J. F. Ziegler

Bio: J. F. Ziegler is an academic researcher from United States Naval Academy. The author has contributed to research in topics: Stopping power (particle radiation) & Dosimeter. The author has an hindex of 10, co-authored 19 publications receiving 5707 citations.

SRIM – The stopping and range of ions in matter (2010)

Abstract: SRIM is a software package concerning the S topping and R ange of I ons in M atter. Since its introduction in 1985, major upgrades are made about every six years. Currently, more than 700 scientific citations are made to SRIM every year. For SRIM-2010 , the following major improvements have been made: (1) About 2800 new experimental stopping powers were added to the database, increasing it to over 28,000 stopping values. (2) Improved corrections were made for the stopping of ions in compounds. (3) New heavy ion stopping calculations have led to significant improvements on SRIM stopping accuracy. (4) A self-contained SRIM module has been included to allow SRIM stopping and range values to be controlled and read by other software applications. (5) Individual interatomic potentials have been included for all ion/atom collisions, and these potentials are now included in the SRIM package. A full catalog of stopping power plots can be downloaded at www.SRIM.org . Over 500 plots show the accuracy of the stopping and ranges produced by SRIM along with 27,000 experimental data points. References to the citations which reported the experimental data are included.

SRIM-2008, Stopping Power and Range of Ions in Matter

Abstract: A - Description of program or function: SRIM is a group of programs which calculate the stopping and range of ions (10 eV - 2 GeV/amu) into matter. TRIM (the Transport of Ions in Matter) is the most comprehensive program included. TRIM will accept complex targets made of compound materials with up to eight layers, each of different materials. It will calculate both the final 3D distribution of the ions and also all kinetic phenomena associated with the ion's energy loss: target damage, sputtering, ionization, and phonon production. All target atom cascades in the target are followed in detail. It can be used for physics of recoil cascades, physics of sputtering, the stopping of ions in compounds and stopping powers for ions in gases; This included radiation damage from neutron, electrons and photons. SRIM-2008: 2008.03: Made changes to sputtering of targets Z=13 to 21 to omit discontinuity in treatment; Added Help buttons to TRIM plots, and included additional comments; Changed ordinate units for Ion/Recoil distributions to same as for Ions. 2008.02: Added Ordinate scales to ion trajectory plots; Removed bug in calc. for gas layers within solid targets; Added Chapters 8 and 9 from SRIM textbook to SRIM Help. 2008.01: No changes to basic calculation of SRIM-2003; Many small bugs have been corrected. This version of SRIM is consistent with the new SRIM Textbook (2008). Allows changes of Ion/Energy/Angle during calculation and added to previous TRIM results. SRIM-2006: 2006.01 No changes to basic calculation of SRIM-2003. This upgrade has the following changes: (1) You can now download the complete plots showing the experimental/theoretical stopping of any ion in any elemental target. This file is large (20 Mb+) but it contains over 22,000 experimental data points reported since 1899. These plots may be accessed using the button on the SRIM-2006 initial window. (2) The Error Message 'The number of recoils has exceeded SRIM memory' has been fixed. The fix has been tested for up to 1 M recoiling atoms in a recoil cascade from a single recoil event. Typically, you run into this problem when you use heavy ions with high energies, approaching a GeV, in which a single collision can transfer a large amount of energy, and the recoiling atom may generate up to a million further recoils. If the number of recoils exceeds the current TRIM memory allocation, the above error message will pop-up and explain how to enlarge the TRIM memory to fix the problem. The number of allowed recoils can be increased using the file: /Data/SRIM.cfg. This file contains instructions on how to increase the number of allowed recoils. (3) You can now make a file EXYZ.txt which shows the position of the incident ion at discrete energy points. For example, for Bi(500 keV) you can make a file showing its position at 100 keV increments. This option is at the bottom of the new TRIM input window, along with a Help and an example. (4) You can now enter individual damage energies for each atom in each layer. Hence, silicon in crystalline silicon can have different displacement and Binding energies that silicon in a separate SiO{sub 2} layer. This improves both damage calculations and sputtering calculations. (5) The TRIM output window 'SHOW LIVE DATA' has been improved. FYI, this is a button in the TRIM window during the calculation. It is on the upper left corner. I think most people do not know it exists, but some people find it very useful for ions with large recoil cascades. They can see what is going on. There has been no changes to the calculation of stopping power or ranges. B - Methods: It uses a full quantum mechanical treatment of ion-atom collisions (this manual refers to the moving atom as an 'ion', and all target atoms as 'atoms'). This calculation is made very efficient by the use of statistical algorithms which allow the ion to make jumps between calculated collisions and then averaging the collision results over the intervening gap. During the collisions, the ion and atom have a screened Coulomb collision, including exchange and correlation interactions between the overlapping electron shells. The ion has long range interactions creating electron excitations and plasmons within the target. These are described by including a description of the target's collective electronic structure and interatomic bond structure when the calculation is setup (tables of nominal values are supplied). The charge state of the ion within the target is described using the concept of effective charge, which includes a velocity dependent charge state and long range screening due to the collective electron sea of the target.

Solid State Microdosimetry With Heavy Ions for Space Applications

Abstract: This work provides information pertaining to the performance of Silicon-On-Insulator (SOI) microdosimeters in heavy ion radiation fields. SOI microdosimeters have been previously tested in light ion radiation fields for both space and therapeutic applications, however their response has not been established in high energy, heavy ion radiation fields which are experienced in space. Irradiations were completed at the NASA Space Radiation Laboratory at BNL using 0.6 GeV/u Fe and 1.0 GeV/u Ti ions. Energy deposition and lineal energy spectra were obtained with this device at various depths within a Lucite phantom along the central axis of the beam. The response of which was compared with existing proportional counter data to assess the applicability of SOI microdosimeters to future deployments in space missions.

Large Area Silicon Microdosimeter for Dosimetry in High LET Space Radiation Fields: Charge Collection Study

Abstract: Silicon microdosimeters for the characterisation of mixed radiation fields relevant to the space radiation environment have been under continual development at the Centre for Medical Radiation Physics for over a decade. These devices are useful for the prediction of single event upsets in microelectronics and for radiation protection of spacecraft crew. The latest development in silicon microdosimetry is a family of large-area n-SOI microdosimeters for real-time dosimetry in space radiation environments. The response of n-SOI microdosimeters to 2 MeV H and 5.5 MeV He ions has been studied to investigate their charge collection characteristics. The studies have confirmed 100% yield of functioning cells, but have also revealed a charge sharing effect due to diffusion of charge from events occurring outside the sensitive volume and an enhanced energy response due to the collection of charge created beneath the insulating layer. The use of a veto electrode aims to reduce collection of diffused charge. The effectiveness of the veto electrode has been studied via a coincidence analysis using IBIC. It has been shown that suppression of the shared events allows results in a better defined sensitive volume corresponding to the region under the core electrode where the electric field is strongest.

Characterization of a Novel Diamond-Based Microdosimeter Prototype for Radioprotection Applications in Space Environments

Abstract: This paper is dedicated to the characterization of a novel diamond microdosimeter prototype with 3D sensitive volumes produced by high energy boron implantation. Diamond has been chosen in order to further improve solid state based microdosimeter in terms of radiation hardness and tissue equivalency. IBIC measurements were undertaken to determine the charge collection efficiency map of the device. It was demonstrated that the proposed ion implantation technology allows for the formation of an array of well defined 3D SVs. A Geant4 application was developed to explain the effect of Al electrode thickness on observed anomaly in deposited energy. Specifics of the results and an update on the current status of the project is presented.

Ion acceleration by superintense laser-plasma interaction

Abstract: Ion acceleration driven by superintense laser pulses is attracting an impressive and steadily increasing effort. Motivations can be found in the applicative potential and in the perspective to investigate novel regimes as available laser intensities will be increasing. Experiments have demonstrated, over a wide range of laser and target parameters, the generation of multi-MeV proton and ion beams with unique properties such as ultrashort duration, high brilliance, and low emittance. An overview is given of the state of the art of ion acceleration by laser pulses as well as an outlook on its future development and perspectives. The main features observed in the experiments, the observed scaling with laser and plasma parameters, and the main models used both to interpret experimental data and to suggest new research directions are described.

On the use of SRIM for computing radiation damage exposure

Abstract: The SRIM (formerly TRIM) Monte Carlo simulation code is widely used to compute a number of parameters relevant to ion beam implantation and ion beam processing of materials. It also has the capability to compute a common radiation damage exposure unit known as atomic displacements per atom (dpa). Since dpa is a standard measure of primary radiation damage production, most researchers who employ ion beams as a tool for inducing radiation damage in materials use SRIM to determine the dpa associated with their irradiations. The use of SRIM for this purpose has been evaluated and comparisons have been made with an internationally-recognized standard definition of dpa, as well as more detailed atomistic simulations of atomic displacement cascades. Differences between the standard and SRIM-based dpa are discussed and recommendations for future usage of SRIM in radiation damage studies are made. In particular, it is recommended that when direct comparisons between ion and neutron data are intended, the Kinchin–Pease option of SRIM should be selected.

Results from 730 kg days of the CRESST-II Dark Matter search

Abstract: The CRESST-II cryogenic Dark Matter search, aiming at detection of WIMPs via elastic scattering off nuclei in CaWO4 crystals, completed 730 kg days of data taking in 2011. We present the data collected with eight detector modules, each with a two-channel readout; one for a phonon signal and the other for coincidently produced scintillation light. The former provides a precise measure of the energy deposited by an interaction, and the ratio of scintillation light to deposited energy can be used to discriminate different types of interacting particles and thus to distinguish possible signal events from the dominant backgrounds.

Results from 730 kg days of the CRESST-II Dark Matter Search

Abstract: The CRESST-II cryogenic Dark Matter search, aiming at detection of WIMPs via elastic scattering off nuclei in CaWO$_4$ crystals, completed 730 kg days of data taking in 2011. We present the data collected with eight detector modules, each with a two-channel readout; one for a phonon signal and the other for coincidently produced scintillation light. The former provides a precise measure of the energy deposited by an interaction, and the ratio of scintillation light to deposited energy can be used to discriminate different types of interacting particles and thus to distinguish possible signal events from the dominant backgrounds. Sixty-seven events are found in the acceptance region where a WIMP signal in the form of low energy nuclear recoils would be expected. We estimate background contributions to this observation from four sources: 1) "leakage" from the e/\gamma-band 2) "leakage" from the \alpha-particle band 3) neutrons and 4) Pb-206 recoils from Po-210 decay. Using a maximum likelihood analysis, we find, at a high statistical significance, that these sources alone are not sufficient to explain the data. The addition of a signal due to scattering of relatively light WIMPs could account for this discrepancy, and we determine the associated WIMP parameters.