Double-sided Silicon Detectors Research Articles

Quality Assurance Test System for Assembly of STS Modules for the BM@N Experiment

The Silicon Tracking System (STS) of the BM@N experiment will be based on modules with Double-Sided microstrip Silicon Detectors (DSSD) which have been initially developed for the CBM experiment at FAIR. Each module consists of a DSSD, two front-end boards with 8 ASICs each, and a set of low-mass aluminum microcables. During the module assembly the microcables are tab-bonded to the sensor and readout ASICs. The module has 1024 channels on each side of the sensor. For the quality assurance of the ultrasonic bonding process a dedicated procedure based on the noise per channel measurements with a Pogo Pin test device was developed.

Test Bench for Highly Segmented GRIT Double-Sided Silicon Strip Detectors: A Detector Quality Control Protocol

This work deals with the characteristics of highly segmented double-sided silicon detectors. These are fundamental parts in many new state-of-the-art particle detection systems, and therefore they must perform optimally. We propose a test bench that can handle 256 electronic channels with off-the-shelf equipment, as well as a detector quality control protocol to ensure that the detectors meet the requirements. Detectors with a large number of strips bring new technological challenges and issues that need to be carefully monitored and understood. One of the standard 500 μm thick detectors of the GRIT array was investigated, undergoing studies that revealed its IV curve, charge collection efficiency, and energy resolution. From the data obtained, we calculated, among other things, the depletion voltage (110 V), the resistivity of the bulk material (9 kΩ·cm), and the electronic noise contribution (8 keV). We present, for the first time, a methodology called “the energy triangle’’ to visualize the effect of charge sharing between two adjacent strips and to study the hit distribution with the interstrip-to-strip hit ratio (ISR).

Reorientation-effect measurement of the 〈21+∥Ê2∥21+〉 matrix element in Ar36

The spectroscopic quadrupole moment of the first excited 21+ state, QS(21+), at 1.970 MeV in Ar36 was determined at energies well below the Coulomb barrier—where nuclear interference effects are negligible—using the Pt194(Ar36,Ar*36)Pt*194 Coulomb-excitation reaction at 134.2 MeV. Particle-gamma coincidence data were collected using the AFRODITE array—composed of eight high-purity germanium clover detectors—and an upstream double-sided silicon detector at iThemba LABS. A large diagonal matrix element of 〈21+∥E2̂∥21+〉=0.163(42) eb was determined, which yields a more accurate value of QS(21+)=+0.12(3) eb as compared with previous work, QS(21+)=+0.11(6) eb, in agreement with modern beyond mean-field and large-scale shell-model calculations. This value is consistent with the ratio of electric quadrupole moments found for other A=4n self-conjugate nuclei extracted from the reorientation effect and the rotor model, which are surprisingly equivalent to those observed in good rotors in the mass A≈160–180 region.Received 22 September 2021Accepted 28 November 2021DOI:https://doi.org/10.1103/PhysRevC.104.L061305©2021 American Physical SocietyPhysics Subject Headings (PhySH)Research AreasCollective levelsCollective modelsElectromagnetic transitionsHydrodynamic modelsNuclear structure & decaysPhotonuclear reactionsShell modelSpectroscopic factors & electromagnetic momentsProperties20 ≤ A ≤ 38TechniquesRadiation detectorsNuclear Physics

Property investigation of the wedge-shaped CsI(Tl) crystals for a charged-particle telescope

Two types of wedge-shaped CsI(Tl) crystals were designed to be placed behind an annular double-sided silicon detector to identify light charged-particles with the ΔE−E method. The properties of the CsI(Tl) detectors with different shapes and sizes were investigated using an α source and a radioactive beam of 15C. The larger crystal was found to have better energy resolution, smaller light output non-uniformity, as well as better particle identification capability, and was finally adopted to form the ΔE-E telescope. The performance of the two types of CsI(Tl) crystals are interpreted based on Geant4 simulation results.

A β-delayed neutron detection system working with the continuous beam mode

Abstract To study the β -delayed neutron decay of nuclei far from β stability line, a new β -delayed neutron detection system working with the continuous beam mode has been built at Peking University and tested with radioactive ion beams . To get fast timing signal for neutron Time-of-Flight (ToF) measurement and good spatial correlation between the implanted particles and the subsequent β particles, a double-sided silicon detector is sandwiched between two thin plastic scintillators , which constitute the implantation and β detection array. According to the test measurements with radioactive ion beams, this detection system has a high β coincident detection efficiency of 30 . 7 ( 5 ) % with much less disturbance from other unstable nuclei and the random background. After the time-walk correction and the flight path calibration, good energy resolution based on neutron ToF measurement can be obtained. The properties of this detection system make the study of β -delayed neutron decay of nuclei with very low beam intensity feasible.

Investigation of the spontaneous fission properties of neutron-deficient nobelium isotopes

In the last years we carried out several experiments aimed to investigate properties of short-lived SF isotopes. The neutron-deficient isotopes of nobelium were produced in fusion-evaporation reactions using 206,208 Pb targets and an intense 48 Ca-beam. Fusion-evaporation residues were separated by the SHELS separator and implanted into a large-area double-sided (48 × 48) strip silicon detector surrounded by 3 He-based neutron counters. Half-lives and decay branching ratios for 252,254 No isotopes were measured. The average number of neutrons per spontaneous fission of 254 No determined for the first time.

The Belle II silicon vertex detector: Assembly and initial results

The “chip-on-sensor” concept of this detector minimizes the distance of the signal propagation from the double-sided silicon detector strips to the readout chips and thus reduces noise from strip capacitance. One half of the detector is built, the second half is being assembled at the time of writing. Prototypes have been tested in several test beams as well as in the so-called Phase 2 setup inside the detector structure. First results from a commissioning run of the Belle-II prototype SVD detector are presented. The measured signal-to-noise and timing performance are found to be according to design specifications.

Central tracker for BM@N experiment based on double side Si-microstrip detectors

Design of central tracker system based on Double-Sided Silicon Detectors (DSSD) for BM@N experiment is described. A coordinate plane with 10240 measuring channels, pitch adapter, reading electronics was developed. Each element was tested and assembled into a coordinate plane. The first tests of the plane with 106Ru source were carried out before installation for the BM@N experiment. The results of the study indicate that noisy channels and inefficient channels are less than 3%. In general, single clusters 87% (one group per module of consecutive strips) and 75% of clusters with a width equal to one strip.

Direct comparison between solid state Silicon+6LiF and 3He gas tube neutron detectors

During the last decade the worldwide lack of 3He for neutron detection has triggered research and development on alternative technologies and methods. One of the promising techniques consists of assembling sandwiches of fully depleted double sided Silicon detectors between thin layers of 6LiF neutron converter material. In this paper we show the very promising result of a comparative test of such a detector with respect to an elliptical section 3He filled proportional counter for application at spallation neutron source facilities.

An implantation and β detection system applied in β-decay studies

To study the β decays of nuclei far from the β-stability line, an implantation and β detection system has been implemented at the Peking University. This detection system covers a wide energy range from keV to GeV while maintaining a good energy resolution and a low detection threshold. By correlating the implantation nuclei with their subsequent β-decays within the same pixel or adjacent pixels of a double-sided silicon detector (DSSD), the β decay properties of implanted nuclei can be measured with much less disturbance from other unstable nuclei and the random background.

Interstrip effects influence on the particle identification of highly segmented silicon strip detector in a nuclear reaction scenario

Identification of the interstrip effects using digital pulse shape analysis is for the first time reported. This study is performed on a highly segmented double-sided silicon detector used in a nuclear reaction in which a large range of particles at different energies are produced. The output current pulse of the preamplifier is employed as observable. The interstrip effects diminish the capability of particle identification at energies below 5MeV, especially on the injection side of the detector.

Total and Partial Fragmentation Cross-Section of 500 MeV/nucleon Carbon Ions on Different Target Materials

By using an experimental setup based on thin and thick double-sided microstrip silicon detectors, it has been possible to identify the fragmentation products due to the interaction of very high energy primary ions on different targets. Here we report total and partial cross-sections measured at GSI (Gesellschaft fur Schwerionenforschung), Darmstadt, for 500 MeV/n energy $^{12}C$ beam incident on water (in flasks), polyethylene, lucite, silicon carbide, graphite, aluminium, copper, iron, tin, tantalum and lead targets. The results are compared to the predictions of GEANT4 (v4.9.4) and FLUKA (v11.2) Monte Carlo simulation programs.

Performance studies on the ohmic side of silicon microstrip sensors

High precision collider experiments at high energy accelerators and B-factories need accurate position resolution while preserving a low material budget for precise particle tracking. Thin double-sided silicon detectors (DSSDs) fulfill both requirements, if a careful sensor design is applied to maintain a high charge collection efficiency. In this continuation of a previous study we investigate the p-stop and the p-spray blocking methods for strip isolation on the n-side (ohmic side) of DSSDs with n-type bulk. We compare three different p-stop patterns: the common p-stop pattern, the atoll p-stop pattern and a combination of these patterns, and for every pattern four different geometric layouts are considered. Moreover we investigate the effect of the strip isolation on sensors with one intermediate strip. Sensors featuring these p-stop patterns and the p-spray blocking method were tested in a 120GeV/c hadron beam at the SPS at CERN, γ-irradiated to 100kGy at SCK-CEN (Mol, Belgium), and immediately afterwards tested again at CERN in the same setup as before. The results of these tests are used to optimize the design of DSSDs for the Belle II experiment at KEK (Tsukuba, Japan).

A Low Mass On-Chip Readout Scheme for Double-Sided Silicon Strip Detectors

B-factories like the KEKB in Tsukuba, Japan, operate at relatively low energies and thus require detectors with very low material budget in order to minimize multiple scattering. On the other hand, front-end chips with short shaping time like the APV25 have to be placed as close to the sensor strips as possible to reduce the capacitive load, which mainly determines the noise figure.In order to achieve both – minimal material budget and low noise – we developed a readout scheme for double-sided silicon detectors, where the APV25 chips are placed on a flexible circuit, which is glued onto the top side of the sensor. The bottom-side strips are connected by two flexible circuits, which are bent around the edge of the sensor.This so-called “Origami” design will be utilized to build the Silicon Vertex Detector of the Belle II experiment, which will consist of four layers made from ladders with up to five double-sided silicon strip sensors in a row. Each ladder will be supported by two ribs made of a carbon fiber and Airex foam core sandwich. The heat dissipated by the front-end chips will be removed by a highly efficient two-phase CO2 system. Thanks to the Origami concept, all APV25 chips are aligned in a row and thus can be cooled by a single thin cooling pipe per ladder.We present the concept and the assembly procedure of the Origami chip-on-sensor modules.

The Micro-Vertex-Detector for the P̄ANDA experiment

P̄ANDA is a fixed target experiment that will be carried out at the future FAIR facility. P̄ANDA will provide an excellent tool to address fundamental question in the field of hadronic physics, with a physic program that extends from the investigation of QCD (providing insight in the mechanisms of mass generation and confinement) to the test of fundamental symmetries.The Micro-Vertex-Detector located in the innermost part of the central tracking system will be composed by hybrid pixel and double-sided micro-strip silicon detectors. The Micro-Vertex-Detector will play an important role for the P̄ANDA physics goals. The possibility to reconstruct the secondary vertices and the applicability of a precise D meson tagging is essential for the spectroscopy in the open charm sector and the charmonium mass region. To this aim the Micro-Vertex-Detector features a spatial resolution better than 100μm, a time resolution better than 20ns, a limited material budget, and a high data rate capability in a triggerless environment. An overview of the Micro-Vertex-Detector related to the physics goals will be presented.

Comparison of n-side strip isolation methods for silicon sensors

Precision experiments at electron-positron-colliders and b-factories demand high position resolution and low material budget for precise particle tracking. These requirements are fulfilled by thin double-sided silicon detectors (DSSDs). However, due to the low signals of thin sensors a careful sensor design is required in order to achieve high charge collection efficiency. In this paper we investigate the p-stop and the p-spray blocking method for strip isolation on the n-side of DSSDs with n-type bulk. We compare three different p-stop patterns: the common p-stop, the atoll p-stop and a combined p-stop pattern, whereas for every pattern four different geometric layouts are considered. Test sensors featuring these p-stop patterns and the p-spray blocking method were tested in a 120 GeV/c hadron beam at the Super Proton Synchrotron (SPS) at CERN (Geneva, Switzerland), where one variant of the atoll p-stop pattern performed best. The results of these tests are used to design the DSSDs for the Belle II experiment at KEK (Tsukuba, Japan).

Optimization of Strip Isolation for Silicon Sensors

Abstract Precision machines like electron-positron-colliders and b-factories demand for low material budget and high position resolution when it comes to particle tracking. A low material budget can be achieved by using thin double-sided silicon detectors (DSSDs) and lightweight construction. Since thin sensors give low signals, one has to be very careful to achieve high charge collection efficiency, which requires an appropriate sensor design. In this paper we present a detailed investigation of different p-stop patterns used for strip isolation on the n-side of double-sided microstrip sensors with n-type bulk. We designed test sensors featuring the common p-stop, the atoll p-stop and a combined p-stop pattern, and for every pattern four different geometric layouts were considered. These sensors were tested at the Super Proton Synchrotron (SPS) at CERN (Geneva, Switzerland) in a 120 GeV/c hadron beam. Then they were irradiated to 700 kGy with a 60 Co source and subsequently tested in the same beam as before. One geometric layout of the atoll p-stop pattern turned out to perform best, both before and after irradiation. The conclusions of these tests will be applied to the design of DSSDs for the Belle II experiment at KEK (Tsukuba, Japan).

连续束模式下β衰变研究的实验装置

To study the beta decay of nuclei far from the beta-stable valley, a new implantation and beta detection system has been developed at the Peking University. Working with the logarithmic MPR-16 preamplifier, this detection system covers a large energy range from keV to GeV with good energy resolution and stability. By correlating the implantation nuclei with their subsequent beta decays within the same pixel of a double-sided silicon detector (DSSD), we can measure the decay time of the implantation nuclei with much less disturbance from the neighboring unstable nuclei and background.

Electronics and mechanics for the Silicon Vertex Detector of the Belle II experiment

A major upgrade of the KEK-B factory (Tsukuba, Japan), aiming at a peak luminosity of 8 × 1035cm−2s−1, which is 40 times the present value, is foreseen until 2014. Consequently an upgrade of the Belle detector and in particular its Silicon Vertex Detector (SVD) is required. We will introduce the concept and prototypes of the full readout chain of the Belle II SVD. Its APV25 based front-end utilizes the Origami chip-on-sensor concept, while the back-end VME system provides online data processing as well as hit time finding using FPGAs. Furthermore, the design of the double-sided silicon detectors and the mechanics will be discussed.

Characterization of Silicon Detectors for the SiliPET Project: A Small Animal PET Scanner Based on Stacks of Silicon Detectors

In this paper we propose a new scanner for small animal positron emission tomography (PET) based on stacks of double sided silicon detectors. Each stack is composed of 40 planar detectors with dimension 60 mm x 60 mm x 1 mm and 128 orthogonal strips on both sides to read the two coordinates of interaction, the third being the detector number in the stack. Multiple interactions in a stack are discarded. In this way we achieve a precise determination of the first interaction point of the two 511 keV photons. The price to pay is an efficiency reduction for each stack of about 50%. The reduced dimensions of the scanner also improve the solid angle coverage resulting in a high sensitivity. Preliminary results were obtained with the MEGA prototype tracker. Here, we report on the results obtained with double sided silicon prototype detectors, manufactured by ITC-FBK, having an active area of 3 cm X 3 cm and a strip pitch of 500 μm. Two different strip widths of 300 μm and 200 μm, and two thicknesses of 1 mm and 1.5 mm, equipped with 64 orthogonal p and n strips on opposite sides were read out with the VATAGP2.5 ASIC, a 128channel "general purpose" charge sensitive amplifier. We describe the experimental setup, the measurements and the results in terms of spatial resolution, spectral and timing performances obtained with the prototype detectors.