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Due to the popularity and flexibility of Minecraft, educators have used this game to develop instructional materials and activities to cultivate student interests in science, technology, engineering and mathematics (STEM). One example of such an initiative is the What-If Hypothetical Implementations in Minecraft (WHIMC) project of the University of Illinois Urbana Champaign. The study reported in this paper describes a WHIMC deployment in the Philippines and the effects this deployment had on student STEM interest. The study used quantitative and qualitative methods to determine the effect of WHIMC on the STEM interest of Filipino students. We performed quantitative analysis of the pre- and post-STEM Interest Questionnaire (SIQ) ratings and Game Experience Questionnaire (GEQ) ratings of the high- and low-performers to determine the effect of using WHIMC in the students’ STEM interest and the difference between the game experience of high- and low-performers, respectively. Qualitative analysis of the answers to the open-ended questions about the attributes of the module was also conducted to determine the relationship between the module attributes and student performance. The analysis of the aggregated SIQ ratings before and after using the WHIMC-based modules revealed only a minimal effect on the STEM interests of the students. However, there was a significant effect in the Choice Actions construct, which implies that students recognize the importance of studying hard if they want to pursue STEM-related careers. Further, the analysis of the overall GEQ of high-performers and low-performers also revealed no significant difference. Although no significant difference was observed in the overall GEQ, high-performers had significantly higher GEQ ratings in the Immersion dimension. This result suggested that high-performers had a more positive, engaging, and enjoyable learning experience. Moreover, the findings on the favorite module attributes suggested that students perform better in the out-of-game assessments when they like all the module attributes. This implies that students must be engaged in the game and learning task aside from being interested in the learning topic to have better assessment scores. The study also showed that open-ended learning environments coupled with tasks that demand exploration, observation, and higher-ordered thinking are demanding even on high-performers.

Disintegration of C-12 nuclei by tagged photons of 700-1500 MeV energy at the GRAAL facility has been studied by means of the LAGRAN gamma E detector with a wide angular acceptance. The energy and momentum distributions of produced neutrons and protons as well as their multiplicity distributions were measured and compared with corresponding distributions calculated with the RELDIS model based on the intranuclear cascade and Fermi break-up models. It was found that eight fragments are created on average once per about 100 disintegration events, while a complete fragmentation of C-12 into 12 nucleons is observed typically only once per 2000 events. Measured multiplicity distributions of produced fragments are well described by the model. The measured total photoabsorption cross section on C-12 in the same energy range is also reported. (C) 2015 Elsevier B.V. All rights reserved.

Compton backscattering gamma ray beams are characterized by a high degree of linear and circular polarization with low unpolarized backgrounds and have proven to provide very precise measurements of polarization observables. Latest results from LEGS and GRAAL experiments on proton and deuteron targets are presented. The Σ beam asymmetry for ω photoproduction has been measured by the GRAAL collaboration for both the ω→π0γ and the ω→π+π−π0 decay channels on the proton target; single and double polarization asymmetries have been provided also for the K photoproduction channel. E and G double polarization asymmetries for single pion photoproduction on the proton and deuteron have been measured at LEGS using a frozen spin HD target.

Based on the high sensitivity of Compton scattering off ultra relativistic electrons, the possibility of anisotropies in the speed of light is investigated. The result discussed in this contribution is based on the gamma-ray beam of the ESRF's GRAAL facility (Grenoble, France) and the search for sidereal variations in the energy of the Compton-edge photons. The absence of oscillations yields the two-sided limit of 1.6 x 10^{-14} at 95 % confidence level on a combination of photon and electron coefficients of the minimal Standard Model Extension (mSME). This new constraint provides an improvement over previous bounds by one order of magnitude., Comment: Talk presented at the Fifth Meeting on CPT and Lorentz Symmetry, University of Indiana, June 28-July 2, 2010

The preliminary results obtained by the GRAAL collaboration for the π0π+ photoproduction on the free and quasi-free proton (deuteron) at Eγ = 0.7-1.5 GeV are presented. The total cross section of the γp → π0π+n reaction and invariant mass spectra for the π+π0, π+n and π0n systems are presented in the photon energy range from 0.7 to 1.5 GeV. These results are in good agreement with the 2π-MAID calculations.

The possibility of anisotropies in the speed of light relative to the limiting speed of electrons is considered. The absence of sidereal variations in the energy of Compton-edge photons at the ESRF's GRAAL facility constrains such anisotropies representing the first non-threshold collision-kinematics study of Lorentz violation. When interpreted within the minimal Standard-Model Extension, this result yields the two-sided limit of 1.6 x 10^{-14} at 95% confidence level on a combination of the parity-violating photon and electron coefficients kappa_{o+} and c. This new constraint provides an improvement over previous bounds by one order of magnitude., Comment: 4 pages, 4 figures

International audience; In the framework of investigation of meson photo-production on proton and neutron in a deuterium target at the GRAAL experiment, we present a method to identify the vertex of interaction when in reaction products there are at least two charged particles, by the information provided by the cylindrical multiwire proportional chambers. By this device, we are able to obtain the direction of charged particles that leave the target after a photo-production reaction. For each charged particle, the device provides the coordinates of two points in the laboratory reference system, and the z-axis represents the beam direction. We calculate the trajectory of each charged particle and its cross point, representing the vertex of the reaction.

The $ \Sigma$ beam asymmetry in the photoproduction of neutral pions from quasi-free nucleons in a deuteron target was measured for the first time between 0.60 and 1.50GeV, with the GRAAL polarized and tagged photon beam. The asymmetry values from the quasi-free proton were found equal to the ones extracted from a pure proton target. The asymmetries from quasi-free proton and quasi-free neutron were found equal up to 0.82GeV and substantially different at higher energies. The results are compared with recent partial-wave analyses.

We present the first measurement of the {sigma} beam asymmetry in {eta} photoproduction on the neutron in the photon energy range from threshold to 1.5 GeV. Data have been collected by using the tagged and linearly polarized photon beam and the large solid angle apparatus of the GRAAL facility. Neutron data have been selected among {eta} photoproduction events on the deuteron in the quasi-free kinematics approximation. Proton data, extracted in the same way, are within errors identical to those previously obtained on free protons at the GRAAL facility, except for a few points falling in certain energy bins. This difference is, however, well understood in terms of the Fermi motion of the nucleons in the deuteron. We take the consistency of free and quasi-free proton data as an indication that nuclear effects are negligible also for neutron data. The ETAMAID model, in which a strong coupling of the D{sub 15}(1675) resonance to the {eta}-neutron channel is introduced, can explain the proton data very well, but it cannot describe the beam asymmetry for the neutron.

The GRAAL tagged and polarized γ beam has been operating with a maximum energy of 1100 MeV. For the first time asymmetry results in ν photoproduction were obtained and will be shown. Interesting results have also been obtained for π0 and π+ photo-production, that largely confirm the already existing ones, but also extend in not yet explored angular and energetic regions, especially for backward scattering and energies greater than 900 MeV.

The reaction d(\vec\gamma,np) has been studied using the tagged and polarised LADON gamma ray beam at an energy 30 - 50 MeV to investigate the existence of narrow dibaryonic resonances recently suggested from the experimental measurements in a different laboratory. The beam was obtained by Compton back-scattering of laser light on the electrons of the storage ring ADONE. Photo-neutron yields were measured at five neutron angle \vartheta_n = 22, 55.5, 90, 125 and 157 degrees in the center of mass system.Our results do not support the existence of such resonances., Comment: 16 pages, Latex, 22 figures, 1 table. Nucl. Phys. A to appear

We describe the electromagnetic calorimeter built for the GRAAL apparatus at the ESRF. Its monitoring system is presented in detail. Results from tests and the performance obtained during the first GRAAL experiments are given. The energy calibration accuracy and stability reached is a small fraction of the intrinsic detector resolution., 19 pages, 14 figures, submitted to Nuclear Instruments and Methods

The GRAAL facility produces a highly polarized gamma-ray beam by Compton scattering of laser photons on the electrons of the European Synchrotron Radiation Facility (ESRF) at Grenoble. Preliminary results have been obtained with the LAGRANGE detector showing its excellent performances.

The {sup 28}Si({gamma}{searrow},{ital np}){ital X} reaction has been studied using the Ladon polarized and tagged {gamma}-ray beam, in the energy region between 50 and 75 MeV. The data have been compared with the {ital quasideuteron} mechanism. At the highest photon energy the applied model leads to a satisfactory description of both the unpolarized cross section and beam polarization asymmetry. {copyright} {ital 1996 The American Physical Society.}

We simulate an experiment of ν photoproduction on the nucleon performed with a 4 π BGO electromagnetic calorimeter and a Compton backscattering tagged beam of 1.5 GeV maximum energy to extract information on background suppression and trigger settings. The simulation is possible by the application of an event generator that reproduces the photon-nucleon interaction from the pion threshold up to 4 GeV.

The behaviour of BGO sectors, designed for an electromagnetic calorimeter to be operated at up to 2 GeV, is considered in relation to the different terms that contribute to the overall BGO resolution and to the techniques that can be adopted to reduce them to a minimum. In particular, the measurements of light collection uniformity and energy resolution obtained on a large number of sectors are reported, and their effect on the overall BGO resolution analyzed.

The response to monoenergetic protons of 24 cm long pyramidal BGO sectors, designed for a 4π spectrometer, was measured up to 173 MeV by scattering 200 MeV protons off a polyethylene target. The experimental results are compared with lower energy results and Monte Carlo calculations performed with a modified version of the GEANT code.

We present the first measurements of the gamma-ray beam energy resolution obtained with a new tagging system for the Ladon facility on the storage ring Adone at Frascati. A resolution of the order of 3% in the energy region of 30-80 MeV is obtained in accordance with predictions.

Experimental fissility data from photofission reactions of $^{232}\mathrm{Th}$, $^{238}\mathrm{U}$, and $^{235}\mathrm{U}$ nuclei at 52 MeV have been obtained using monochromatic and polarized photon beams and dielectric fission-track detectors. These data, along with literature data for $^{237}\mathrm{Np}$, $^{235,238}\mathrm{U}$, $^{232}\mathrm{Th}$, $^{209}\mathrm{Bi}$, $^{208}\mathrm{Pb}$, and $^{174}\mathrm{Yb}$ nuclei have been analyzed within the framework of a simple two-step model for photofission reactions, i.e., absorption of the incident photon by a neutron-proton pair followed by an evaporation-fission competition mechanism for the excited nucleus. For nuclei in the Ta-Np region the trend of calculated fissilities clearly shows shell effects in the vicinity of $^{208}\mathrm{Pb}$. In the case of $^{238}\mathrm{U}$ the effect of photon polarization on fission direction has also been studied, and isotropy was observed in the fragment azimuthal distribution.

Measurement of the asymmetry factor in D(γ, np) is reported and the result is discussed in the framework of Partovi’s theory.

The reaction $^{2}(\ensuremath{\gamma}$,p)n has been studied using a monochromatic and polarized gamma ray beam at energies ${E}_{\ensuremath{\gamma}}$=19.8, 29.0, 38.6, and 60.8 MeV. The beam of an intensity \ensuremath{\sim}4\ifmmode\times\else\texttimes\fi{}${10}^{5}$ \ensuremath{\gamma}/sec was obtained by Compton back scattering of mode-locked laser light off electron bunches in the Adone storage ring. Photoneutron yields were measured at nine neutron angles ${\mathrm{theta}}_{\mathrm{n}\mathrm{\ensuremath{\simeq}}}$15, 30, 45, 60, 90, 120, 135, 150, and 165 deg in the center of mass (c.m.) for ${E}_{\ensuremath{\gamma}}$=19.8, 29.0, and 38.6 MeV, and at ${\mathrm{theta}}_{\mathrm{n}\mathrm{\ensuremath{\simeq}}}$30, 60, 90, 120, and 150 deg c.m. for ${E}_{\ensuremath{\gamma}}$=60.8 MeV. The polarization independent component ${I}_{0}$(theta) of the differential cross section and the polarization dependent component ${\mathrm{PI}}_{1}$(theta) were deduced and the angular distribution of the azimuthal asymmetry factor \ensuremath{\Sigma}(theta)=${I}_{1}$(theta)/${I}_{0}$(theta) was obtained. An extensive comparison with theory has been carried out and the inclusion of corrections due to meson exchange currents and to \ensuremath{\Delta}-isobar configurations have been shown to be mandatory at energies ${E}_{\ensuremath{\gamma}}$\ensuremath{\gtrsim}40 MeV. Theoretical and experimental implications of intermediate energy deuteron photo- disintegration studies are discussed in some detail.

The total cross-section for the3He(γ, p)d reaction has been measured at γ-ray energy 48.6MeV with the monochromatic LADON photon beam and a nearly 4π proton detector.

The asymmetries ..sigma..(theta/sub c.m./ = ..pi../2) for the /sup 2/H(..gamma..,n)p reaction have been measured with use of the monochromatic and linearly polarized ..gamma..-ray beam (LADON), obtained by backward Compton scattering of laser light against high-energy electrons. Contributions from meson exchange currents must be included in the theoretical calculations to reproduce our data.