arXiv subjects

Huan Niu

Publications and source records attributed to Huan Niu.

10 recordsLinked to original sources

arXiv2026

Using Fast Reading Current Integrator for Advanced Ion Beam Diagnostics Across Continuous and Pulsed Modes

A fast-reading current integrator is developed for high time-resolution and low-noise ion beam diagnostics under both continuous-wave and pulsed operating conditions. The system combines a low-leakage transimpedance front-end with a hybrid digitization architecture based on charge-balancing and voltage-to-frequency conversion. The input current is converted into a pulse stream corresponding to discrete charge quanta, enabling event-driven measurement with temporal resolution down to 0.5 ms while preserving a wide dynamic range and high linearity. The system further enables real-time pulse selection for instantaneous dose-rate estimation and reconstruction of time-dependent beam structures. A deterministic beam-interrupt signal is generated within <1 us upon reaching a predefined charge threshold, enabling fast feedback control. Additional functionalities, including threshold- and slope-based gating as well as phase-sensitive detection, enhance performance under noisy or modulated beam conditions. Calibration with precision current sources and beamline detectors demonstrates stable operation with excellent linearity and timing fidelity. The proposed system provides a compact and flexible platform for next-generation ion beam diagnostics requiring fast response, large dynamic range, and time-resolved measurement.

physics.ins-det↗

arXiv2025

Surface Hydrogen Coverage on Pt/Graphene Measured by Carbon Ion ERDA

Graphene, a two-dimensional monolayer of sp2-bonded carbon atoms in a honeycomb lattice, possesses exceptional electronic, mechanical, and quantum properties, making it highly attractive for energy storage, spintronics, and microelectronics. Functionalizing graphene with platinum (Pt) adatoms can further enhance its properties, particularly for hydrogen storage applications. In this study, we experimentally investigate hydrogen adsorption on Pt-decorated graphene using Elastic Recoil Detection Analysis (ERDA). By irradiating the Pt/graphene film with a 4.1 MeV C2+ ion beam and detecting recoiled hydrogen atoms at a 30 degree scattering angle, we obtain the hydrogen depth profile, providing critical insights into its storage behavior.

cond-mat.mtrl-sci↗

arXiv2023

Proton FLASH irradiation platform for small animal setup at Chang Gung Memorial Hospital

Background : Proton flash therapy is an emergency research topic in radiation therapy since the Varian announced the promising results from the first in human clinical trial of Flash therapy recently. However, it still needs a lot of researches on this topic, not only to understand the mechanism of the radiobiological effects but also to develop an appropriate dose monitoring system. Purpose : In this study we setup an experimental station for small animal proton Flash irradiation in a clinical machine. The dose monitoring system is able to provide real-time irradiation dose and irradiation time structure. Methods : The dose monitoring system includes homebrewed transmission ionization chamber (TIC), plastic scintillator based beam position monitor, and Poor Man Faraday Cup (FC). Both TIC and FC are equipped with a homebrewed fast reading current integral electronics device. The imaging guidance system comprises a moveable CT, laser, as well as attaching a bead on the body surface of the mouse can accurately guide the testing small animal in position. Results : The dose monitoring system can provide the time structure of delivered dose rate within 1 ms time resolution. Experimental testing results show that the highest dose in one pulse of 230 MeV proton that can be delivered to the target is about 20 Gy during 199 ms pulse period at 100 Gy/s dose rate. Conclusion : A proton research irradiation platform dedicated for studying small animal Flash biological effects has been established at Chang Gung Memorial Hospital. The final setup data represent a reference for the beam users to plan the experiments as well as for the improvement of the facility.

physics.med-ph↗

arXiv2019

High Resolution and High Precision Beam Profile Monitor for Particle Accelerator using linear contact image sensor

A compact beam-profile monitor was constructed using a linear contact image sensor attached to a plastic scintillator and tested using a 230 MeV proton beam. The results indicate that the beam distribution can be obtained in real-time, and the beam position with a precision of up to 0.03 mm. The compactness and high precision of the device hold considerable potential for it to be used as a beam-profile monitor and offline, daily quality assurance monitor in hadron therapy.

physics.med-ph↗

arXiv2019

Process Verification of Magnetic Ion Embedded Nanodiamonds Using Secondary Ion Mass Spectroscopy

Ion implantation is used to create magnetic ion embedded nanodiamonds for use in a wide range of biological and medical applications; however, the effectiveness of this process depends heavily on separating magnetic nanodiamonds from non-magnetic ones. In this study, we use secondary ion mass spectrometry to assess the distribution of magnetic ions and verify the success of separation. When applied to a series of iron/manganese embedded nanodiamonds, the sorting tool used in this study proved highly effective in selecting magnetic nanodiamonds. This paper also discusses the major challenges involved in the further development of this technology.

physics.app-ph↗

arXiv2019

Ordinary Low Alpha Proportional Counter with Low Cost Commercial Data Acquisition System

In this study, we present a low cost and commercially available data acquisition system (DAQ) for an ordinary low alpha proportional counter. By employing this DAQ system and aid of a simple physical model, we can easily rule out the common disadvantage of proportional type low alpha counters, such as sensitive to electromagnetic interference and vibration. The obtained results demonstrated that this method has improved the capability of an ordinary low alpha counter and even makes it easier to operate in a worse ground-loop laboratory.

physics.ins-det↗

arXiv2019

Iron Embedded Magnetic Nanodiamonds for in vivo MRI Contrast Enhancement

Although nanodiamonds have long being considered as a potential tool for biomedical research, the practical in vivo application of nanodiamonds remains relatively unexplored. In this paper, we present the first application of in vivo MRI contrast enhancement using only iron embedded magnetic nanodiamonds. MR image enhancement was clearly demonstrated in the rendering of T2-weighted images of mice obtained using an unmodified commercial MRI scanner. The excellent contrast obtained using these nanodiamonds opens the door to the non-invasive in vivo tracking of NDs and image enhancement. In the future, one can apply these magnetic nanodiamonds together with surface modifications to facilitate drug delivery, targeted therapy, localized thermal treatment, and diagnostic imaging.

physics.med-ph↗

arXiv2018

A New Boron-10 Delivery Agent for Boron Neutron Capture Therapy: Fluorescent Boron-10 Embedded Nanodiamonds

Boron neutron capture therapy is a powerful anti-cancer treatment, the success of which depends heavily on the boron delivery agent. Enabling the real-time tracing of delivery agents as they move through the body is crucial to the further development of boron neutron therapy. In this study, we fabricate highly bio-compatible boron-10 embedded nanodiamonds using physical ion implantation in conjunction with a two-step annealing process. The red fluorescence of the nanodiamonds allows their use in fluorescence microscopy and in vivo imaging systems, thereby making it possible to conduct tracking in real time. The proposed fluorescent boron-10 embedded nanodiamonds, combining optical visibility and boron-10 transport capability, are a promising boron delivery agent suitable for a wide range of biomedical applications.

physics.bio-ph↗

arXiv2017

Fe Doped Magnetic Nanodiamonds Made by Ion Implantation as Contrast Agent for MRI

We report in this paper a new MRI contrast agent based on magnetic nanodiamonds fabricated by Fe ion implantation. The Fe atoms that are implanted into the nanodiamonds are not in direct contact with the outside world, enabling this new contrast agent to be free from cell toxicity. The image enhancement was shown clearly through T2 weighted images. The concentration dependence of the T2 relaxation time gives a relaxivity value that is about seven times that of the regular non-magnetic nanodiamonds. Cell viability study has also been performed. It was shown that they were nearly free from cytotoxicity independent of the particle concentration used. The imaging capability demonstrated here adds a new dimension to the medical application of nanodiamonds. In the future one will be able to combine this capability of magnetic nanodiamonds with other functions through surface modifications to perform drug delivery, targeted therapy, localized thermal treatment and diagnostic imaging at the same time.

physics.bio-ph↗

arXiv2014

Interlayer Water Regulates the Bio-nano Interface of a \b{eta}-sheet Protein stacking on Graphene

Using molecular dynamics simulations, we investigated an integrated bio-nano interface consisting of a \b{eta}-sheet protein stacked onto graphene. We found that the stacking assembly of the model protein on graphene could be controlled by water molecules. The interlayer water filled within interstices of the bio-nano interface could suppress the molecular vibration of surface groups on protein, and could impair the CH...π interaction driving the attraction of the protein and graphene. The intermolecular coupling of interlayer water would be relaxed by the relative motion of protein upon graphene due to the interaction between water and protein surface. This effect reduced the hindrance of the interlayer water against the assembly of protein on graphene, resulting an appropriate adsorption status of protein on graphene with a deep free energy trap. Thereby, the confinement and the relative sliding between protein and graphene, the coupling of protein and water, and the interaction between graphene and water all have involved in the modulation of behaviors of water molecules within the bio-nano interface, governing the hindrance of interlayer water against the protein assembly on hydrophobic graphene. These results provide a deep insight into the fundamental mechanism of protein adsorption onto graphene surface in water.

physics.bio-ph↗