Capacity formulas in MWPC: some critical reflexions

An approximate analytical expression for "capacitance" of MWPC configurations circulates in the literature since decades and is copied over and over again. In this paper we will try to show that this formula corresponds to a physical quantity that is different from what it is usually thought to stand for

A comprehensive study of rate capability in Multi-Wire Proportional Chambers

Systematic measurements on the rate capability of thin MWPCs operated in Xenon, Argon and Neon mixtures using CO2 as UV-quencher are presented. A good agreement between data and existing models has been found, allowing us to present the rate capability of MWPCs in a comprehensive way and ultimately connect it with the mobilities of the drifting ions.Comment: 29 pages, 18 figure

Meningkatkan Hasil Belajar Siswa pada Pelajaran Ilmu Pengetahuan Alam di Kelas Vii-2 melalui Pendekatan Pembelajaran Cara Belajar Siswa Aktif di SMP Negeri 29 Medan

Tujuan penelitian untuk meningkatkan hasil belajar siswa pada pelajaran Ilmu Pengetahuan Alam di Kelas VII-2 melalui pendekatan pembelajaran cara belajar siswa aktif di SMP Negeri 29 Medan Tahun Pelajaran 2016/2017. Metode penelitian yang digunakan dalam penelitian adalah Metode Penelitian Tindakan Kelas dengan menggunakan 2 siklus. Subjek penelitian ini adalah siswa Kelas VII-2 SMP Negeri 29 Medan sebanyak 36 orang. Instrumen pengumpulan data yang digunakan untuk memperoleh data dalam penelitian ini adalah menggunakan test, angket dan observasi. Teknik analisa data menggunakan perhitungan jumlah nilai yang diperoleh siswa dibagi jumlah nilai total dikalikan dengan seratus kemudian perhitungan data menggunakan pengelompokan nilai rata-rata siswa, persentase siswa yang tuntas dan persentase jumlah siswa yang belum tuntas. Hasil Penelitian menunjukkan terdapat peningkatan hasil belajar dengan menerapkan pendekatan pembelajaran cara belajar siswa aktif dengan hasil sebagai berikut: (1) terdapat peningkatan rata-rata hasil belajar siswa, dimana pada tes awal rata-rata hasil belajar siswa adalah 41,67, pada siklus I meningkatkan menjadi 61,67 kemudian pada siklus II meningkat lagi menjadi 77,5, terdapat peningkatan jumlah siswa yang tuntas, dimana pada tes awal jumlah siswa yang tuntas hanya 0%, meningkat menjadi 52,78% pada siklus I kemudian meningkat lagi menjadi 86,11% pada siklus II, terdapat penurunan jumlah siswa yang tidak tuntas, dimana pada tes awal jumlah siswa yang tidak tuntas mencapai 100%, pada siklus I menurun menjadi 47,22% kemudian pada siklus II menurun lagi menjadi 13,89% dengan kata lain hanya 5 siswa saja yang memperoleh nilai 60 dan selebihnya (31) siswa memperoleh nilai di atas 70

Naturalistic Hydroseeding

The applications usually want to restore an adequate level of vegetation cover, to contrast effectively erosion and slope instability, however, often neglecting the naturalistic appearance. Really we should combine the technical aspect with the naturalistic, aiming to eliminate non-native species from vegetation context and to guide the choice of usable herbaceous species. The study, carried out in a dump of a southern Italian town (Termini Imerese - Sicily), provided for the reconstitution of plant cover of 7.4 hectares through hydroseeding applied directly on the soil of the final covering, with waste often exposed. The aim of this study was the use of alternative hydroseeding with the use of native plants for the recovery of the vegetation cover and increase the biodiversity of the intervention zone. So have been selected 21 species with high biotechnical value: Graminaceae species (genus: Ampelodesmos, Oryzopsis, Cynodon, Festuca , Brachipodium, Lolium, Lygeum) and Leguminosae species (genus: Hedysarum, Lotus, Medicago). In addition, were used seeds of wild flowers, fertilizers, mulch of wood fiber and cellulose, organic and synthetic adhesives. Moreover, a search was conducted on the morphology and resistance to tensile efforts of the roots of three species of referring: Ampelodesmos mauritanicus (Poir.) Dur. & Schinz, Oryzopsis miliacea (L.) Asch. & Schweinf and Hedysarum coronarium L. The first results confirm that the natural hydroseeding with native plants creates an effective plant cover in deprived areas; it also helps increase biodiversity. Therefore, the methodology used appears to be a more sustainable alternative to traditional hydroseeding using a mixture of commercial seeds and nationality is in doubt. The validity of the approach is also confirmed by the good results of biotechnical reference species both in terms of speed of growth, that of radical density (RAR) and the tension breaking roots

Solving the Bethe-Salpeter equation for a pseudoscalar meson in Minkowski space

A new method of solution of the Bethe-Salpeter equation for a pseudoscalar quark-antiquark bound state is proposed. With the help of an integral representation, the results are directly obtained in Minkowski space. Dressing of Green's functions is naturally taken into account, thus providing the possible inclusion of a running coupling constant as well as quark propagators. First numerical results are presented for a simplified ladder approximation

Charge Transfer and Charge Broadening of GEM Structures in High Magnetic Fields

We report on measurements of charge transfer in GEM structures in high magnetic fields. These were performed in the framework of the R&D work for a Time Projection Chamber at a future Linear Collider. A small test chamber has been installed into the aperture of a superconducting magnet with the GEM structures mounted perpendicular to the B field direction. The charge transfer is derived from the electrical currents monitored during irradiation with an ${}^{55}$Fe source. No severe loss of primary ionisation charge is observed, but an improved ion feedback suppression is achieved for high magnetic fields. Additionally, the width of the charge cloud released by individual ${}^{55}$Fe photons is measured using a finely segmented strip readout after the triple GEM structure. Charge widths between 0.3 and 0.5 mm RMS are observed, which originate from the charge broadening inside the GEM readout. This charge broadening is only partly suppressed at high magnetic fields.Comment: 11 pages, 9 figure

Development of Thick-foil and Fine-pitch GEMs with a Laser Etching Technique

We have produced thick-foil and fine-pitch gas electron multipliers (GEMs) using a laser etching technique. To improve production yield we have employed a new material, Liquid Crystal Polymer, instead of polyimide as an insulator layer. The effective gain of the thick-foil GEM with a hole pitch of 140 um, a hole diameter of 70 um, and a thickness of 100 um reached a value of 10^4 at an applied voltage of 720 V. The measured effective gain of the thick-foil and fine-pitch GEM (80 um pitch, 40 um diameter, and 100 um thick) was similar to that of the thick-foil GEM. The gain stability was measured for the thick-foil and fine-pitch GEM, showing no significant increase or decrease as a function of elapsed time from applying the high voltage. The gain stability over 3 h of operation was about 0.5%. Gain mapping across the GEM showed a good uniformity with a standard deviation of about 4%. The distribution of hole diameters across the GEM was homogeneous with a standard deviation of about 3%. There was no clear correlation between the gain and hole diameter maps.Comment: 21 pages, 9 figure

Development of a fast proton range radiography system for quality assurance in hadrontherapy

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