AC-coupled Silicon Microstrip Detectors Research Articles

Radiation damage studies for the B aB ar Silicon Vertex Tracker

The Silicon Vertex Tracker of the B aB ar experiment is a five-layer, double-sided AC-coupled silicon microstrip detector operating on the PEP-II storage ring at the Stanford Linear Accelerator Center. After more than four years of running, the silicon sensors and the front-end electronics in the inner layer have absorbed radiation doses up to 2 Mrad. In this paper we present results from radiation hardness tests and discuss the implications of the absorbed radiation dose on the Silicon Vertex Tracker lifetime.

Lessons learned from the BaBar Silicon Vertex Tracker

The Silicon Vertex Tracker (SVT) of the BABAR experiment at the PEP-II asymmetric B factory consists of a five-layer double sided, AC coupled silicon microstrip detector. It represents a key element to measure with precision the decay position of B mesons, satisfying the severe constraints imposed by the accelerator design, in terms of geometry of the interaction region and conditions of operation. In the following paper, a critical review of the SVT general design and performance is made, with special attention to those details of the design and the assembly procedure that are considered a source of possible problems given the experience accumulated during the construction, the commissioning and the first 5 years of operation.

The BaBar Silicon Vertex Tracker: performance and radiation damage studies

The BaBar Silicon Vertex Tracker is a five layers, double sided AC-coupled silicon microstrip detector operating on the PEP-II storage ring at the Stanford Linear Accelerator Center. The performance of the SVT after 4 years of running is described. Results from radiation hardness tests are presented and the implications of the absorbed radiation dose on the SVT lifetime are discussed.

Performance of the BABAR silicon vertex tracker

The Silicon Vertex Tracker (SVT) of the BABAR experiment at the PEP-II asymmetric B factory is a five layer double sided, AC coupled silicon microstrip detector. It represents the crucial element to precisely measure the decay position of B mesons . The SVT architecture is shown and its performances, like hit resolutions and efficiencies, are described. Radiation issues are discussed and the alignment procedure for the SVT is described. As an example for the physics performance the B lifetime measurement, including B vertex reconstruction, is shown.

The BaBar silicon-vertex tracker: performance, running experience, and radiation-damage studies

The silicon-vertex tracker (SVT) for the BaBar Experiment at the PEP-H Asymmetric B Factory at Stanford Linear Accelerator Center (SLAC), is a five-layer double-sided ac-coupled silicon-microstrip detector. It is a crucial element for the precise measurement of the decay position of B mesons, satisfying the severe constraints imposed by the accelerator design, in terms of geometry of the interaction region and conditions of operation. In the following paper, the SVT performance is described. Radiation issues are discussed and the results of different tests aimed to study the decrease in the SVT performance due to radiation damage are presented. The alignment procedure is described, and a few BaBar physics results are presented as examples of the SVT capabilities to reconstruct decay vertices with good resolution and efficiency.

The BaBar silicon vertex tracker, performance and running experience

The Silicon Vertex Tracker (SVT) of the BaBar experiment at the PEP-II asymmetric B factory is a five-layer double-sided, AC-coupled silicon microstrip detector. It represents the crucial element to precisely measure the decay position of B mesons and extract time-dependent CP asymmetries. The SVT architecture is shown and its performance is described, with emphasis on hit resolutions and efficiencies.

Development of a fabrication technology for double-sided AC-coupled silicon microstrip detectors

We report on the development of a fabrication technology for double-sided, AC-coupled silicon microstrip detectors for tracking applications. Two batches of detectors with good electrical figures and a low defect rate were successfully manufactured at IRST Laboratory. The processing techniques and the experimental results obtained from these detector prototypes are presented and discussed.

Physical modeling of silicon microstrip detectors: influence of the electrode geometry on critical electric fields

In this paper, a computer-based analysis of AC-coupled silicon microstrip detectors is presented. The study aims at investigating the main geometrical parameters responsible for potentially critical effects, such as early micro-discharges and breakdown phenomena. The adoption of CAD tools allows for evaluating the actual field distribution within the device, and makes it possible to identify critical regions. The adoption of overhanging metal strips is shown to have a positive impact on the electric field distribution, reducing corner effects and thus minimizing breakdown risks.

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.

The CLEO II.V silicon vertex detector

A description of the new silicon tracker installed in the CLEO interaction region is given. This device consists of three layers of double-sided AC-coupled silicon microstrip detectors arranged in an octagonal array. The wafers are readout by 416 CAMEX64/JAMEX64 VLSI amplifier chips. A description of the data acquisition and monitoring systems developed to read out the SVX is provided. A summary of performance and some results are presented.

Signal-to-noise in silicon microstrip detectors with binary readout

We report the results of a beam test at KEK using double-sided AC-coupled silicon microstrip detectors with binary readout, i.e., a readout where the signals are discriminated in the front-end electronics and only the hit location as kept. For strip pitch between 50/spl mu/ and 200/spl mu/, we determine the efficiency and the noise background as function of threshold setting. This allows us to reconstruct the Landau pulse height spectrum and determine the signal/noise ratio. In addition, the threshold/noise ratio necessary for operation with low occupancy is determined. >

Double-sided double-metal AC-coupled silicon microstrip detectors

Novel silicon microstrip detectors, which combine double side operation, on-chip coupling capacitors and two levels of metallization have been developed, manufactured and tested. This approach aims at very low mass system assemblies, particularly important for applications in vertex detection at LEP and at future B-factories. Devices were integrated on 100 mm diameter silicon wafers on which several dielectrics for AC coupling were tested. A SiO2Si3N4 double dielectric layer, etched between strips, performed best with respect to leakage current, breakdown voltage and oxide integrity. In order to minimize stray capacitance between strips in the 2 metal layers, an extremely thick (5.2 μm) intermetal dielectric layer was used. A special photolithographic and etching process which guarantees good step coverage was developed, resulting in tapered vias.Static measurements were carried out on detectors of various dimensions. Leakage current, depletion voltage and capacitive effects from cross-coupling between metal 1 and metal 2 were measured. In particular, the breakdown characteristics of the coupling capacitor formed by the implanted strips and the metal 1 strips were investigated for several insulators. With the SiO2Si3N4 double dielectric layer, a pinhole density of the order of 1% was obtained for some of the detectors, with leakage currents of around 100 nA/cm2. The connectivity between metal 1 and metal 2 layers was found to be excellent. The dynamic response of the detectors was studied using the VIKING front-end readout chip.The results show that these complex double-sided chips, which are required for next generation detectors, are reaching a state of maturity.

Analysis of capacitance measurements on silicon microstrip detectors

We present an analysis of the total strip capacitance of double-sided, AC-coupled silicon microstrip detectors. We evaluate the radiation hardness and the noise contribution of different strip geometries. We comment on a serious failure mode. >

Capacitances in silicon microstrip detectors

We present an analysis of the capacitances which are important for the operation of double-sided, AC-coupled silicon microstrip detectors. From frequency dependent measurements we extract interstrip, body and coupling capacitances of the strips, using SPICE simulations. Using electrostatic simulations we calculate the geometry dependence of interstrip and body capacitances and of depletion voltages. We evaluate the radiation hardness and the noise contribution of different strip geometries.

Progress in the construction of the delphi microvertex detector

The design and progress in the construction of the DELPHI microvertex detector are presented. The layout is described, together with results on precision mounting of silicon detectors. The development of ac-coupled silicon microstrip detectors was an important contribution to the design. The use of low-power CMOS readout chips facilitates the cooling of the detector. A description of the fourth-generation readout processor for silicon strip detectors, the SIROCCO IV, implemented in FASTBUS, is given. Finally, two complementary systems for in-situ position monitoring of the detectors are described.