The Fermi Large Area Telescope

The Large Area Telescope, the primary instrument on the Fermi Gamma-ray Space Telescope, is an imaging, wide field-of-view gamma-ray telescope. After many improvements to the data acquisition and event analysis procedures, it now covers the broad energy range from $\sim 20$ MeV to $\sim 2$ TeV. After more than 13 years of operation since its launch in June 11, 2008, it has provided the best-resolved and deepest portrait of the gamma-ray sky. In this chapter we review the design of the instrument, the data acquisition system, calibration, and performance.Comment: 30 pages, 11 figures; Invited chapter for Handbook of X-ray and Gamma-ray Astrophysics (Eds. C. Bambi and A. Santangelo, Springer Singapore, expected in 2022

Perlindungan Hukum Bagi Penumpang Pesawat Udara Menurut Undang-undang No. 1 Tahun 2009 Tentang Penerbangan

Penelitian ini dilakukan dengan tujuan untuk mengetahui bagaimana pengaturan hukum terhadap penumpang pesawat udara dan bagaimana upaya perlindungan hukum saat mengalami kerugian pada kegiatan transportasi udara. Dengan menggunakan metode penelitian yuridis normatif dsimpulkan: 1. Dalam sistem hukum di Indonesia sudah terdapat beberapa peraturan di bidang transportasi udara di Indonesia, yaitu Undang-Undang No. 1 Tahun 2009 tentang Penerbangan, Peraturan Menteri Perhubungan No. PM 89 Tahun 2015 tentang Penanganan Keterlambatan Penerbangan (Delay Management) pada Badan Usaha Angkutan Udara Niaga Berjadwal di Indonesia, dan Peraturan Menteri Perhubungan No. 77 Tahun 2011 tentang Tanggung Jawab Pengangkut Angkutan Udara. Adapun dalam kegiatan transportasi udara perlu adanya perjanjian pengangkutan. Dengan adanya perjanjian pengangkutan, hak dan kewajiban para pihak yang terlibat di dalamnya dapat terjamin. 2. Dalam upaya perlindungan hukum saat mengalami kerugian pada kegiatan transportasi udara khususnya transportasi udara niaga, harus kita ketahui dulu bentuk-bentuk kerugian yang dapat dialami dalam kegiatan penerbangan yaitu keterlambatan, kehilangan dan kecelakaan baik yang menyebabkan luka-luka sampai kematian. Dengan meninjau bentuk-bentuk kerugian tersebut, maka ada beberapa aspek yang perlu diperhatikan sehubungan dengan pencegahan dan perlindungan konsumen bahkan semua pihak yang terlibat dalam transportasi udara, yaitu aspek keselamatan penerbangan, aspek kemanan penerbangan, aspek Kenyamanan selama penerbangan, aspek pelayanan, aspek penentuan tarif atau ongkos penerbangan, aspek perjanjian angkutan udara, aspek pengajuan klaim dan aspek perlindungan melalui asuransi. Kata kunci: Perlindungan hukum, penumpang, pesawat udar

Polyenes and vision

AbstractPolyenes are important for vision in all sighted species. The visual pigments (the rhodopsins) all use 11-cis-retinal as the chromophore; some possible reasons for the importance of this isomer are now emerging. New results on the involvement of xanthophils in the maintenance of the retina are also discussed

Strong Quasiparticle Trapping In A 6x6 Array Of Vanadium-Aluminum Superconducting Tunnel Junctions

A 6x6 array of symmetrical V/Al/AlOx/Al/V Superconducting Tunnel Junctions (STJs) was fabricated. The base electrode is a high quality epitaxial film with a residual resistance ratio (RRR) of ~30. The top film is polycrystalline with an RRR of ~10. The leakage currents of the 25x25 mm^2 junctions are of the order of 0.5 pA/mm^2 at a bias voltage of 100 mV, which corresponds to a dynamical resistance of ~ 3 10^5 ohms. When the array was illuminated by 6 keV X-ray photons from a 55Fe radioactive source the single photon charge output was found to be low and strongly dependent on the temperature of the devices. This temperature dependence at X-ray energies can be explained by the existence of a very large number of quasiparticle (QP) traps in the Vanadium. QPs are confined in these traps, having a lower energy gap than the surrounding material, and are therefore not available for tunneling. The number of traps can be derived from the energy dependence of the responsivity of the devices (charge output per electron volt of photon input energy).Comment: 4 pages. presented at Low Temperature Detectors-

First results of a cryogenic optical photon counting imaging spectrometer using a DROID array

Context. In this paper we present the first system test in which we demonstrate the concept of using an array of Distributed Read Out Imaging Devices (DROIDs) for optical photon detection. Aims. After the successful S-Cam 3 detector the next step in the development of a cryogenic optical photon counting imaging spectrometer under the S-Cam project is to increase the field of view using DROIDs. With this modification the field of view of the camera has been increased by a factor of 5 in area, while keeping the number of readout channels the same. Methods. The test has been performed using the flexible S-Cam 3 system and exchanging the 10x12 Superconducting Tunnel Junction array for a 3x20 DROID array. The extra data reduction needed with DROIDs is performed offline. Results. We show that, although the responsivity (number of tunnelled quasiparticles per unit of absorbed photon energy, e- /eV) of the current array is too low for direct astronomical applications, the imaging quality is already good enough for pattern detection, and will improve further with increasing responsivity. Conclusions. The obtained knowledge can be used to optimise the system for the use of DROIDs.Comment: 7 pages, 9 figures, accepted for publicaiton in A&

Novel technique for monitoring the performance of the LAT instrument on board the GLAST satellite

The Gamma-ray Large Area Space Telescope (GLAST) is an observatory designed to perform gamma-ray astronomy in the energy range 20 MeV to 300 GeV, with supporting measurements for gamma-ray bursts from 10 keV to 25 MeV. GLAST will be launched at the end of 2007, opening a new and important window on a wide variety of high energy astrophysical phenomena . The main instrument of GLAST is the Large Area Telescope (LAT), which provides break-through high-energy measurements using techniques typically used in particle detectors for collider experiments. The LAT consists of 16 identical towers in a four-by-four grid, each one containing a pair conversion tracker and a hodoscopic crystal calorimeter, all covered by a segmented plastic scintillator anti-coincidence shield. The scientific return of the instrument depends very much on how accurately we know its performance, and how well we can monitor it and correct potential problems promptly. We report on a novel technique that we are developing to help in the characterization and monitoring of LAT by using the power of classification trees to pinpoint in a short time potential problems in the recorded data. The same technique could also be used to evaluate the effect on the overall LAT performance produced by potential instrumental problems.Comment: 2 pages, 1 figure, manuscript submitted on behalf of the GLAST/LAT collaboration to First GLAST symposium proceeding

Sheep α-globin gene sequences: Implications for their concerted evolution and for the down-regulation of the 3' genes

In sheep as in man and most other mammals, there are two α-globin genes (Iα and IIα), which are expressed at different levels, the upstream gene being the most efficient. In α-globin gene triplication and quadruplication, this trend is confirmed, i.e., the α-chain output of the downstream genes progressively decreases. In this study, we have determined the complete sequence of the cDNAs and of both the introns in a triple-α haplotype in which each gene could be recognized for the presence of distinct alleles. The sequence analysis reveals that the bodies of the three α-globin genes are essentially identical (99.9% homology) and moreover indicates that the down-regulation of additional α-globin genes in sheep is not the effect of sequence variation from the Cap to the Poly(A) addition sites. This striking similarity among α-genes is higher than that seen in other mammals and is probably sustained by particularly efficient mechanisms of gene conversion and cross-over fixation