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13 results on '"Kalavakuru, P."'

1. A Novel Wideband and Wide Beam High Gain Unidirectional Dipole Antenna for Next Generation WLAN Applications

Author

Kalavakuru, Sivadeep R., Gandji, Navid P., and Cyphert, Jonathan P.

Subjects
Computer Science - Networking and Internet Architecture
Abstract

In this paper, a novel wideband and widebeam unidirectional magneto-electric (ME) dipole antenna for Wi-Fi-7 (5.18-7.125GHz) applications is presented. The element is printed on low-cost substrate and is showing wide-band characteristics with impedance matching over 50% of fractional bandwidth. A tilted ME antenna with a tilted parasitic scatterer is radiating across wide frequency, while meeting over 100{\deg} angular width in both E-plane and H-plane across the wide bandwidth from 5GHz to >8GHz. Adding one parasitic scatterer on each side of dipole, broaden bandwidth of the antenna as well.

Published
2024

3. First functionality tests of a 64 x 64 pixel DSSC sensor module connected to the complete ladder readout

Author

Donato, Mattia, Hansen, Karsten, Kalavakuru, Pradeep, Kirchgessner, Manfred, Kuster, Markus, Porro, Matteo, Reckleben, Christian, and Turcato, Monica

Subjects
Physics - Instrumentation and Detectors
Abstract

The European X-ray Free Electron Laser (XFEL.EU) will provide every 0.1 s a train of 2700 spatially coherent ultrashort X-ray pulses at 4.5 MHz repetition rate. The Small Quantum Systems (SQS) instrument and the Spectroscopy and Coherent Scattering instrument (SCS) operate with soft X-rays between 0.5 keV - 6keV. The DEPFET Sensor with Signal Compression (DSSC) detector is being developed to meet the requirements set by these two XFEL.EU instruments. The DSSC imager is a 1 mega-pixel camera able to store up to 800 single-pulse images per train. The so-called ladder is the basic unit of the DSSC detector. It is the single unit out of sixteen identical-units composing the DSSC-megapixel camera, containing all representative electronic components of the full-size system and allows testing the full electronic chain. Each DSSC ladder has a focal plane sensor with 128 x 512 pixels. The read-out ASIC provides full-parallel readout of the sensor pixels. Every read-out channel contains an amplifier and an analog filter, an up-to 9 bit ADC and the digital memory. The ASIC amplifier have a double front-end to allow one to use either DEPFET sensors or Mini-SDD sensors. In the first case, the signal compression is a characteristic intrinsic of the sensor; in the second case, the compression is implemented at the first amplification stage. The goal of signal compression is to meet the requirement of single-photon detection capability and wide dynamic range. We present the first results of measurements obtained using a 64 x 64 pixel DEPFET sensor attached to the full final electronic and data-acquisition chain., Comment: Preprint proceeding for IWORID 2016, 18th International Workshop on Radiation Imaging Detectors, 3rd-7th July 2016, Barcelona, Spain

Published
2017
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5. The MiniSDD-Based 1-Mpixel Camera of the DSSC Project for the European XFEL

Author

Porro, M., Andricek, L., Aschauer, S., Castoldi, A., Donato, M., Engelke, J., Erdinger, F., Fiorini, C., Fischer, P., Graafsma, Heinz, Grande, A., Guazzoni, C., Hansen, K., Hauf, S., Kalavakuru, P., Klaer, H., Tangl, M., Kugel, A., Kuster, M., Lechner, P., Lomidze, D., Maffessanti, S., Manghisoni, M., Nidhi, S., Okrent, F., Re, V., Reckleben, C., Riceputi, E., Richter, R., Samartsev, A., Schlee, S., Soldat, J., Struder, L., Szymanski, J., Turcato, M., Weidenspointner, G., Wunderer, C. B., Porro, M., Andricek, L., Aschauer, S., Castoldi, A., Donato, M., Engelke, J., Erdinger, F., Fiorini, C., Fischer, P., Graafsma, Heinz, Grande, A., Guazzoni, C., Hansen, K., Hauf, S., Kalavakuru, P., Klaer, H., Tangl, M., Kugel, A., Kuster, M., Lechner, P., Lomidze, D., Maffessanti, S., Manghisoni, M., Nidhi, S., Okrent, F., Re, V., Reckleben, C., Riceputi, E., Richter, R., Samartsev, A., Schlee, S., Soldat, J., Struder, L., Szymanski, J., Turcato, M., Weidenspointner, G., and Wunderer, C. B.

Abstract

The first DSSC 1-Mpixel camera became available at the European XFEL (EuXFEL) in the Hamburg area in February 2019. It was successfully tested, installed, and commissioned at the Spectroscopy and Coherent Scattering Instrument. DSSC is a high-speed, large-area, 2-D imaging detector system optimized for photon science applications in the energy range between 0.25 and 6 keV. The camera is based on direct conversion Si sensors and is composed of 1024 × 1024 pixels of hexagonal shape with a side length of 136∼μm. The 256 application-specific integrated circuits (ASICs) provide full parallel readout, comprising analog filtering, digitization, and in-pixel data storage. In order to cope with the demanding X-ray pulse time structure of the EuXFEL, the DSSC provides a peak frame rate of 4.5 MHz. The first Mpixel camera is equipped with miniaturized silicon drift detector (MiniSDD) pixel arrays. The intrinsic response of the pixels and the linear readout limit the dynamic range but allow one to achieve noise values of about 60 electrons r.m.s. at the highest frame rate. The challenge of providing high-dynamic range (104 photons/pixel/pulse) and single-photon detection simultaneously requires a nonlinear system front end, which will be obtained with the DEPFET active pixel technology foreseen for the advanced version of the camera. This technology will provide lower noise and a nonlinear response at the sensor level. This article describes the architecture of the whole detector system together with the main experimental results achieved up to now. © 1963-2012 IEEE., Export Date: 20 September 2021; Article; CODEN: IETNA

Published
2021
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6. Qualification and integration aspects of the DSSC mega-pixel X-ray imager

Author

Hansen, K., Klar, H., Kalavakuru, P., Reckleben, C., Venzmer, A., Wustenhagen, E., Schappeit, R., Zeides, O. -C., Okrent, F., Wunderer, C., Lemke, M., Graafsma, H., Schlosser, I., Manghisoni, M., Riceputi, E., Aschauer, S., Struder, L., Soldat, J., Tangl, M., Erdinger, F., Kugel, A., Fischer, P., Andricek, L., Ninkovic, J., Turcato, M., and Porro, M.

Subjects
Adhesive strength, assembly, circuit testing, hybrid integrated circuits, image sensor, metrology, packaging technology, X-ray detector, ddc:620, Settore ING-INF/01 - Elettronica
Abstract

IEEE transactions on nuclear science 66(8), 1966 - 1975 (2019). doi:10.1109/TNS.2019.2927421, The focal-plane module is the key component of the DEPFET sensor with signal compression (DSSC) mega-pixel X-ray imager and handles the data of 128 $\times512$ pixels. We report on assembly-related aspects, discuss the experimental investigation of bonding behavior of different adhesives, and present the metrology and electrical test results of the production. The module consists of two silicon (Si) sensors with flip-chip connected CMOS integrated circuits, a Si-heat spreader, a low-temperature co-fired ceramics circuit board, and a molybdenum frame. A low-modulus urethane-film adhesive fills the gaps between on-board components and frame. It is also used between board and heat spreader, reduces the misfit strain, and minimizes the module warpage very efficiently. The heat spreader reduces the on-board temperature gradient by about one order of magnitude. The placement precision of the bare modules to each other and the frame is characterized by a standard deviation below 10 and 65 $\mu \text{m}$ , respectively. The displacement due to the in-plane rotation and vertical tilting errors remains below 80 and 50 $\mu \text{m}$ , respectively. The deflection of the sensor plane shows a mean value below 30 $\mu \text{m}$ with a standard deviation below 15 $\mu \text{m}$ . Less than 4% of the application-specified integrated circuits (ASICs) exhibit a malfunction. More than two-thirds of the sensors have a maximum leakage current below 1 $\mu \text{A}$ ., Published by IEEE, New York, NY

Published
2019
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7. Qualification and Integration Aspects of the DSSC Mega-Pixel X-Ray Imager

Author

Hansen, K., primary, Klar, H., additional, Kalavakuru, P., additional, Reckleben, C., additional, Venzmer, A., additional, Wustenhagen, E., additional, Schappeit, R., additional, Zeides, O.-C., additional, Okrent, F., additional, Wunderer, C., additional, Lemke, M., additional, Graafsma, H., additional, Schlosser, I., additional, Manghisoni, M., additional, Riceputi, E., additional, Aschauer, S., additional, Struder, L., additional, Soldat, J., additional, Tangl, M., additional, Erdinger, F., additional, Kugel, A., additional, Fischer, P., additional, Andricek, L., additional, Ninkovic, J., additional, Turcato, M., additional, and Porro, M., additional

Published
2019
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10. Pixel Readout ASIC with per Pixel Digitization and Digital Storage for the DSSC Detector at XFEL

Author

Fischer, P., Bach, M., Bombelli, Luca, Citterio, M., Erdinger, F., Facchinetti, Stefano, Fiorini, CARLO ETTORE, Hansen, K., Kalavakuru, P., Manghisoni, M., Porro, Matteo, Quartieri, E., Reckleben, C., and de Vita, G.

Subjects
Physics, sezele, Pixel, Serial communication, business.industry, XFEL, Detector, Electrical engineering, Signal compression, pixel detector, readout electronics, DEPFET, synchrotron radiation detector, Semiconductor memory, Chip, Settore ING-INF/01 - Elettronica, Application-specific integrated circuit, Nuclear electronics, Hardware_INTEGRATEDCIRCUITS, Optoelectronics, business
Abstract

The DSSC collaboration is developing an instrument for the detection of synchrotron X-rays (E > 0.5 keV) at XFEL. The hexagonal pixels of a DEPFET based sensor with integrated signal compression will be read out by bump-bonded pixel readout ASICs. Each ASIC will have 64 × 64 pixel channels of 236 × 204 μm2 area, each one containing a low-noise ( 512 events capacity. The accumulated digital data is transferred off chip during the 100 ms long burst gaps on a single serial link while the analogue sections are shut down to bring the average power dissipation to < 100 mW per ASIC. The chip architecture is described and results obtained from first test chips are presented.

Published
2010

11. Development of the DEPFET Sensor With Signal Compression: A Large Format X-Ray Imager With Mega-Frame Readout Capability for the European XFEL

Author

Porro, M., primary, Andricek, L., additional, Aschauer, S., additional, Bayer, M., additional, Becker, J., additional, Bombelli, L., additional, Castoldi, A., additional, De Vita, G., additional, Diehl, I., additional, Erdinger, F., additional, Facchinetti, S., additional, Fiorini, C., additional, Fischer, P., additional, Gerlach, T., additional, Graafsma, H., additional, Guazzoni, C., additional, Hansen, K., additional, Kalavakuru, P., additional, Klar, H., additional, Kugel, A., additional, Lechner, P., additional, Lemke, M., additional, Lutz, G., additional, Manghisoni, M., additional, Mezza, D., additional, Muntefering, D., additional, Pietsch, U., additional, Quartieri, E., additional, Randall, M., additional, Re, V., additional, Reckleben, C., additional, Sandow, C., additional, Soldat, J., additional, Struder, L., additional, Szymanski, J., additional, Weidenspointner, G., additional, and Wunderer, C. B., additional

Published
2012
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