes and a common circular pole piece (3.5 m in diameter) with 4 sectors. The average induction needed is 1.56 Tesla with hill and valley gaps of respectively 0.12 and 0.3 m. The required field patterns are adjusted by means of circular trim coils located between the sectors and the pole piece.

Extraction studies on electron cyclotron resonance ion sources

The production of radioactive ion beams in the SPIRAL project requires very efficient ion sources delivering beams with good optical properties. To improve these properties, the extraction conditions are under study. This paper will present the last results obtained with a new extraction system and will compare them to a numerical simulation. This comparison shows that the axial magnetic field influences the multicharged ion beam if the space charge during the acceleration is not compensated. In order to decrease the axial magnetic field effect on the extraction zone, a parallel beam can be formed with a multielectrode system. The first tests of this system will be presented.

LIONS: a new set of Fortran90 codes for the SPIRAL project at GANIL

In this paper a set of new computer programs developed at GANIL is presented. These codes are used to study different parts of the SPIRAL project, in particular the dynamics in the CIME cyclotron and the new extraction system of the ECR ion sources. Three important modules are described: CHA3D for the evaluation of 3D electric fields with or without space charge effects, LIONS for the motion of ions and EXTRACT for the ECRIS extraction. These modules are written in Fortran90 in a “data parallel scheme”. They work either on UNIX workstations or parallel and vectorial computers.

Application to the SPIRAL project at GANIL of a new kind of large acceptance mass separator

Application to the SPIRAL project at GANIL of a new kind of large acceptance mass separator

Nuclear physics with radioactive beams

Radioactive beams can be produced through two different and complementary ways: firstly by the production of radioactive nuclei at rest, followed by their acceleration using conventional techniques. This method is the best for producing low-energy radioactive beams. The second method is by the fragmentation of high-energy heavy ion beams (over 30 MeV/u), followed by the selection and purification of a given secondary beam using magnetic spectrometers. This technique leads to high-energy radioactive beams. Both methods have now been used in several laboratories in the World (Berkeley, Ganil, Louvain la Neuve, Riken, GSI Darmstadt). Examples of the corresponding experimental equipment are presented, and especially Lise 3, Sissi and the Spiral project at Ganil. Radioactive beams have been used for several purposes in nuclear physics. They constitute the fastest technique ever used for transferring exotic nuclei from the production point to a well-shielded place where detectors can be operated for studying their properties. They are used to induce nuclear reactions which reveal new information on nuclear structure. In the domain of nuclear astrophysics, radioactive beams are used to measure, through direct or indirect methods, the cross sections for reactions of crucial interest in nucleosynthesis. Finally, radioactive beams of light positron emitters, such as 19Ne have considerable interest for medical purposes and especially in the growing field of heavy-ion radiotheraphy.