Verification of three dimensional charge transport simulations using ion microbeams

Optically targeted, ion microbeams provide a useful means of exposing individual structures within an integrated circuit to ionizing radiation. With this tool, calibrated, low damage, charge collection spectra can be measured from specific circuit structures without preceding ion damage to the structure or surrounding circuitry. This paper presents comparisons of calibrated, low damage, ion microbeam- based charge collection measurements and three-dimensional, charge transport simulations of charge collection for isolated n- and p- channel field effect transistors under conducting and non-conducting bias conditions

Crystal collimation experiment on 70-GeV proton accelerator

The first proof-of-principle experiment on "crystal collimation" was performed with 70-GeV protons on IHEP accelerator. A bent crystal installed in the ring as a primary element upstream of a collimator has reduced the radiation levels downstream in the accelerator by a factor of two. The measurements agree with Monte Carlo predictions

Assessing the Gender Impacts and Contributions of CCAFS Climate-Smart Villages in Lao PDR

From July – September 2021, a Gender Impact Assessment (GIA) was conducted to measure the impacts of the CSV gender strategy in regards to project participation, agricultural productivity, and overall socio-economic impacts at the village-cluster level. The GIA also aimed to provide insight on the impacts of the global COVID-19 pandemic on project objectives, and more specifically, women’s coping strategies as they relate to Climate-Smart Villages. Primary data was collected from two villages in Savannakhet Province, Lao PDR, and included a total of 28 respondents (9 female, 19 male). Although all respondents reported positive impacts to their livelihoods and improved resilience to climate change-related challenges, the CSV did not achieve gender-transformative outcomes. This is likely the result of a gender strategy which emphasized equal participation without improving knowledge on gender equality principles or fostering an enabling environment for social behaviour change. Also, since the CSV gender strategy did not include specific gender development targets, it could not be determined whether gender-specific outcomes were reached. This highlights the need for long-term systemic gender strategizing across sectors, programmes, and partnerships

The effect of layer number and substrate on the stability of graphene under MeV proton beam irradiation

The use of graphene electronics in space will depend on the radiation hardness of graphene. The damage threshold of graphene samples, subjected to 2 MeV proton irradiation, was found to increase with layer number and also when the graphene layer was supported by a substrate. The thermal properties of graphene as a function of the number of layers or as influenced by the substrate argue against a thermal model for the production of damage by the ion beam. We propose a model of intense electronically-stimulated surface desorption of the atoms as the most likely process for this damage mechanism.Comment: 20 pages, 5 figure

A large-area bent crystal shield for deflection of high-energy ions

10.1063/1.2824457Applied Physics Letters9126-APPL

A study of oscillations in the angular distribution of volume reflected ions from bent crystals

10.1016/j.nimb.2006.09.011Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms2522205-211NIMB

Near 100% deflection efficiency in bent crystals using multiple volume reflection

10.1016/j.nimb.2007.10.002Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms2652485-489NIMB

Porous silicon Bragg reflectors with sub-micrometer lateral dimensions

10.1364/OE.15.005537Optics Express1595537-554

Fabrication of suspended multilevel three-dimensional silicon micro- and nano-structures

Technical Proceedings of the 2013 NSTI Nanotechnology Conference and Expo, NSTI-Nanotech 20132158-16

The influence of ion induced damage on lateral charge collection and IBIC image contrast

High resolution, calibrated ion beam induced charge (IBIC) measurements from integrated circuit test structures have demonstrated that the measured charge collection in a device can exhibit significant change after only a few hundred ions/{micro}m{sup 2} exposure, which may easily be exceeded in the initial targeting of a structure. For the purposes of determining a circuit`s upset immunity or undamaged charge collection characteristics, such behavior must be accounted for in evaluating IBIC measurements. This paper examines the influence of low level, ion induced damage on the magnitude of the measured lateral charge collection and also its resulting impact on IBIC image contrast. The lateral charge collection process is first modeled by calculating the amount of charge which diffuses to a collecting junction as a function of carrier diffusion length and the distance between the ion strike and junction edge. The effect of accumulated ion induced damage on lateral charge collection is then incorporated in the model as a decrease in the resultant diffusion length. Calibrated IBIC measurements from the drain of a test FET structure are then explained using this predicted behavior