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1.
We present an investigation of gamma and neutron radiation effects on mica film capacitors from an electrical point of view.
We have studied quantitatively the effects of gamma and neutron irradiation on mica film capacitors of thickness, 20 and 40
μm (0.7874 and 1.5748 mil) with two different areas, 01 and 04 cm2. The capacitance has been measured at room temperature in the frequency range 100 Hz-10 MHz. Negligible change in the capacitance
due to high gamma dose of60Co, 15 kGy at dose rate 0.25 kGy/h, has been observed. However, appreciable change in the capacitance has been observed due
to low doses of fast neutrons (cumulative dose, 115 cGy) with flux ∼ 9.925 x 107 neutrons/cm2 h from252Cf neutron source of fluence, 2.5 × 107 neutrons/s. We have also observed that the impact of gamma and neutron irradiation is more at frequencies higher than 10
kHz. These results show that the mica capacitors do not show any radiation response below 10 kHz.
The study shows the radiation response of mica film capacitors to gamma and fast neutron radiations. Mica capacitors show
low gamma radiation response in comparison to fast neutron radiation, because a total dose of kGy order has been given by
gamma source and only few cGy dose has been given by fast neutron source. 相似文献
2.
Garima Agarwal Ankur Jain Shivani Agarwal D. Kabiraj I. P. Jain 《Bulletin of Materials Science》2006,29(2):187-191
Synthesis of swift heavy ion induced metal silicide is a new advancement in materials science research. We have investigated
the mixing at Co/Si interface by swift heavy ion beam induced irradiation in the electronic stopping power regime. Irradiations
were undertaken at room temperature using 120 MeV Au ions at the Co/Si interface for investigation of ion beam mixing at various
doses: 8 × 1012, 5 × 1013 and 1 × 1014 cm−2. Formation of different phases of cobalt silicide is identified by the grazing incidence X-ray diffraction (GIXRD) technique,
which shows enhancement of intermixing and silicide formation as a result of irradiation.I–V characteristics at Co/Si interface were undertaken to understand the irradiation effect on conduction mechanism at the interface. 相似文献
3.
Multiharmonic ac-magnetic susceptibilityx
1,x
2,x
3, of neutron irradiated Li-doped YBa2Cu3O7−x
has revealed a nonmonotonic dependence of all harmonics on the neutron fluence. The irradiation has a strongly depressive
influence on the intergrain connection suggesting an increase of the effective thickness of the intergranular Josephson junction
at a neutron fluence of 0.98 × 1017 cm−2. Less damaged are the intragrain properties. A spectacular enhancement of the superconducting intragranular properties reflected
in the characteristics of all harmonics was observed at highest fluence φ=9.98 × 1017 cm−2. We assume that this effect results from the development of a space inhomogeneous distribution with alternating defectless
and defect-rich regions. 相似文献
4.
Vaibhav Kulshrestha K. Awasthi N. K. Acharya M. Singh Y. K. Vijay 《Bulletin of Materials Science》2005,28(7):643-646
In the present study the polyethersulphone (PES) membranes of thickness (35 ±2) μm were prepared by solution cast method.
The permeability of these membranes was calculated by varying the temperature and by irradiation of α ions. For the variation
of temperature, the gas permeation cell was dipped in a constant temperature water bath in the temperature range from 303–373
K, which is well below the glass transition temperature (498 K). The permeability of H2 and CO2 increased with increasing temperature. The PES membrane was exposed by a-source (95Am241) of strength (1 μ Ci) in vacuum of the order of 10−6 torr, with fluence 2.7 × 107 ions/cm2. The permeability of H2 and CO2 has been observed for irradiated membrane with increasing etching time. The permeability increases with increasing etching
time for both gases. There was a sudden change in permeability for both the gases when observed at 18 min etching. At this
stage the tracks are visible with optical instrument, which confirms that the pores are generated. Most of pores seen in the
micrograph are circular cross-section ones. 相似文献
5.
C. Yürdü S. Işçi C. Ünlü O. Atici Ö. I. Ece N. Güngör 《Bulletin of Materials Science》2005,28(6):623-628
In this study, the rheologic and colloidal characterizations of sodium montmorillonite (NaMMT) were examined. Hexadecylamine
(CH3(CH2)15NH2, HDA) was added to the bentonite water dispersion (2%, w/w) in different concentrations in the range 5.6 × 10−4−9.4 × 10−3 mmol/l. The rheological and electrokinetic behaviour of aqueous montmorillonite dispersions was investigated as a function
of solid content and HDA concentration. The basal spacings of the HDA/NaMMT composites were studied by X-ray diffraction.
The FTIR spectra were obtained from the modified bentonite products, which revealed the characteristic absorbances after treatment
with HDA. 相似文献
6.
Multiharmonic ac-magnetic susceptibility χ1, χ2, χ3, of neutron irradiated Li-doped YBa2Cu3O7−
x
has revealed a nonmonotonic dependence of all harmonics on the neutron fluence. The irradiation has a strongly depressive
influence on the intergrain connection suggesting an increase of the effective thickness of the intergranular Josephson junction
at a neutron fluence of 0.98 × 1017 cm−2. Less damaged are the intragrain properties. A spectacular enhancement of the superconducting intragranular properties reflected
in the characteristics of all harmonics was observed at highest fluence Φ = 9.98 × 1017 cm−2. We assume that this effect results from the development of a space inhomogeneous distribution with alternating defectless
and defect-rich regions. 相似文献
7.
10B isotope doped p-type diamond epilayer grown by chemical vapor deposition on (110) oriented type IIa diamond single crystal
substrate was subjected to neutron transmutation at a fluence of 2.4 × 1020 thermal and 2.4 × 1020 fast neutrons. After neutron irradiation, the epilayer and the diamond substrate were laser annealed using Nd–YAG laser irradiation
with wave length, 266 nm and energy, 150 mJ per pulse. The neutron irradiated diamond epilayer and the substrate were characterized
before and after laser annealing using different techniques. The characterization techniques include optical microscopy, secondary
ion mass spectrometry, X-ray diffraction, Raman, photoluminescence and Fourier Transform Infrared spectroscopy, and electrical
sheet conductance measurement. The results indicate that the structure of the irradiation induced amorphous epilayer changes
to disordered graphite upon laser annealing. The irradiated substrate retains the (110) crystalline structure with neutron
irradiation induced defects. 相似文献
8.
《Vacuum》2012,86(3):275-279
We have investigated neutron irradiation effects on the optical, structural and chemical properties of polyallyl diglycol carbonate (PADC) polymer, commercially named as CR-39. For this purpose, PADC samples were exposed with 4 MeV Am–Be neutron source at fluences varying from 2.36 × 106 to 5.94 × 107 n/cm2. The modifications so induced were analyzed using UV–Visible spectroscopy, X-ray diffraction Measurement (XRD), Photoluminescence (PL) and Fourier Transform infrared (FTIR) spectroscopy in the total attenuation reflection (ATR) mode. UV–Vis spectra of pristine and neutron irradiated PADC polymer sheets exhibit a decreasing trend in optical band gap. This decline in optical band gap with increasing fluence has been discussed on the basis of neutron irradiation induced defects in PADC. The XRD pattern of PADC shows the decreasing intensity of peak positions with increasing in fluence, which suggest that semicrystallinity of PADC changes slightly to amorphous phase after irradiation. At low fluence, crystallinity was found to increase but at higher fluence, it decreased which could be ascribed to neutron- induced defects in the polymer samples. Crystallite size calculated using Scherrer formula indicates a change and reflects the formation of disordered system in the irradiated polymer samples. The PL spectra show that the intensity of PL peak decreased with increase in fluence, which may be due to the disordered system via creation of defects in the irradiated polymer. The FTIR spectrum shows an overall reduction in intensity of the typical bands, indicating the degradation of PADC polymer after irradiation. These results so obtained can be used successfully in dosimetery using well reported protocols. 相似文献
9.
C. A. Londos G. D. Antonaras M. S. Potsidi D. N. Aliprantis A. Misiuk 《Journal of Materials Science: Materials in Electronics》2007,18(7):721-728
Experimental data of infrared (IR) absorption measurements carried out on fast neutron irradiated carbon rich Cz–Si crystals
were studied. Data from similar crystals, subjected prior to irradiation to thermal treatments at 1000 °C [(HT)] and thermal
treatments at 1000 °C under high hydrostatic pressure [(HTHP)] of 11Kbar, were also studied. The time duration of both treatments
was 5 h. After the irradiation the intensities of most of the observed bands were always stronger in the pre-treated material.
Transformation of the defects upon post-irradiation isochronal anneals was investigated. Two out of six IR bands of the CiCs defect in the neutral charge state, at 543.5 and 635 cm−1, were detected at room temperature [(RT)]. It is argued that another two bands at 918 and 1006 cm−1 arising in the spectra upon annealing of the CiCs bands are associated with the same carbon-related structure giving rise to the Si-PT4 electron paramagnetic resonance (EPR)
spectrum. A band at 533 cm−1 shows the same thermal evolution with a defect giving rise to the Si-P6 EPR spectrum attributed to a multi-interstitial cluster
in silicon. Differences observed in the evolution curves of the CiCs(SiI) defect (987, 993 cm−1) between the as-grown and the pre-treated samples are considered and discussed. 相似文献
10.
G. K. R. Senadeera S. Kobayashi T. Kitamura Y. Wada S. Yanagida 《Bulletin of Materials Science》2005,28(6):635-641
Nano-structured TiO2 electrodes, suitable for dye sensitized solid-state solar cells were prepared by a new simple spraying technique (SPT). Physical
properties of these electrodes were compared with the electrodes prepared by the ‘doctor blade’ technique (typical sliding
method, DB). Dye sensitized solid-state solar cells, comprising of CuI as the hole conductor, were fabricated with these electrodes
and enhanced photo responses were obtained with SPT electrodes. The effects of additives, either to the spray solution or
to the hole conductor on the photoresponses of the above devices were also studied. The cells fabricated with SPT electrodes
containing Al(BuiO)3 showed ∼ 2.4% efficiency and addition of 1-ethyl-3-methyl imidazolium thiocyanate into CuI layer further enhanced the efficiency
up to 2.75% under the irradiance of 100 mW cm−2 (AM 1.5). 相似文献
11.
K. R. Nagabhushana B. N. Lakshminarasappa Fouran Singh 《Bulletin of Materials Science》2009,32(5):515-519
Polycrystalline aluminum oxide is synthesized by combustion technique and XRD studies of the sample revealed the α-phase. The synthesized sample is irradiated with 120 MeV swift Au9+ ions for the fluence in the range from 1 × 1011 to 1 × 1013 ions cm−2. A broad photoluminescence (PL) emission with peak at ∼ 447 nm and two sharp emissions with peak at ∼ 679 and ∼ 695 nm are
observed in pristine when sample was excited with 326 nm. However, in the irradiated samples the PL intensity at ∼ 447, 679
and 695 nm decreases with increase in ion fluence. The α-Al2O3 gives rise to seven Raman modes with Raman intensity with peaks at ∼ 253, 396, 417, 546, 630, 842, 867 cm−1 observed in pristine. The intensity of these modes decreases with increase in ion fluence. However, the Raman modes observed
at lower fluences are found to disappear at higher fluence. 相似文献
12.
Gorshkov O. N. Pavlov D. A. Trushin V. N. Antonov I. N. Shenina M. E. Bobrov A. I. Markelov A. S. Dudin A. Yu. Kasatkin A. P. 《Technical Physics Letters》2012,38(2):185-187
The investigation of bulk single crystals and sputter-deposited films of yttria-stabilized zirconia (YSZ) upon irradiation
by gold (Au) ions with an average energy of 160 keV followed by postimplantation annealing revealed peculiarities in the formation
of nanocrystalline metal (nc-M) particles in this matrix. In the case of irradiation to small doses (∼5 × 1015 cm−2), the optical absorption spectra of samples showed evidence of the formation of nanoclusters of matrix cations (nc-Zr). In
these samples, postimplantation annealing at temperatures ∼700°C and above leads to the formation of nc-Au particles. Local
elemental analysis of individual nc-M particles in the YSZ matrix irradiated to a dose of 4 × 1016 cm−2 and annealed at 800°C showed the presence of metal nanoparticles with complex compositions including both implanted Au and
matrix Zr atoms. 相似文献
13.
N. Srinivasa Rao Shashidhar Bale M. Purnima K. Siva Kumar Syed Rahman 《Bulletin of Materials Science》2005,28(6):589-592
The local structure around Cu2+ ion has been examined by means of electron spin resonance and optical absorption measurements in xLi2O-(40-x)Na2O-50B2O3-10As2O3 glasses. The site symmetry around Cu2+ ions is tetragonally distorted octahedral. The ground state of Cu2+ isd
x
2−y
2.The glass exhibited broad absorption band near infrared region and small absorption band around 548 nm, which was assigned
to the
2B1g →2Eg
transition. 相似文献
14.
Single crystals of calcium hydrazine carboxylate, monohydrate have been studied by ESR of Mn2+ doped in the calcium sites. X-band ESR indicated a large crystal field splitting necessitating experiments at Q band. The
analysis shows two magnetically inequivalent (but chemically equivalent) sites withg
xx = 2.0042±0.0038,g
yy=2.0076 ±0.0029,g
zz=2.0314±0.001,A
zz=0.0099±0.0002 cm−1,A
xx=0.0092±0.0002 cm−1,A
yy=0.0082±0.0002 cm−1,D=3/2D
zz=0.0558±0.0006 cm−1, andE=1/2 (D
yy−D
yy)=0.0127±0.0002 cm−1.
One of the principal components of the crystal field, (D
zz), is found to be along the Ca ↔ Ca direction in the structure and a second one, (D
xx), along the perpendicular to the plane of the triangle formed by three neighbouring calciums. TheA tensor is found to have an orientation different from that of theg andD tensors reflecting the low symmetry of the Ca2+ sites. 相似文献
15.
Irradiation effects of a 3 MeV proton beam on polycarbonate (makrofol-DE (MFD)) have been studied with respect to its electrical,
thermal and structural behaviour by using an LCR meter, DSC/TGA and FTIR spectroscopy. The dielectric loss/constant was observed
to change with the fluence. Thermal analysis revealed that chain scission is the dominant phenomena in irradiated samples
based on the reduction of its thermal stability by about 19% at a fluence of 1015 ions/cm2, which is also corroborated by FTIR spectra. No significant change in intensity of the absorbance bands of the irradiated
sample was observed up to a fluence of 1014 ions/cm2 while on increasing fluence (1015 ions/cm2) the polymer structure was modified. It appears from DSC thermograms thatT
g is observed to change with fluence. 相似文献
16.
Processes of laser implantation of shallow donors (aluminum and indium) and an acceptor (antimony) in CdTe crystals (n,p∼1015 cm−3) are investigated. Thin dopant films vacuum deposited on the etched surface of the crystals are irradiated by ruby (λ=0.694
μm) and Nd:YAG (λ=1.06 μm) laser pulses (pulse duration 20 ns) over a wide energy interval (0.1–1.8 J/cm2). The irradiated surfaces are studied by x-ray microanalysis, Auger spectroscopy, and the thermopower method. It is it is
shown that irradiation by a Nd:YAG laser produces a uniform doping of a subsurface layer of the crystal by aluminum. The implantation
of indium leads to the formation of a precipitate. The concentration of implanted impurities reaches 1019–1021 cm−3.
Pis’ma Zh. Tekh. Fiz. 24, 1–6 (June 12, 1998) 相似文献
17.
Z. V. Jibuti N. D. Dolidze N. Sikhuashvili G. L. Eristavi 《Technical Physics Letters》2004,30(9):730-731
We have studied the effect of neutron irradiation on the microhardness of n-GaAs crystals. It is shown that the growth and saturation of microhardness with increasing radiation dose Φ, as previously
reported in the literature, take place only in the dose range Φ∼1015−5×1016 cm−2. As the neutron dose is increased further, the microhardness continues to grow due to the increasing role of the radiation-induced
disordered regions in n-GaAs. 相似文献
18.
Semi-insulating <111> ZnTe prepared by In doping during Bridgman growth was found to have a resistivity of 5.74 × 107 ohm-cm, the highest reported so far in ZnTe, with hole concentration of 2.4 × 109/cm3 and hole mobility of 46 cm2 /V.s at 300 K. The optical band gap was 2.06 eV at 293 K compared with 2.26 eV for undoped semiconducting ZnTe. Thermally
stimulated current (TSC) studies revealed 2 trap levels at depths of 202–222 meV and 412–419 meV, respectively. Photoluminescence
(PL) studies at 10 K showed strong peaks at 1.37 eV and 1.03 eV with a weak shoulder at 1.43 eV. Short anneal for 3 min at
250°C led to conversion to a p-type material with resistivity, 14.5 ohm-cm, indicating metastable behaviour. Raman studies
carried out on undoped and In-doped samples showed small but significant differences. Possible models for semi-insulating
behaviour and meta-stability are proposed. 相似文献
19.
The present work deals with the mixing of iron and silicon by swift heavy ions in high-energy range. The thin film was deposited
on a n-Si (111) substrate at 10−6 torr and at room temperature. Irradiations were undertaken at room temperature using 120 MeV Au+9 ions at the Fe/Si interface to investigate ion beam mixing at various doses: 5 × 1012 and 5 × 1013 ions/cm2. Formation of different phases of iron silicide has been investigated by X-ray diffraction (XRD) technique, which shows enhancement
of intermixing and silicide formation as a result of irradiation. I-V measurements for both pristine and irradiated samples have been carried out at room temperature, series resistance and barrier
heights for both as deposited and irradiated samples were extracted. The barrier height was found to vary from 0·73–0·54 eV.
The series resistance varied from 102·04–38·61 kΩ. 相似文献
20.
The first investigations have been made on the diffusion of promethium in silicon. In the temperature range from 1100 to 1250
°C the diffusion constant of promethium increases from ∼1×10−13 cm2/s to ∼1.5×10−12 cm2/s. The temperature dependence of the diffusion coefficient can be described by D = 5 x 10−1 exp[-(3.3 eV/kT]cm2/s.
Pis’ma Zh. Tekh. Fiz. 23, 46–50 (January 26, 1997) 相似文献