Detection Of Minimum Ionizing Particles Research Articles

Direct MIP detection with sub-10 ps timing resolution Geiger-Mode APDs

In this work we present and discuss the use of state-of-the-art Geiger-mode APDs, also known as single-photon avalanche diodes (SPADs), for the detection of minimum ionizing particles (MIPs) with best-in-class timing resolution. The SPADs were implemented in standard CMOS technology and integrated with on-chip quenching and recharge circuitry. Two devices in coincidence allowed to measure the time-of-flight of 180 GeV/c momentum pions with a coincidence time resolution of 22 ps FWHM (9.4 ps Gaussian sigma). This result paves the path for new generation of cheap plug-and-play trackers with extremely high spatial and timing resolution, meant to be used in beam test facilities.

Dark matter event in nuclear emulsions: Comparative analysis by time-resolved photoconductivity of silver halide grains

Dark matter (DM) detection by new nuclear emulsions composed of 40 nm AgBrI grains (Lindhard–Scharff theory) has been compared with minimum ionizing particle (MIP) detection and radiation therapy (RT) by conventional nuclear emulsions composed of 200 nm AgBrI grains (Bethe-Bloch theory), and with picture-taking by color films composed of 500–1000 nm AgBrI grains (band-to-band transition), and characterized by its uniqueness: latent image formation in the presence of electron–hole pairs with extremely high concentration (∼1000/grain) and insufficient space for chemical sensitization centers on a grain (∼10/grain). While AgBrI grains in nuclear emulsions for RT are also associated with electron–hole pairs with high concentration, they have space available for chemical sensitizations. Then, we have studied the effect of these characteristics on latent image formation by analyzing the behaviors of electrons and positive holes with variation of their concentrations in 200 nm AgBr grains by means of time-resolved microwave and radio-frequency photoconductivity methods. It has been predicted from the results of the above-stated experiments that DM detection and RT by nuclear emulsions are disturbed by direct recombination and by reaction between Agn and Br2 owing to high activity of positive holes on the contrary to MIP detection by nuclear emulsions and picture-taking by color films, both of which are solely disturbed by indirect recombination. On the basis of the obtained results, discussions are made on ideas to enhance the latent image formation in the presence of electron–hole pairs with high concentration.

Status and perspectives of hydrogenated amorphous silicon detectors for MIP detection and beam flux measurements

Hydrogenated amorphous silicon (a-Si:H) particle detectors have been considered as alternatives to crystalline silicon detectors (c-Si) in high radiation environments, due to their excellent radiation hardness. However, although their capability for particle flux measurement in beam monitoring applications is quite satisfactory, their minimum ionizing particle (MIP) detection has always been problematic because of the poor signal-to-noise ratio caused by a low charge collection efficiency and relatively high (compared to crystalline silicon) leakage current. In this article, after a review of the status of technological research for a-Si:H detectors, a perspective view on MIP detection and beam flux measurements with these detectors will be given.

Fabrication of a Hydrogenated Amorphous Silicon Detector in 3-D Geometry and Preliminary Test on Planar Prototypes

Hydrogenated amorphous silicon (a-Si:H) can be produced by plasma-enhanced chemical vapor deposition (PECVD) of SiH4 (silane) mixed with hydrogen. The resulting material shows outstanding radiation hardness properties and can be deposited on a wide variety of substrates. Devices employing a-Si:H technologies have been used to detect many different kinds of radiation, namely, minimum ionizing particles (MIPs), X-rays, neutrons, and ions, as well as low-energy protons and alphas. However, the detection of MIPs using planar a-Si:H diodes has proven difficult due to their unsatisfactory S/N ratio arising from a combination of high leakage current, high capacitance, and limited charge collection efficiency (50% at best for a 30 µm planar diode). To overcome these limitations, the 3D-SiAm collaboration proposes employing a 3D detector geometry. The use of vertical electrodes allows for a small collection distance to be maintained while preserving a large detector thickness for charge generation. The depletion voltage in this configuration can be kept below 400 V with a consequent reduction in the leakage current. In this paper, following a detailed description of the fabrication process, the results of the tests performed on the planar p-i-n structures made with ion implantation of the dopants and with carrier selective contacts are illustrated.

Studies of detector cells for a hadronic calorimeter based on plastic scintillators

In this paper, we study variations of a plastic scintillator tile coupled to silicon photomultiplier via a dome-shaped cavity originally developed in the CALICE collaboration. Four kinds of plastic scintillator detector cells with different sizes based on the structure were studied for applications in analog readout highly granular hadronic calorimeter (AHCAL) in future circular electron positron collider (CEPC) project. The responses to cosmic rays of the detector cells could reach 33.89 p.e./MIPs (minimum ionizing particles). The good results of both response uniformity and MIP detection efficiency (above 95%) show that the detector cells with larger sizes ( $$40\times 40\times 3$$ and $$50\times 50\times 3\,\hbox {mm}^{3}$$ ) could provide an option for AHCAL detector cells of CEPC detectors.

Modeling Charge Loss in CMOS MAPS Exposed to Non-Ionizing Radiation

A model, approximating minority carrier diffusion with a discrete random walk and accounting for radiation induced reduction of minority carrier lifetime, is proposed to predict the effects of neutron irradiation on the charge collection properties of monolithic active pixel sensors (MAPS) in CMOS technology. The model has been implemented in a Monte Carlo code to simulate MAPS operation in minimum ionizing particle detection systems. For the purpose of validating it, the results from the characterization of monolithic sensors irradiated up to an integrated fluence of 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">14</sup> 1- MeV-neutron equivalent/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> have been compared with the outcomes of the Monte Carlo simulations. The monolithic sensors taken into consideration for the model validation are based on two different CMOS processes, one featuring a triple well option, the other one featuring a quadruple well structure and a standard (10 Ω·cm) or high (1 kΩ·cm) resistivity epitaxial layer. Simulation results are shown to be in good agreement with experimental data. The consistency between the model and the measurement results seems to confirm that radiation induced increase in the recombination rate is the main source of charge collection degradation in neutron-irradiated MAPS.

Preliminary evaluation of Gaussian-doped monolithic active pixel sensors for minimum ionizing particles detection

The monolithic active pixel sensors (MAPS) using a standard dual-well CMOS process on lightly doped epitaxial wafers have demonstrated competitive tracking and imaging performance for minimum ionizing particles (MIP) detection. In this paper, a Gaussian-doped substrate is proposed to improve the performance of charge collection. Preliminary theoretical analysis and physical level simulations are presented. The results illustrate that the internal distributions of electric potential and electric field are improved and about 70% more charged-particle generated electrons can be collected in 50 ns (about one half with respect to the case of standard epitaxial layer) because the diffusion towards neighbor pixels is significantly reduced. Furthermore the manufacturability of such wafer is discussed.

Silicon Carbide for High Signal to Noise Ratio MIPs Detection From Room Temperature to 80$^{\circ}$C

The relatively low value of the number of electron-hole (e-h) pairs per micron for Minimum Ionizing Particles (MIPs) in SiC against the value for Si, imposes severe constrains on the crystallographic quality, the thickness and the doping concentration of the SiC epitaxial layer used as detection medium. In this work, a 85 mu m thick 4H-SiC epitaxial layer with a low doping concentration, N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">eff</sub> les 1 times 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">14</sup> cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-3</sup> , was used in order to have a high number ( ap 4700) of e-h pairs generated by a MIP in the active region. We present experimental data on the charge spectrum for beta MIPs from a <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">90</sup> Sr source, collected in a temperature range from room temperature up to 81degC.

Low-Power Amplifier-Discriminators for High Time Resolution Detection

Low-power amplifier-discriminators based on a so-called NINO architecture have been developed with high time resolution for the readout of radiation detectors. Two different circuits were integrated in the NINO13 chip, processed in IBM 130 nm CMOS technology. The LCO version (Low Capacitance and consumption Optimization) was designed for potential use as front-end electronics in the Gigatracker of the NA62 experiment at CERN. It was developed as pixel readout for solid-state pixel detectors to permit minimum ionizing particle detection with less than 180 ps rms resolution per pixel on the output pulse, for power consumption below 300 muW per pixel. The HCO version (High Capacitance Optimization) was designed with 4 mW power consumption per channel to provide timing resolution below 20 ps rms on the output pulse, for charges above 10 fC. Results presented show the potential of the LCO and HCO circuits for the precise timing readout of solid-state detectors, vacuum tubes or gas detectors, for applications in high energy physics, bio-technologies or medical imaging.

Fast scintillation counters for the DO Muon System Upgrade

The design and main parameters of the completely redesigned DO Forward Angle Muon System (FAMUS: 1.0<|/spl eta/|<2.0) for the next high luminosity Tevatron Collider run are reported. Results of the studies of trigger scintillation counters based on fast scintillator Bicron 404 A and WLS bars SOFZ-105 are presented. We report about results of test beam studies of prototype counters including minimum ionizing particle detection efficiency, time resolution and amplitude response. Radiation ageing of scintillating materials for doses up to 1 Mrad, phototube magnetic shielding in field of up to 700 G and ageing of phototubes are presented. All tests show the robustness of scintillation counters as triggering detectors for the new muon system for a long period.

Forward muon system for the DØ detector upgrade

The design and main parameters of the completly redesigned DØ Forward Angle MUon System (FAMUS: 1.0<|η|<2.0) for the next high luminosity Tevatron Collider run are reported. Results of the studies of trigger scintillation counters based on fast scintillator Bicron 404A and WLS bars SOFZ-105 are presented. We report about results of test beam studies of prototype counters including minimum ionizing particles detection efficiency, time resolution and amplitude response. Radiation ageing of scintillating materials for the doses up to 1Mrad, phototubes magnetic shielding in the fields of up to 700G and ageing of phototubes are presented. Mini-Drift Tubes (MDTs) are chosen as FAMUS tracking detectors. The detector is a drift wire chamber with a metallic cathode. The detector operates in proportional mode with a fast freon–methane gas mixture to provide high drift velocity, adequate counting rate and low ageing. A description of the performance of the MDT is given. Studies of two prototypes in test beams were performed at FNAL and JINR. Obtained coordinate accuracy is around 0.5mm r.m.s. All tests show robustness of MDT as tracking detector of the new muon system for a long period in high DØ background radiation conditions.

Detection of minimum-ionizing particles and nuclear counter effect with pure BGO and BSO crystals with photodiode readout

Long BGO (Bi 4Ge 3O 12) and BSO (Bi 4Si 3O 12) crystals coupled with silicon photodiodes have been used to detect minimum-ionizing particles (MIP). With a low-noise amplifier customized for this purpose, the crystals can detect MIPs with an excellent signal-to-noise ratio. The nuclear counter effect is also clearly observed and measured. Effect of full and partial wrapping of a reflector around the crystal on light collection is also studied.

Thick (∼ 50 μm) amorphous silicon p-i-n diodes for direct detection of minimum ionizing particles

Thick (∼ 50 μm) amorphous silicon (a-Si:H) p-i-n diodes of device quality are made by helium dilution of the process gas and heat treatment for application to minimum ionizing particle detection. Dilution of SiH 4 with He decreased the dangling bond density and increased the deposition rate. The internal stress, which causes substrate bending and delamination, was reduced by a factor of 4 to ∼ 90 MPa when deposited at low (150°C) temperature. The electronic quality of the a-Si:H film was somewhat degraded when grown at a low temperature, but could be mostly recovered by subsequent annealing at 160°C. By this technique 50 μm thick n-i-p diodes were made without significant substrate bending, and the electronic properties, such as electron mobility and ionized dangling bond density, were suitable for detecting minimum ionizing particles. Diode readouts and integrated amplifiers for pixel arrays are also described.

X-rays operation of a thin film NbVN superconducting-strip particle detector

Using a current biased 2 μm wide, thin film (Nb 0.8V 0.2)N superconducting strip operated at 1.4 K, we were able to detect voltage pulses due to the superconducting to normal transition induced by a 55Fe 6 keV X-rays source. At high bias currents the estimated counting efficiency was close to 60%. The detector performance and its potential application for X-rays and minimum ionizing particles detection are discussed in the framework of the recent literature on the subject.

Exploration of GaAs structures with π-ν junction for coordinate sensitive detectors

The results of a systematic study of GaAs samples as the basis for the construction of radiation resistant coordinate sensitive detectors are presented. The technology to manufacture high resistivity GaAs layers has been optimized. As a result we have produced samples with charge collection efficiency greater than 95% and with a time response of less than a few ns for minimum ionizing particle detection. The study of the radiation resistance of the GaAs samples has shown that their main characteristics degrade by less than by 20% at a neutron fluence of the order of 10 15 cm −2 and do not worsen at a absorbed γ-dose of 11 Mrad.

Preparation of submicron (NbV)N superconducting thin film strip particle detectors

Superconducting thin film particle detectors can be specially attractive for minimum ionizing particle detection due to the high efficiency and low sensitivity to radiation damage. In this paper we describe the fabrication procedure and the characterization of (NbV)N films and the set-up of photolithography processes to realize well defined submicron lines on these films in order to produce and test, in the near future, full operating detectors based on such material.

Detection of minimum-ionizing particles in hydrogenated amorphous silicon

Based on previously-reported results of the successful detection of alpha particles and 1 and 2 MeV protons with hydrogenated amorphous silicon (a-Si:H) diodes, detection of a single minimum-ionizing particle will require a total sensitive thickness of approximately 100–150 μm, either in the form of a single thick diode, or as a stack of several thinner diodes. Signal saturation at high dE dx makes it necessary to simulate minimum ionization in order to evaluate present detectors. Two techniques, using pulsed infrared light, and pulsed X-rays, give single-pulse signals large enough for direct measurements. A third, using beta rays, requires multiple-transit signal averaging to produce signals measurable above noise. Signal amplitudes from the a-Si: H limit at 60% of the signal size from Si crystals extrapolated to the same thickness. This is consistent with an a-Si: H radiation ionization energy, W = 6 eV/electron-hole pair. Beta-ray signals are observed at the expected amplitude.

Development of a Multistep Parallel-Plate Chamber as Time Projection Chamber End-Cap or Vertex Detector

We have tested a prototype two-step parallel-plate avalanche chamber capable of large stable gains (in excess of 105) and having very good intrinsic localization and timing properties. The only active electrode consists of a printed-circuit board with densely packed readout strips alternated with small pad rows. Recording pulse-height distributions on several adjacent strips and pads, we have determined the gain characteristics of the device and its localization accuracy in the detection of soft X-rays. The results are promising, and with this device we intend to study the timing and localization properties in the detection of minimum-ionizing particles, in a geometry similar to the one of the TPC.

A thin detector with ionization tubes for high energy electrons and photons

The possibility of measuring the energy of electrons and photons with a simple detector consisting of a lead convertor and ionization tubes filled with pure argon has been studied. The measurements have been performed in a 26.6 GeV electron beam. The best energy resolution σ/E ∼ 16% was achieved for a convector thickness of 40 mm and an argon pressure ⪆20 atm.The performance of the detector in magnetic fields up to 16 kG has also been studied. It turned out that the mean pulse height rises approximately linearly with increasing magnetic field and becomes flat at H ∼ 10 kG. This behavior is the same for magnetic fields perpendicular and parallel with respect to the ionization tubes. The energy resolution depends weakly on the magnetic field.Ionization tubes filled with argon or xenon under high pressure may be used for minimum ionizing particle detection.

Minimum Ionizing Particle Detection by Secondary Electron Emission

The use of secondary electron emission to detect high energy particles is investigated. Low density KCl layers have been tested to detect MeV electrons, 400-750 MeV protons and high energy deuterons. The efficiency and the secondary electron spectrum are presented. The results justify the use of low-density KCl layer to detect minimum ionizing particles.