Double-sided Microstrip Research Articles

PAMELA: a satellite experiment for antiparticles measurement in cosmic rays

PAMELA is a satellite-borne experiment that will study the antiproton and positron fluxes in cosmic rays in a wide range of energy (from 80 MeV up to 190 GeV for antiprotons and from 50 MeV up to 270 GeV for positrons) and with high statistics, and that will measure the antihelium/helium ratio with a sensitivity of the order of 10/sup -8/. The detector will fly on-board a polar orbiting Resurs DK1 satellite, which will be launched into space by a Soyuz rocket in 2004 from Baikonur cosmodrome in Kazakhstan, for a 3-year-long mission. Particle identification and energy measurements are performed in the PAMELA apparatus using the following subdetectors: a magnetic spectrometer made up of a permanent magnet equipped with double-sided microstrip silicon detectors, an electromagnetic imaging calorimeter composed of layers of tungsten absorber and silicon detectors planes, a transition radiation detector made of straw tubes interleaved with carbon fiber radiators, a plastic scintillator time-of-flight and trigger system, a set of anticounter plastic scintillator detectors, and a neutron detector. The features of the detectors and the main results obtained in beam test sessions are presented.

The Silicon Tracker of the AMS02 experiment

After the successful test flight in 1998, the AMS experiment has been redesigned to improve its performances for future operation on the ISS. The Silicon Tracker is the central detector of the AMS-02 magnetic spectrometer. Eight planes of double-sided microstrip detectors embedded in a magnetic field of ∼0.8 T allow for an accurate 3D reconstruction of particles trajectories and their rigidity measurement up to several TVs. The tracker is made of ∼6.4 m 2 of silicon with a single point resolution of 10(30) μm in the bending (not bending) coordinate. The description of the tracker system and its performance will be presented.

Backward directional coupler for weak coupling of double-sided microstrip lines using longitudinal double-slots

A backward directional coupler for double-sided microstrip lines is presented. Aligned microstrip lines are coupled via two parallel slots in the common ground plane. This design works well for weak coupling smaller than 20 dB and has some advantages over the single-slot coupler. Geometrical dimensions of the proposed coupler design are presented for coupling values of 20, 25 and 30 dB, together with measurements for a 30 dB coupler.

Observation of substrate-type inversion in high-resistivity silicon structures irradiated with high-energy electrons

Several silicon devices, including test structures and double-sided microstrip detectors, have been irradiated with a 900 MeV electron beam. The irradiated test structures have been used to quantify bulk and surface damage effects caused by the incident particles. Bulk-type conversion from n to p-type has been observed to occur at fluences of order 10/sup 14/ cm/sup -2/. For the damage constant /spl alpha/, a NIEL normalized value of about 3/spl times/10/sup -17/ A/cm has been obtained. The results confirm that high-energy electrons, like neutrons and protons, are very effective in creating bulk damage in silicon.

Timing in thick silicon detectors for a Compton camera

In the scope of construction of a PET apparatus based on detection of Compton scattering in silicon (Compton camera), the timing properties of 1-mm-thick silicon pad and double-sided microstrip, detectors are studied. Timing in pad detectors is also investigated for 140.5 keV /sup 99m/Tc and 364.5 keV /sup 131/I gamma rays in view of a SPECT application. Compton scattering and energy loss of the Compton electron in the silicon detector are simulated using the GEANT package. The electric field in the detector is calculated numerically for a fully depleted detector in the abrupt junction approximation, taking into account the geometry and varying the reverse voltage. Signal formation is studied using Ramo's theorem and pulse shaping properties of the trigger circuit. A time-walk cut is seen to be directly corresponding to a deposited-energy cut. At 10 keV threshold in 1-mm-thick detectors, 10 ns timing windows are shown to reject a significant portion of events, degrading efficiency or limiting the angular range in a prohibitive way. More involved techniques are therefore suggested, either in the electronics circuit or in later stages of the trigger.

High performance double‐sided microstrip PBG filter

AbstractMicrowave filters in microstrip technology have been designed by taking advantage of metal patterning of the front and back‐side planes. It is shown that such an approach with drilled holes in the ground plane for the high impedance sections permits one to alleviate some of the drawbacks associated with uniplanar impedance modulated filters with high geometric aspect ratios. Prototypes for the S and C‐bands were fabricated by conventional low‐cost printed circuit techniques and show improved performances in terms of rejection and bandwidth. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 35: 90–93, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10525

Radiation damage of silicon structures with electrons of [formula omitted

We present first results on the irradiation of double-sided silicon microstrip detectors and test structures performed at the Elettra synchrotron radiation facility at Trieste, Italy. The devices were irradiated with 900 MeV electrons. The test structures we used for studying bulk, surface and oxide irradiation damage were guard ring diodes, gated diodes and MOS capacitors. The test structures and the double-sided microstrip detectors were produced by Micron Semiconductor Ltd. (England) and IRST (Trento, Italy). For the first time, bulk-type inversion is observed to occur after high-energy electron irradiation. Current and inter-strip resistance measurements performed on the microstrip detectors show that the devices are still usable after type inversion.

Low-noise front-end amplifier and channel encoder for a 2-D X-ray digital imaging system with single photon counting capability

We describe two VLSI CMOS ICs for 2-D X-ray digital imaging systems with single photon counting capability: a low noise front-end analog amplifier and an 80 MHz synchronous digital encoder. Our VLSI system will be optimized to perform X–Y coincidences with double-sided microstrip digital detector. The main application we are investigating is stereotaxic mammography, because of low X-ray energy used and the small area involved.

Double-sided microstrip detectors for the high radiation environment in the HERA-B experiment

The design of the double-sided microstrip detectors for the HERA-B experiment at DESY is discussed, in particular with respect to the strong requirements imposed by the high radiation environment and by the challenging mechanical construction. The detectors are tested with an infrared laser setup and first results from operation in the experiment in 1997 are presented.

A VLSI front-end circuit for microstrip silicon detectors for medical imaging applications

Abstract An analog CMOS-Integrated Circuit has been developed as Front-End for a double-sided microstrip silicon detector. The IC processes and discriminates signals in the 5–30 keV energy range. Main features are low noise and precise timing information. Low noise is achieved by optimizing the cascoded integrator with the 8 pF detector capacitance and by using an inherently low noise 1.2 μ m CMOS technology. Timing information is provided by a double discriminator architecture. The output of the circuit is a digital pulse. The leading edge is determined by a fixed threshold discriminator, while the trailing edge is provided by a zero crossing discriminator. In this paper we first describe the architecture of the Front-End chip. We then present the performance of the chip prototype in terms of noise, minimum discrimination threshold and time resolution.

Feasibility study for double-sided silicon microstrip detector fabrication at IRST

Abstract This paper is concerned with the preliminary results of a technological study aimed at the development of a fabrication process for double-sided AC-coupled silicon microstrip detectors. The approach adopted for the fabrication of both single-sided and double-sided detectors is presented, and the results from electrical tests performed on detectors and test structures are reported and discussed. Good electrical characteristics as well as an acceptable number of process-related defects have been obtained for these prototype detectors, thus demonstrating the feasibility of fabricating such devices at the IRST facility.

Ku-band double-sided suspended substrate microstrip coupled-line bandpass filter

A Ku-band double-sided suspended substrate microstrip (DSSSM) coupled-line bandpass filter with less than 2 dB insertion loss is presented. The design utilises five sections and is specified to be centred at 15 GHz with a moderate 10% bandwidth which is fabricated on an alumina substrate (ɛr = 9.9, h = 0.381 mm and airgap = 0.381 mm). The versatile configuration of the DSSSM provides a significant size reduction with easily realisable bandwidths due to a wider range of couplings obtainable from the overlapping (nonoverlapping) sections as compared to conventional suspended substrate microstrip.

The CDF silicon detector upgrade

A major silicon upgrade project is under way for the CDFII experiment that will operate during Run II of the Tevatron in the year 2000. The innermost detector, SVXII, will cover the interaction region with three barrels of five layers of double-sided microstrip detectors. In the radial gap between the SVXII and the new main tracking chamber (COT) will be located the ISL that consists of two planes of double-sided microstrip detectors at large pseudorapidity and one in the central region. A description of the project design and its motivation is presented here.

The ALPHA Magnetic Spectrometer

The ALPHA Magnetic Spectrometer (AMS) will be the first large magnetic spectrometer in space. It is scheduled to be installed on the future International Space Station ALPHA (ISSA) in the year 2002 to perform measurements of the charged particle composition to answer fundamental questions in particle physics and astrophysics. Before installation on ISSA, AMS will fly on the shuttle DISCOVERY for a period of 10 days starting in May 1998. This will enable AMS to perform a test of the apparatus and first measurements. The AMS detector has five major components: A permanent NdFeB magnet, six planes of Silicon double-sided microstrip detectors, a plastic scintillator time of flight hodoscope, a plastic scintillator anticoincidence counter and an Aerogel Cherenkov threshold counter. In addition, there are electronics, support infrastructure and interfaces.

Simple design formula of a slot-coupled directional coupler between double-sided microstrip lines

Simple design formula of a slot-coupled directional coupler between double-sided microstrip lines

A SPICE model of the ohmic side of double-sided Si microstrip detectors

We have developed a SPICE model for the ohmic side of AC-coupled Si microstrip detectors where interstrip isolation is obtained via field plates. The interstrip isolation has been measured in various conditions by varying the field plate voltage. Simulations have been compared with experimental data in order to determine the values of the SPICE parameters for different voltages applied to the field plates. The model is able to predict correctly the frequency dependence of the coupling between adjacent strips. Furthermore, we have used such model for the study of the signal propagation along the detector when a current signal is injected in a strip. Only electrical coupling is considered here, without any contribution due to charge sharing derived from carrier diffusion. For this purpose, the AC pads of the strips have been connected to a read-out electronics and the current signal has been injected into a DC pad. Good agreement between measurements and simulations has been reached for the central strip and the first neighbours. Experimental tests and computer simulations have been performed for four different strip and field plate layouts, in order to investigate how the detector geometry affects the parameters of the SPICE model and the signal propagation. Furthermore we have considered neutron irradiated devices to study the modifications induced by radiation on the detector performance and the impact on the SPICE model.

Characteristics of slot-coupled double-sided microstrip lines with various coupling slots

Effects of slot shapes and dimensions on the characteristics of slot-coupled double-sided microstrip lines are investigated. The slot length and end-loading effects are studied for a narrow rectangular coupling slot, and the case of a wide rectangular coupling slot is also analyzed. Results show that the end-loaded slots can improve the coupling between the double-sided microstrip lines. As for a narrow rectangular slot, optimal coupling can be obtained when the coupling slot is about at resonance, and the coupling increases when the slot width increases. Details of the results are presented and discussed. © 1996 John Wiley & Sons, Inc.

Studies of slot-coupled double-sided perpendicular microstrip lines

The double-sided perpendicular microstrip lines coupled through an arbitrarily inclined narrow rectangular slot in the common ground plane are studied by applying the reciprocity theorem and by using the exact Green's functions for the structure in a moment-method calculation for the unknown slot electric fields. The S parameters of the slot-coupled perpendicular microstrip lines are formulated and calculated, and theoretical results are verified with measurements. The effects of the inclination angle and length of the coupling slot on the electromagnetic coupling between the slot-coupled perpendicular microstrip lines are also studied. © 1996 John Wiley & Sons, Inc.

Analysis of slot-coupled double-sided cylindrical microstrip lines

The problem of double-sided cylindrical microstrip lines coupled through a rectangular slot in the common cylindrical ground plane is studied using the reciprocity theorem and a moment-method calculation. Theoretical results of the S-parameters for the slot-coupled cylindrical microstrip lines are calculated and analyzed. Experiments are also conducted to verify the theoretical results.

Radiation damage studies on single-sided and double-sided silicon microstrip detectors

The RD20 collaboration is investigating the operation of silicon microstrips as part of an inner tracking system at the LHC, an environment which requires both high speed readout and good radiation tolerance. We present measurements from both single-sided and double-sided microstrip test devices after neutron, proton, and photon irradiation up to fluences of 10 14 particles/cm 2 and doses of 10 Mrad. The double-sided microstrips include both field plate and p-stop isolation techniques. Important results include temperature dependence of long term irradiation-induced doping changes, strip isolation performance, and strip capacitance measurements.