Time Of Flight Measurements Research Articles

Accurate measurement of optical fiber time delay based on frequency domain reflectometry

Optical fiber time delay system has been widely used in optical-controlled phased array antenna, radar distributed network, interferometric optical fiber hydrophone and high-speed photoelectric chip. These applications require high-accuracy and high-stability time delay generated by the system. Time delay measurement directly determines the precision and resolution of the system. Therefore, high-precision time delay measurement method is of great significance in developing the optical fiber delay system. In this paper, progress and problems of optical fiber time delay measurements are discussed. A new method of precisely measuring the time delay in optical fiber is proposed. We use the frequency domain reflectometry (FDR) to avoid the discrepancy between measuring range and measuring precision, which exists in both time-of-flight (TOF) method and phase discrimination approach. An intensity modulated 1064 nm laser signal is used as a light source. The modulation frequency is tuned from 10 MHz to 200 MHz in steps of 0.5 MHz. The spectrum of echo signal is obtained by measuring the amplitudes and phases of echo signals at different frequency points. The delay information is obtained via the inverse fast Fourier transform (IFFT). The precision of delay measurement in our method is determined by step size of frequency variation, and a higher-precision measurement is realized by using interpolation zero algorithm. Since our method is not to modulate the optical frequency, but to control the frequency of the modulation signal loaded on the electro-optic modulator, it is easy to achieve the high-precision and high-linearity frequency modulation. In this paper, theoretical analysis and time delay measurement are used to compare the FDR method with conventional TOF measurement method. The accurate measurement of 33–200 ps is realized, and measurement error is lower than 7 ps. We also design an incremental measurement experiment to study the resolution of the FDR method, which achieves a delay resolution of 3.3 ps. The influence of temperature jitter is analyzed to prove the reliability of experimental results. It proves that the FDR method has a higher measuring accuracy than the TOF method. The time delay measurement precision can be further improved by expanding the modulation bandwidth. Our method is to be applied to an optical fiber delay system to improve the precision and resolution of system delay.

Characterization and Architecture of Monolithic N⁺P-CMOS-SiPM Array for ToF Measurements

This article focuses on the characterization and architecture of a new mixed design approach to monolithic CMOS-silicon-photomultiplier (SiPM), where the mixed-signal circuitry as well as the logical concepts are implemented at the die level. The new architecture contains two key areas: 1) a method for sampling, filtering, and converting the electrical signal generated by the SiPM to the digital domain by taking advantage of the nature of the SiPM as an “optical-to-digital converter” and 2) a fully digital configurable method, which requires just one clock generator, enabling sampling at an adjustable time window (gating method) and reduces background noise. We report the design, simulation, and measurement results. The system was fabricated at a low-cost $0.18~\mathrm {[{\mu {\mathrm{ m}}}]}0.18$ - $\mu \text{m}$ CMOS process yet achieves a clock rate of 1 GHz, high timing and photon counting resolution, and low jitter. The reported demonstrator may be applied to 3-D range measurements, light detection and ranging (LIDAR), time-of-flight (ToF) system, and gaming systems.

Measurement of TOF of fast neutrons with 238U target

We developed a Dual-PPACs detector for fast neutron measurements that consists of two sets of PPAC: conventional PPAC and fission PPAC. A238U(U3O8) coating is placed in the fission PPAC’s anode, which is used as the neutrons conversion layer. An experiment was performed to measure neutron time-of-flight (TOF) in which 252Cf spontaneous fission source was used. An excellent time resolution of 164ps has been observed at 6 mbar in isobutene gas. With the excellent time resolution of Dual-PPACs detector, exact neutron energy can be extracted from the timing measurement. The experimental detection efficiency was 1.9 × 10−7, consistent with the efficiency of 2.5 × 10−7 given by a Geant4 simulation. Ultimately, the results show that the Dual-PPACs detector is a suitable candidate for measuring fast neutrons in the future CiADS system.

Optimization of Beam Arrival and Flight Time Measurement System Based on Cavity Monitors at the SXFEL

To fully optimize the operation of a high-gain free-electron laser (FEL) facility and to offer opportunities for time-resolved experiments, a highly accurate synchronization between an electron bunch and a seeded laser is required. Thus, a high-precision and high-resolution beam arrival and flight time measurement system is built at the Shanghai soft X-ray FEL (SXFEL) facility. For the SXFEL, a beam arrival time resolution better than 100 fs is required. A phase cavity-based detection scheme for this measurement has already been adopted at the SXFEL. To further optimize system performance, the impacts of clock jitter, trigger jitter, and signal analysis length on the measurement uncertainties are analyzed, and related subsystems are upgraded and optimized accordingly. The beam arrival time is successfully measured, and the initial measurement uncertainty is better than 45 fs. Furthermore, a dual-cavity mixing scheme is realized to measure the beam flight time or pseudo-beam arrival time, and the measurement resolution of the beam flight time using this technique is 13 fs.

Effects of High-Dose X-Ray Irradiation on the Hole Lifetime in Vacuum-Deposited Stabilized a-Se Photoconductive Films: Implications to the Quality Control of a-Se Used in X-Ray Detectors

Stabilized amorphous selenium (a-Se)-based digital flat-panel X-ray imaging detectors are widely used in modern mammography. The dependence of the hole lifetime, $\tau _{h}$ , in a-Se on high-dose X-ray irradiation under high electric fields is examined. The X-ray-induced effects on the samples were studied using conventional time-of-flight (TOF) and interrupted-field time-of-flight (IFTOF) techniques. The samples were placed under a high electric field (5–10 V/ $\mu \text{m}$ ) and exposed to X-ray irradiation, after which TOF and IFTOF measurements were taken to find the hole drift mobility and lifetime after X-ray exposure. There was no observed change in the hole drift mobility but there was a large drop in the hole lifetime. The reduction in the hole lifetime depended only on the total or accumulated dose and the applied field. There was no dependence on the dose rate, over a range of 0.12–2.5 Gy/s, or on the X-ray photon energy, over a range of 50–90 keVp (corresponding to a mean photon energy of 31.9–44.7 keV). The implications of these findings can be seen through the calculation of the charge collection efficiency (CCE). The results show that the effects of X-ray irradiation on a-Se X-ray detectors are considerable when the detector is under an applied field during exposure, but are minimized when the operating field is high (corresponding to a high CCE) and the a-Se is of high-quality electronic grade material.

Off-Axis Characterisation of the CERN T10 Beam for low Momentum Proton Measurements with a High Pressure Gas Time Projection Chamber

We present studies of proton fluxes in the T10 beamline at CERN. A prototype high pressure gas time projection chamber (TPC) was exposed to the beam of protons and other particles, using the 0.8 GeV/c momentum setting in T10, in order to make cross section measurements of low energy protons in argon. To explore the energy region comparable to hadrons produced by GeV-scale neutrino interactions at oscillation experiments, i.e., near 0.1 GeV of kinetic energy, methods of moderating the T10 beam were employed: the dual technique of moderating the beam with acrylic blocks and measuring scattered protons off the beam axis was used to decrease the kinetic energy of incident protons, as well as change the proton/minimum ionising particle (MIP) composition of the incident flux. Measurements of the beam properties were made using time of flight systems upstream and downstream of the TPC. The kinetic energy of protons reaching the TPC was successfully changed from ∼0.3 GeV without moderator blocks to less than 0.1 GeV with four moderator blocks (40 cm path length). The flux of both protons and MIPs off the beam axis was increased. The ratio of protons to MIPs vary as a function of the off-axis angle allowing for possible optimisation of the detector to select the type of required particles. Simulation informed by the time of flight measurements show that with four moderator blocks placed in the beamline, (5.6 ± 0.1) protons with energies below 0.1 GeV per spill traversed the active TPC region. Measurements of the beam composition and energy are presented.

An insight into the charge carriers transport properties and electric field distribution of CH3NH3PbBr3 thick single crystals

Thanks to their unique combination of semiconducting properties and a large cross section for energetic photons, metal halide perovskites could theoretically achieve high x-ray to charge carriers conversion rates, making them materials of high interest for the direct x-ray detection. In this work, we focus on the transport properties of methylammonium lead tribromide (MAPbBr3) single crystals. Time of Flight measurements and x-ray focused experiments along the edge of the samples were carried out. We report homogenous holes transit throughout the thickness of the samples as well as poor electrons transit. We also report the continuity of the electric field throughout the thickness of the MAPbBr3 samples, and we present preliminary fitting results to discuss its nature.

Pulsed light time-of-flight measurement based on a differential hysteresis timing discrimination method.

In the pulsed light time-of-flight (ToF) measurement, the timing point generated in the receiver channel is very important to the measurement accuracy. Therefore, a differential hysteresis timing discrimination method is proposed to generate timing points of the receiver channel. This method is based on utilizing the unbalanced characteristics of the fully differential operational amplifier circuit as well as introducing extra hysteresis levels to achieve the stable generation of timing points. With this method, fewer circuit components are consumed and the dynamic range of the receiver channel is not limited by its linear range. The experiments demonstrate that a receiver channel applying the proposed discrimination reaches better single shot accuracy compared to that using leading-edge timing discrimination. This method is also suitable for the timing walk error compensation by means of pulse width. Finally, these results verify the effectiveness of the proposed method in pulsed light ToF measurement.

Contrast modes in a 3D ion transmission approach at keV energies

We present options for visualizing contrast maps in 3D ion transmission experiments. Simultaneous measurement of angular distributions and flight time of ions transmitted through self-supporting, single-crystalline silicon foils allows for mapping of intensity and different energy loss moments. The transmitted projectiles were detected mainly for random beam-sample orientation using pulsed beams of He ions and protons with incident energies 50 and 200 keV. Differences in contrast, observed when varying the projectile type and energy, can be attributed to sample nuclear and electronic structure and bear witness to impact parameter dependent energy loss processes. Our results provide a base for interpretation of data obtained in prospective transmission studies when for example using a helium ion microscope.

Underwater Target Tracking in Uncertain Multipath Ocean Environments

In order to address the problem of 3-D localization of an underwater target using a 2-D active sonar with unknown oceanographic factors in a multipath environment with heavy clutter, a novel iterative framework based on Maximum Likelihood Probabilistic Data Association (ML-PDA), which considers ocean sound speed profile (SSP) uncertainty and utilizes multiple detections to realize 3-D position estimation with only bearing and time of flight (ToF) measurements, is proposed. ML-PDA is highly effective in low SNR target detection. However, it is limited by its assumption of at most one target-originated detection within a scan. To estimate the 3-D target state with multipath detections under weak observability conditions, we first extend the ML-PDA into a multipath ML-PDA by enumerating the combined association events formed from multiple detection patterns. In contrast to the situation in air target tracking, the water column is nonhomogeneous and the underwater sound speed profile varies, influenced by uncertain ocean factors, e.g., temperature, salinity, and pressure. The resultant acoustic signal travels in a curvilinear path instead of a straight line. In this article, an SSP-dependent ToF measurement model is derived for both the direct path and the surface-reflected path between two remote nodes, so that the SSP uncertainty can be addressed systematically. By adopting an iterative prediction-update methodology, we first propagate the SSP uncertainty into the modified measurement covariance with the help of the unscented sampling technique. Then, we formulate a new joint likelihood ratio (JLLR) function based on the modified measurement covariance within the multidetection ML-PDA framework. A hybrid optimization method with grid search and particle swarm optimization is applied to solve the complex JLLR objective function and to find the optimal target state estimate from a large surveillance region. Finally, a sequential update technique is used to update the SSP state with the estimated target state and sensor measurements. In subsequent iterations, a more accurate JLLR can be rebuilt based on the updated SSP state, which can help find a better parameter estimate eventually. In addition, the Cramér-Rao lower bound, which quantifies the best possible accuracy in the presence of SSP uncertainties, is derived and analyzed. Numerical simulations confirm the underwater target localization performance of the proposed method in the presence of heavy clutter in an unknown ocean environment with a realistic sound propagation model.

Electron-impact recombination and excitation rates for charge-state-selected highly charged Si ions

Charge-state selective recombination rate coefficients were measured by time of flight (TOF) analyzed highly charged Si ions extracted from an electron-beam ion trap. Additionally, the combination of simultaneous TOF and x-ray measurements and a separation of the dielectronic recombination contribution in the x-ray spectra is used for extracting electron-impact excitation rate coefficients for several overlaying charge states. Experimentally derived dielectronic recombination spectra for XIII and XIV Si are compared and found in excellent agreement with the results of relativistic many-body perturbation theory calculations.

Multi-strategy Measurement of High-resolution Ultrasonic TOF

Jiao, Y.; Li, Z.; Zhu, J., and Zhang, B., 2020. Multi-strategy measurement of high-resolution ultrasonic TOF. In: Zheng, C.W.; Wang, Q.; Zhan, C., and Yang, S.B. (eds.), Air-Sea Interaction and Coastal Environments of the Maritime and Polar Silk Roads. Journal of Coastal Research, Special Issue No. 99, pp. 389–395. Coconut Creek (Florida), ISSN 0749-0208.Ultrasonic transducers are widely used in liquid sound velocity measurement. Acquisition of time-of-flight (TOF) is the key technology of high precision measurement of sound velocity.In this paper, to measure TOF with high precision, a Multi-strategy Measurement technique is proposed, which is able to locate the region of interest of the signals received echo waveform, and the wavelet denoising is carried out. To evaluate the proposed method, in an identified environment, the experiments were performed under defined the distance between transmitter and receiver in pure water at 30°C. The experiments were performed that, in the sound velocity measurement, the method has a high adaptability, which can achieve the goal of removing noise and improving detection accuracy. Although this paper focus on sound velocity in pure water, the method described may also find application in air.

A Damage Localization Method With Multimodal Lamb Wave Based on Adaptive Polynomial Chirplet Transform

Ultrasonic Lamb wave testing allows health monitoring for plate structures and has been extensively applied in the modern industry. To obtain the location and further form the damage imaging, the time of flight (TOF) is a pivotal parameter. However, the dispersive and multimodal nature of the Lamb wave obstructs the accurate measurement of TOF. The objective of this article is to develop efficient techniques to separate multimodal Lamb wave signals and accomplish accurate damage localization. The narrowband Lamb wave is generated by the excitation signal with a center frequency of 150 kHz. The fundamental symmetric and antisymmetric modes are exploited. The adaptive polynomial chirplet transform (CT) is proposed to decompose the Lamb wave signals and identify the modes. Then, the instantaneous frequency characteristics are utilized to extract time information. Thus, the TOF is obtained and damage location can be calculated. The reconstruction error is defined to quantitate the difference between the reconstructed signal and the received signal. The obtained reconstruction errors from the simulation and experiment are 0.1631 and 0.2875, respectively. The varied defect location is adopted to obtain the TOF estimation. The results show that the proposed method outperforms the CT and cross correlation, especially for the longer propagation distances where the dispersion effect is distinct. For experiments considering the defect and boundary reflection, the localization errors of the collinear defect are 2.51% and 3.04% for the two Lamb wave modes. In comparison with smoothed-pseudo-Wigner–Ville distribution and CT, the proposed method owns superior performance on mode identification and location accuracy.

CMUT Time of Flight Gas Sensor By Phase Shift Measurement

Introduction The most common approach to measure a gas concentration consists in coating the exposed part of a sensor with a functionalized film in order to absorb the targeted gas [1].However, it is well known that a sensitive coating compromises the long term stability of the sensor mostly due to aging of such film [2]. This has resulted in an increasing interest in uncoated sensors, which rely on the change of the physical properties (mass density for instance) of their surrounding gas despite their lack of selectivity.One example of uncoated sensors are time of flight sensors. Capacitive micromachined ultrasonic transducers (CMUTs) [3], have been previously used for time of flight gas sensing due to their easy integration capabilities. However, these methods rely on peak detection algorithms which can be very complex and hard to integrate.In this study, we present a new simple approach using the phase shift of a continuous ultrasonic wave to measure the time of flight between two CMUT arrays. The principle of this method along with the experimental setup and results will be presented in the following sections. Sensor Figure 1 shows a picture of the sensor used in this study. It consists of an array of thousands of CMUTs as the one illustrated in Figure 2 fabricated according to [4]. By applying a bias Vdc and an alternative voltage Vdc between its electrodes, the top electrode vibrates generating an ultrasonic mechanical vibration in the gas (emitter mode). Similarly, when the membrane vibrates due to a mechanical vibration of the gas, the CMUT’s capacitance changes generating an electrical signal (receiver mode). Principle The experimental setup schematics are shown in Figure 3. One CMUT array working as emitter (1) generates a continuous ultrasonic wave at a given angular frequency (ω) through a network analyzer in gain/phase configuration (2). The wave propagates through the gas at a velocity (C) that depends on the gas composition. For this study the gas consists of N2 (similar to air) and either CO2 or H2. In the case of an ideal gas, its expression is given by Equation 1 where R = 8.314 J.K-1.mol-1, T = 20°C, x is the molar fraction of a gas (either N2 or the mixture), M is the corresponding molar mass and γ is the adiabatic index given by Equation 2 where cp and cv are, respectively, the isobar and isochoric heat capacitance per unit mass. After a delay τ, the wave reaches a second CMUT array (3) working in receiver mode. The generated signal is conditioned by a charge amplifier (4) and then injected back to the network analyzer. At a given time t, the phase difference φ between the emission and the reception is proportional to τ as shown in Equation 3. Therefore, the slope of the curve φ(ω ) changes when the gas composition changes. To verify this experimentally, the curves φ( w) are shown for pure N2 (black), 4% of H2 in N2 (blue) and 4% of CO2 in N2 (green) in Figure 4. Results 1-Sensitivity Tests under H2 and CO2 in N2 at different concentrations (4%, 3%, 2% and 1%) were performed and are shown respectively in Figure 5 and Figure 6. From these measurements, the calibration curves were obtained with good linearity (Figure 7). The sensitivities (slope of the curves) to each gas were measured and their values are, respectively, S{H2,exp}=-92ns/% and S{CO2,exp}=55ns/%. Their corresponding theoretical values around a given concentration (xmix=4%) can be approximated by Equation 4. The obtained values are respectively, S{H2,th}=-135ns/% and S{CO2,th}=97ns/% which are consistent with the experiments. 2-Limit of Detection Finally, knowing the sensitivity to a gas Sgas , a theoretical limit of detection (LOD) can be estimated with Equation 5 where σ=1ns, is the noise standard deviation of the sensor. The obtained values for H2 and CO2 are, respectively, LODH2 =0.03%, LODCO 2 =0.05%.In order to verify this experimentally, tests at low concentrations for H2 and CO2 were performed and are shown, respectively, in Figure 8 and Figure 9. The obtained results are consistent with the calculations. Conclusion In this study we presented a new way of determining the concentration of binary gas mixtures without a sensitive chemical coating through a time of flight measurement. We verified this method using N2 as a reference and both CO2 and H2 as analytes. Finally, we showed experimentally that the LOD in N2 is less than 0.03% for H2 and less than 0.05% for CO2 which, despite being worse than what has been reported with a coated sensor, remain comparable to the state of the art of uncoated sensors and to some commercial coated sensors.

Model Study of Transient Imaging With Multi-Frequency Time-of-Flight Sensors.

As an emerging imaging modality, transient imaging that records the transient information of light transport has significantly shaped our understanding of scenes. In spite of the great progress made in computer vision and optical imaging fields, commonly used multi-frequency time-of-flight (ToF) sensors are still afflicted with the band-limited modulation frequency and long acquisition process. To overcome such barriers, more effective image-formation schemes and reconstruction algorithms are highly desired. In this paper, we propose a compressive transient imaging model, without any priori knowledge, by constructing a near-tight-frame based representation of the ToF imaging principle. We prove that the compressibility of sensor measurements can be presented in the Fourier domain and held in the frame, and the ToF measurements possess multi-scale characteristics. Solving the inverse problems in transient imaging with our proposed model consists of two major steps, including a compressed-sensing-based approach for full measurement recovery, which essentially reduces the capture time, and a wavelet-based transient image reconstruction framework, which realizes adaptive transient image reconstruction and achieves highly accurate reconstruction results. The compressive transient imaging model is suitable for various existing multi-frequency ToF sensors and requires no hardware modifications. Experimental results using synthetic and real online datasets demonstrate its promising performance.

Effects of background gases and pressure in pulsed laser deposition of Al-doped ZnO

Background gases (O2, He or Ar) with the pressure from ~ 10−3 Pa to 133.3 Pa are used in 355 nm laser deposition of Al-doped ZnO at room temperature. The effects of these gases and pressure on plasma formation are studied by optical emission spectroscopy (OES) and time of flight (TOF) measurement. The OES results show that the emission intensity of the species in O2 and Ar decrease slightly and then increase exponentially above ~ 5 Pa. The emission intensity in Ar is the highest, followed by emission in O2 whilst the emission in He is low and weakly depend on background gas pressure. TOF measurements indicate that the ion velocity decrease with increasing O2 and Ar pressure at about 5–10 Pa. The ion velocity is highest in He while the ion velocities in O2 and Ar are similar. Thin-film samples deposited in different gas at 2.6 Pa are amorphous, but those deposited at 133.3 Pa are crystalline and exhibit different morphologies and optical properties depending on type of gas. Samples deposited in O2 are highly transparent but those deposited in He and Ar contain nano and micron-sized structures with <50% transmittance. In addition, Zn crystallites are detected by X-ray diffraction.

Double-bunch unfolding methods for the Back-n white neutron source at CSNS

The Back-n white neutron source at China Spallation Neutron Source (CSNS) is designed specifically for nuclear data measurements and multidisciplinary neutron applications. The time of flight (TOF) method is deployed to obtain a high resolution of neutron energy. In the normal operation mode of CSNS there are two proton bunches with a time interval of 410 ns in each pulse which has a repetition frequency of 25 Hz. Due to the superposition of the event distributions corresponding to two bunches, the resolution of the TOF measurement at Back-n will be degraded by the double-bunch characteristics if the measured event distribution is used directly without unfolding, especially in the higher neutron energy region. To nearly recover the event distribution corresponding to a single proton bunch, the unfolding methods have been developed to obtain better time resolution and energy resolution. Two kinds of unfolding algorithms based on the iterative Bayesian method and the iterative event re-distribution method, respectively, have been developed and tested with simulated data and experimental data. The developed methods have shown nice performance in unfolding the double-bunch event distributions with high accuracy and fast convergence. With the deploying of the unfolding methods, the data of the first batch experiments conducted at Back-n in the normal double-bunch mode were analyzed and nearly the same time resolution as in the case of the single-bunch mode has been obtained.

Measurement of 12C Fragmentation Cross Sections on C, O, and H in the Energy Range of Interest for Particle Therapy Applications

In a carbon ion treatment the nuclear fragmentation of both target and beam projectiles impacts on the dose released on the tumor and on the surrounding healthy tissues. Carbon ion fragmentation occurring inside the patient body has to be studied in order to take into account this contribution. These data are also important for the development of the range monitoring techniques with charged particles. The production of charged fragments generated by carbon ion beams of 115–353 MeV/u kinetic energy impinging on carbon, oxygen, and hydrogen targets has been measured at the CNAO particle therapy center (Pavia, Italy). The use of thin targets of graphite (C), PMMA (C2O5H8) and polyvinyl-toluene [plastic scintillator (PS), ${\text{C}}_{b}{\text{H}}_{a}$ ] allowed to measure fragments production cross sections, exploiting a time-of-flight (ToF) technique. PS detectors have been used to perform the ToF measurements, while LYSO crystals have been used for the deposited energy measurement and to perform particle identification. Cross sections have been measured at 90° and 60° with respect to the beam direction. The measured proton, deuteron, and triton differential production cross sections on C, O, and H, obtained exploiting the target subtraction strategy, are presented here as a function of the fragment kinetic energy.

An 8-Tap CMOS Lock-In Pixel Image Sensor for Short-Pulse Time-of-Flight Measurements.

An 8-tap CMOS lock-in pixel image sensor that has seven carrier-capturing and a draining time window was developed for short-pulse time-of-flight (TOF) measurements. The proposed pixel for the short-pulse TOF measurements has seven consecutive time-gating windows, each of which has the width of 6 ns, which is advantageous for high-resolution range imaging, particularly for relatively longer distances (>5 m) and under high ambient light operations. In order to enhance the depth resolution, a technique for the depth-adaptive time-gating-number assignment (DATA) for the short-pulse TOF measurement is proposed. A prototype of the 8-tap CMOS lock-in pixel image sensor is implemented with a 1POLY 4METAL 0.11-μm CIS process. The maximum non-linearity error of 1.56%FS for the range of 1–6.4 m and the depth resolution of 6.4 mm was obtained at 6.2 m using the DATA technique.

Low-penetrance susceptibility variants and postmenopausal oestrogen receptor positive breast cancer

The risk of breast cancer (BC) in women is high and many factors including genetic factors increase the risk for the disease. It is revealed that the variations of low-penetrance susceptibility genes are important for carcinogenesis as they interact with the environmental and hereditary factors. Recently, the list of BC-associated common single nucleotide polymorphisms (SNPs) and chromosomal loci in low-penetrance susceptibility genes have been expanded in genomewide association studies. FGFR2, LSP1, MAP3K1, TGFB1, TOX3, 2q35 and 8q loci variations are some examples for these common SNPs. These SNPs and their association with BC risk was investigated in many different populations. Therefore in this study, we aimed to evaluate low-penetrance susceptibility SNPs; namely FGFR2 rs1219648, rs2981579, rs2981582; MAP3K1 rs889312; TOX3 rs3803662; LSP1 rs909116, rs3817198 and SLC4A7 rs4973768 together, for the firsttime in Turkish postmenopausal oestrogen receptor positive BC cases. Following the DNA isolation, multiplex PCR and matrix-assisted laser desorption/ionization mass spectrometry with time of flight measurement (MALDI-TOF) based SNP analysis were performed. MAP3K1 rs889312 SNP demonstrated the strongest association with BC risk among the other low penetrant SNPs, it was also associated with BC risk in a dominant model. Only in a ressesive model, TOX3 rs3803662 was associated with BC risk. In addition, rs4973768 CC and rs909116 CC genotypes are correlated with higher tumour size which is not reported in the literature as yet; on the other hand there are no associations between any of the other SNP genotypes and clinopathological parameters. In our opinion, MAP3K1 rs889312 may be a good BC susceptibility biomarker candidate for Turkish population.