Measurements of energy deposition from bremsstrahlung production as a function of angle and beam energy (5-25 MeV) are shown to be in excellent agreement with Monte Carlo predictions. Dosimetry measurements are made and predicted in both equilibrated and underequilibrated radiation environments. In the latter case the quality of the agreement requires an accurate prediction of both the photon and electron spectra produced by the primary electron beam. An improved empirical equation for predicting bremsstrahlung production is also presented. This empirical relation can be used to estimate doses without resorting to expensive calculational efforts. It also gives an analytical relationship for dose as a function of energy and angle for a converter optimized for bremsstrahlung production using 15.5 MeV electrons. >

Dose attenuation with depth in an absorber of on-axis bremsstrahlung generated from an electron target is measured. It is shown to agree within +or-9% with Monte Carlo predictions as a function of absorber material (Al, Fe, Pb) and incident electron-beam energy (5.5-25.1 MeV). For this on-axis bremsstrahlung, 1 to 5 g/cm/sup 2/ of upstream and 0.2 to 1 g/cm/sup 2/ of downstream Al buffer are sufficient to provide electron equilibration for CaF/sub 2/:Mn thermoluminescent dosimeters (TLDs) over the measured energy range of 5.5 to 25.1 MeV. Once effective equilibration has been established, an expression is given that can be used to predict the dose-area product per absorbed beam charge at a given incident beam energy in TLDs as a function of depth in absorbers, within a fixed solid angle centered about the beam axis. This expression is quantified for the measurements presented here. >

The radiation field from an intense reusable source of flash x-rays that delivers a measured peak dose and dose rate of 370 +/- 60 krad (CaF2) and (3.5 +/- 0.7) X 10(13) rad (CaF2)/s over a useful area of 80 cm2 is characterized. CaF2:Mn TLDs (thermoluminescent dosimeters), which are used to measure the dose field, are shown to be dose-rate independent within +/- 15% up to this level. Energy deposition in the CaF2 TLD chip was analyzed according to the origin of the electrons responsible for that deposition with a new computational tool.

The radiation field from an intense reusable source of flash X-rays that delivers a measured peak dose and dose rate of 370+or-60 krad (CaF/sub 2/) and (3.5 +or-0.7)*10/sup 13/ rad (CaF/sub 2/)/s over a useful area of 80 cm/sup 2/ is characterized. CaF/sub 2/:Mn TLDs (thermoluminescent dosimeters), which are used to measure the dose field, are shown to be dose-rate independent within +or-15% up to...

The radiation produced by a 15.5-MeV monoenergetic electron beam incident on optimized and non-optimized bremsstrahlung targets is characterized using the ITS Monte Carlo code and measurements with equilibrated and non-equilibrated TLD dosimetry. Comparisons between calculations and measurements verify the calculations and demonstrate that the code can be used to predict both bremsstrahlung production and TLD response for radiation fields that are characteristic of those produced by pulsed simulators of gamma rays. At optimum bremsstrahlung production, the predicted total forward radiation fluence detected in equilibrated TLD dosimetry agrees with that measured within the +/- 6% uncertainty of the measurement. The absolute comparisons made here provide independent confirmation of the validity of the TLD calibration for photon fields characteristic of gamma-ray simulators. The empirical Martin equation, which is often used to calculate radiation dose from optimized bremsstrahlung targets, is examined, and its range of validity is established from the data presented.

Measurements of energy deposition as a function of equilibrator thickness and position in the HERMES III radiation field are compared to ITS code predictions. These measurements demonstrate the combined photon/electron nature of the radiation field and the importance of the electron field in both measurements and calculations.

Radiation-induced upset levels in SA3001 static random access memories (SRAMs) and SA3246 clock integrated circuits (ICs) have been measured in a medium-energy flash X-ray environment (average photon energy approximately 100 keV), where dose-enhancing effects are very important. By comparing device responses using a non-dose-enhancing ceramic package lid and a dose-enhancing Kovar/gold lid, dose-enhancement factors for photocurrent and upset were generated. The observed upset enhancement factors of 3.0+or-0.5 (SRAM) and 2.2+or-0.2 (clock IC) are in excellent agreement with measurements of photocurrent enhancement factors (2.5+or-0.5) in diodes processed with the same diffusions as the complementary metal-oxide-semiconductor (CMOS) ICs irradiated in a steady-state X-ray environment. These results indicate that upset is dominated by the radiation-induced transient supply current in these ICs, and that steady-state diode photocurrent measurements are a good predictor of both photocurrent and upset enhancement for ICs made with this technology. >

The bremsstrahlung field from an extended planar-anode diode with an annular cathode tip on the the 16-TW HERMES III electron accelerator is measured and compared with predictions of the MAGIC-CYLTRAN model. Measurements confirm predictions and demonstrate that the diode provides a versatile large-area source of gamma radiation. Versatility is obtained by adjustment of the anode-cathode gap, which...

Pulse-height distributions in two different types of Ge detectors have been measured for a variety of medium-energy X-ray bremsstrahlung spectra. These measurements have been compared to predictions using the Integrated Tiger Series (ITS) Monte Carlo electron/photon transport code. In general, the authors find excellent agreement between experiments and predictions using no free parameters. These ...

The response of MOS capacitors with TaSi/Al and Al electrodes to medium- and low-energy x-irradiation is investigated. Experimentally measured dose-enhancement effects are compared with computer simulations for these structures.

Responses of a Ge detector and a filtered thermoluminescent dosimeter (TLD) array detector were measured at a steady-state bremsstrahlung source (the Pelletron), at endpoint energies from 150 to 900 keV. Predictions of detector response using the Integrated Tiger Series (ITS) Monte Carlo codes are found to be in excellent agreement with measured responses for both detectors. The results extend the...