scholarly journals Comparison of gamma ray effects on EPROMs and E2PROMs

2009 ◽  
Vol 24 (1) ◽  
pp. 61-67 ◽  
Author(s):  
Milos Vujisic ◽  
Koviljka Stankovic ◽  
Aleksandra Vasic
Keyword(s):  
Gamma Rays ◽  
Gamma Ray ◽  
Radiation Hardness ◽  
The Other ◽  
Other Hand ◽  
Read Only Memory ◽  
Ray Effects

This paper compares the reliability of standard commercial Erasable Programmable Read Only Memory (EPROM) and Electrically Erasable Programmable Read Only Memory (E2PROM) components exposed to gamma rays. The results obtained for CMOS-based EPROM (NM27C010) and E2PROM (NM93CS46) components provide the evidence that EPROMs have greater radiation hardness than E2PROMs. Moreover, the changes in EPROMs are reversible, and after erasure and reprogramming all EPROM components restore their functionality. On the other hand, changes in E2PROMs are irreversible. The obtained results are analyzed and interpreted on the basis of gamma ray interaction with the CMOS structure.

scholarly journals Gamma Ray-Induced Polymerization and Cross-Linking for Optimization of PPy/PVP Hydrogel as Biomaterial

Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 111 ◽  
Author(s):  
Jin-Oh Jeong ◽  
Jong-Seok Park ◽  
Young-Ah Kim ◽  
Su-Jin Yang ◽  
Sung-In Jeong ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Cell Viability ◽  
Gamma Rays ◽  
Biomedical Applications ◽  
Gamma Ray ◽  
The Other ◽  
Cross Linking ◽  
Gamma Ray Irradiation ◽  
Good Cell ◽  
Scanning Electron

Conducting polymer (CP)-based hydrogels exhibit the behaviors of bending or contraction/relaxation due to electrical stimulation. They are similar in some ways to biological organs and have advantages regarding manipulation and miniaturization. Thus, these hydrogels have attracted considerable interest for biomedical applications. In this study, we prepared PPy/PVP hydrogel with different concentrations and content through polymerization and cross-linking induced by gamma-ray irradiation at 25 kGy to optimize the mechanical properties of the resulting PPy/PVP hydrogel. Optimization of the PPy/PVP hydrogel was confirmed by characterization using scanning electron microscopy, gel fraction, swelling ratio, and Fourier transform infrared spectroscopy. In addition, we assessed live-cell viability using live/dead assay and CCK-8 assay, and found good cell viability regardless of the concentration and content of Py/pTS. The conductivity of PPy/PVP hydrogel was at least 13 mS/cm. The mechanical properties of PPy/PVP hydrogel are important factors in their application for biomaterials. It was found that 0.15PPy/PVP20 (51.96 ± 6.12 kPa) exhibited better compressive strength than the other samples for use in CP-based hydrogels. Therefore, it was concluded that gamma rays can be used to optimize PPy/PVP hydrogel and that biomedical applications of CP-based hydrogels will be possible.

scholarly journals EVIDENCE FOR A PHOTON MASS

2010 ◽  
Vol 19 (07) ◽  
pp. 1341-1347 ◽  
Author(s):  
B. G. SIDHARTH
Keyword(s):  
Power Spectrum ◽  
Gamma Rays ◽  
Time Lag ◽  
The Other ◽  
Photon Mass ◽  
The Past ◽  
A Value ◽  
Other Hand ◽  
Wmap Data

Recently Spavieri and Rodriguez had proposed a table top experiment using Aharanov–Bohm type effects to determine the mass of a photon and concluded that a value as small as 10-51 g is achievable. It is pointed out in this paper that this value is already much higher than latest experimental limits. Furthermore, the author's work over the past years has, on the other hand, indicated that the photon has a mass ~10-65 g = 10-33 eV . We point out in this papers that recent observations from three different viewpoints, which are not table top experiments, but rather the time lag in cosmic gamma rays with different frequencies, the observation of the spectra of blazars and an analysis of the CMB power spectrum from the WMAP data, all vindicate this conclusion and remarkably, this value.

scholarly journals Gamma-Ray Lines from Solar Flares

1975 ◽  
Vol 68 ◽  
pp. 363-383 ◽  
Author(s):  
R. Ramaty ◽  
R. E. Lingenfelter
Keyword(s):  
Gamma Rays ◽  
Solar Flares ◽  
Neutron Capture ◽  
Gamma Ray ◽  
Nuclear Reactions ◽  
The Other ◽  
Line Production ◽  
Absolute Intensities ◽  
Flare Region ◽  
Accelerated Particles

We have treated in detail the theory of gamma-ray line production in solar flares. The strongest line, both predicted theoretically and detected observationally at 2.2 MeV, is due to neutron capture by protons in the photosphere. The neutrons are produced in nuclear reactions of flare accelerated particles which also produce positrons and prompt nuclear gamma rays. From the comparison of the observed and calculated intensities of the lines at 4.4 or 6.1 MeV to that of the 2.2 MeV line it is possible to deduce the spectrum of accelerated nuclei in the flare region; and from the absolute intensities of these lines it is possible to obtain the total number of accelerated nuclei at the Sun. The study of the 2.2 MeV line also gives information on the amount of He3 in the photosphere. The study of the line at 0.51 MeV resulting from positron annihilation complements the data obtained from the other lines; in addition it gives information on the temperature and density in the annihilation region and on the anisotropy of the accelerated electron beam which produces continuum gamma rays at energies greater than about 1 MeV.

Angular Distribution of Gamma-Ray Bursts: An Observational Probe of Cosmological Principle

2005 ◽  
Vol 201 ◽  
pp. 486-487
Author(s):  
Attila Mészáros ◽  
Lajos G. Balázs ◽  
Roland. Vavrek ◽  
István Horváth ◽  
Zsolt. Bagoly
Keyword(s):  
Angular Distribution ◽  
Confidence Level ◽  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
The Other ◽  
Final Conclusion ◽  
Instrumental Effects ◽  
Cosmological Principle ◽  
Other Hand

The test of the isotropy in the angular distribution of the gamma-ray bursts collected in BATSE Catalog (Meegan C. A. et al. 2000) is a test of cosmological principle itself, because the gamma-ray bursts are at cosmological distances. Several articles of the authors study this question (Balázs L. G., Mészáros A., & Horváth I., Astron. Astrophys., 339, 1, 1998; Balázs L. G., Mészáros A., Horváth I., & Vavrek R., Astron. Astrophys. Suppl., 138, 417, 1999; Mészáros A., Bagoly Z., & Vavrek R. Astron. Astrophys., 354, 1, 2000; Mészáros A., Bagoly Z., Horváth I., Balázs L.G. & Vavrek R. Astrophys. J., 539, 98, 2000). The final conclusion concerning the validity of isotropy is complicated both by instrumental effects and by the fact that there are three subgroups of gamma-ray bursts (“short”, “intermediate”, “long”; separation is done with respect to the duration of bursts). The long bursts are surely up to z ⋍ 4 (z is the redshift); for the remaining two subclasses the redshifts are unknown. The done tests of isotropy suggest (after the elimination of instrumental effects) the existence of anisotropy for the intermediate subclass on the confidence level > 95%. On the other hand, for the remaining two subclasses the situation is unclear; there is no unambiguous rejection of isotropy for them yet on the higher than 95% confidence level. If the bursts of intermediate subclass are at high z-s (say, at z > 0.1), then the validity of cosmological principle would be in serious doubt.

scholarly journals Gamma ray effects on flash memory cell arrays

2012 ◽  
Vol 27 (3) ◽  
pp. 284-289 ◽  
Author(s):  
Edin Dolicanin
Keyword(s):  
Gamma Rays ◽  
Flash Memory ◽  
Gamma Ray ◽  
Memory Cell ◽  
Floating Gate ◽  
Data Retention ◽  
Flash Memories ◽  
Cell Arrays ◽  
Flash Memory Cell ◽  
Ray Effects

Information stored in flash memories is physically represented by the absence or presence of charge on electrically isolated floating gates. Interaction of gamma rays with the insulators surrounding the floating gate produces effects that degrade the properties of memory cells, possibly leading to the corruption of the stored content. The cumulative nature of these effects is expressed through the total ionizing dose deposited by the gamma rays in the insulators surrounding the floating gate. Relying on both theory and experiment, we examine how the properties of cells in commercially available flash memories affect their sensitivity to gamma rays. Memory samples from several manufacturers, currently available on the market, can be compared with respect to data retention under gamma ray exposure.

Gamma-ray burst measurements at low fluxes

1981 ◽  
Vol 301 (1462) ◽  
pp. 661-663
Keyword(s):  
Power Law ◽  
Gamma Ray ◽  
The Other ◽  
Source Distribution ◽  
Gamma Ray Burst ◽  
Thick Disc ◽  
Other Hand ◽  
Source Models ◽  
Arrival Directions

Recent measurements of the number of cosmic y-ray bursts per year at small flux levels continue to show significant deviations from the N (> S ) S -3/2 power law for the rate N ( > S ) at size S which would apply to a uniform source distribution. In particular Fishman et al. (1978) and Agrawal et al. (1979) find flux limits two orders of magnitude lower than those expected when the Vela (Strong & Klebesadel 1974) data are extrapolated by the S -3/2 -law to flux levels 5 x 10 -8 erg cm -2 . Spherical halo, monoluminosity source distributions discussed by Jennings & White (1980) have failed to satisfy these data although they are consistent with triangulation results obtained by spacecraft networks on a few individual burst arrival directions (Hurley 1980). On the other hand, thick disc source models seem to satisfy the observed lg N -lg S distribution.

On the possible gamma-ray source in Cygnus

1967 ◽  
Vol 31 ◽  
pp. 469-471
Author(s):  
J. G. Duthie ◽  
M. P. Savedoff ◽  
R. Cobb
Keyword(s):  
Gamma Rays ◽  
Gamma Ray ◽  
Right Ascension

A source of gamma rays has been found at right ascension 20h15m, declination +35°, with an uncertainty of 6° in each coordinate. Its flux is (1·5 ± 0·8) x 10-4photons cm-2sec-1at 100 MeV. Possible identifications are reviewed, but no conclusion is reached. The mechanism producing the radiation is also uncertain.

Solar Flare Energetic Neutral Emission Measurements in the Project Coronas-I

1994 ◽  
Vol 144 ◽  
pp. 635-639
Author(s):  
J. Baláž ◽  
A. V. Dmitriev ◽  
M. A. Kovalevskaya ◽  
K. Kudela ◽  
S. N. Kuznetsov ◽  
...  
Keyword(s):  
Solar Flare ◽  
Energy Range ◽  
Gamma Rays ◽  
Pulse Shape ◽  
Gamma Ray ◽  
Pulse Shape Discrimination ◽  
Shape Discrimination ◽  
Solar Neutron ◽  
Low Altitude

AbstractThe experiment SONG (SOlar Neutron and Gamma rays) for the low altitude satellite CORONAS-I is described. The instrument is capable to provide gamma-ray line and continuum detection in the energy range 0.1 – 100 MeV as well as detection of neutrons with energies above 30 MeV. As a by-product, the electrons in the range 11 – 108 MeV will be measured too. The pulse shape discrimination technique (PSD) is used.

A study of cometary eruptions through OH radio-lines

1999 ◽  
Vol 173 ◽  
pp. 249-254
Author(s):  
A.M. Silva ◽  
R.D. Miró
Keyword(s):  
Short Duration ◽  
Growth Curves ◽  
The Other ◽  
Initial Mass ◽  
Radio Lines ◽  
Other Hand ◽  
Sudden Rise

AbstractWe have developed a model for theH2OandOHevolution in a comet outburst, assuming that together with the gas, a distribution of icy grains is ejected. With an initial mass of icy grains of 108kg released, theH2OandOHproductions are increased up to a factor two, and the growth curves change drastically in the first two days. The model is applied to eruptions detected in theOHradio monitorings and fits well with the slow variations in the flux. On the other hand, several events of short duration appear, consisting of a sudden rise ofOHflux, followed by a sudden decay on the second day. These apparent short bursts are frequently found as precursors of a more durable eruption. We suggest that both of them are part of a unique eruption, and that the sudden decay is due to collisions that de-excite theOHmaser, when it reaches the Cometopause region located at 1.35 × 105kmfrom the nucleus.

Closing the GAP—A 5Å Scanning Microscope

1969 ◽  
Vol 27 ◽  
pp. 6-7
Author(s):  
A. V. Crewe
Keyword(s):  
Normal Form ◽  
The Other ◽  
Resolving Power ◽  
Scanning Microscope ◽  
Conventional Microscope ◽  
Other Hand ◽  
Closing The Gap ◽  
Thermal Sources ◽  
Better Than ◽  
Transmission Microscope

We have become accustomed to differentiating between the scanning microscope and the conventional transmission microscope according to the resolving power which the two instruments offer. The conventional microscope is capable of a point resolution of a few angstroms and line resolutions of periodic objects of about 1Å. On the other hand, the scanning microscope, in its normal form, is not ordinarily capable of a point resolution better than 100Å. Upon examining reasons for the 100Å limitation, it becomes clear that this is based more on tradition than reason, and in particular, it is a condition imposed upon the microscope by adherence to thermal sources of electrons.

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