I. B. Berlman

Argonne National Laboratory, Lemont, Illinois, United States

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Publications (21)39.16 Total impact

  • I. B. Berlman · O. J. Steingraber
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    ABSTRACT: A systematic study has been made of some of the processes that contribute to the scintillation pulse shape, and this knowledge has been applied to pulse-shape discriminating solutions. The results indicate that pulse-shape discrimination is enhanced by materials that have a high phosphorescence yield and large radiative lifetime. Quarternary solutions have been developed that have a larger average pulse height and better discrimination efficiency than the commercial solution NE-213. The efficiency of discrimination is generally reduced by compounds that are susceptible to excimer formation. Yet, excimer emission in certain solvents can be used to advantage to invert the normal results and to obtain pulse contours produced by electrons, that have a larger percentage of long component radiation than pulses generated by α-particles. This latter type of solution may also be useful in differentiating between low energy β-particles and tube noise.
    No preview · Article · May 1973 · Nuclear Instruments and Methods
  • I. B. Berlman · O. J. Steingraber
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    ABSTRACT: Apparatus for accurately recording scintillation pulse contours is described and sample pulse shapes for excitation by α and β particles are presented. A favorable characteristic of this equipment is that it can reproduce the scintillation pulse with high fidelity in about 15 min. This equipment is well suited for studies of solutions to be used in pulse-shape discrimination and for studies of dynamic quenching.
    No preview · Article · Jan 1973 · Nuclear Instruments and Methods
  • Isadore B. Berlman · Hermann O. Wirth · O. J. Steingraber
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    ABSTRACT: The fluorescence characteristics (lifetime, quantum yield, Stokes loss, spectral width, etc.) of about 20 variously substituted and bridged p-oligophenylenes have been systematically investigated so that the relationship between molecular structure and these characteristics would be better understood. When alkyl chains are employed as substituents to enhance the solubility of a compound, it is important that these substituents be placed in the proper positions, for when in the para or meta positions of terminal rings, their effect on the fluorescence characteristics is minimal, but when placed on the ortho position of the terminal rings or on the meta and ortho positions of the phenylene rings, certain characteristics such as quantum yield are adversely affected by steric crowding. Moreover, an alkyloxy group substituted on the para position will enhance the permanent dipole moment and the molar extinction coefficient. These studies support the contention that the fluorescence transition is allowed and long-axis polarized.
    No preview · Article · Feb 1971 · The Journal of Physical Chemistry
  • Isadore B. Berlman
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    ABSTRACT: From experimental evidence it is inferred that the broad structureless absorption band of biphenyl at about 2500 Å is composed of bands from three transitions, a weak transition similar to the 1A ↠ 1Lb transition of benzene and two stronger transitions similar to the 1A ↠ 1La and 1A ↠ 1B transitions of benzene. Bands from these transitions are separated in rigid biphenyl analogs such as 9,10-dihydrophenanthrene and fluorene. Certain fluorescence characteristics of biphenyl (such as decay time Τ and quantum yield Q) are distinctive of the weak and “hidden” transition and a dramatic change in these characteristics is observed when a crossover of the two lowest excited states is achieved in the analogs of biphenyl. Specific substituents, when positioned in the para position (such as a phenyl or vinyl group in p-terphenyl or 4-vinylbiphenyl, respectively), are particularly efficacious in producing a crossover of levels. In these cases, the lowest excited state is an allowed transition similar to one component of the degenerate 1A ↠ 1B transition in benzene. Since the intense absorption bands are maximally shifted by substituents on the para position, the transition moment must be long-axis polarized as predicted theoretically. Bridging is particularly effective in producing a bathochromic shift because the phenyl rings can be constrained to lie in a relatively coplanar and linear configuration. The magnitude of the shift imparted to the various states depends on the bridging element. From the value of the ratio Τ ∕ Q, the assignment of the lowest excited singlet state can be determined: In fluorene, dibenzofuran, and 9,10-dihydrophenanthrene, it is 1La; in carbazole and phenanthrene, 1Lb; and in 2-phenylfluorene and 2-phenyl-9,2′-methylenefluorene, 1Bb.
    No preview · Article · Jun 1970 · The Journal of Chemical Physics
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    I. B. Berlman
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    ABSTRACT: Certain of the presently known aromatic molecules, for example, p-terphenyl and PBD, have relatively fast fluorescence rise and decay times. However, to keep pace with recent developments in fast electronic circuitry and in photomultiplier tubes, scintillators are needed with even faster decay times. Some factors relevant to a short lifetime will be discussed—mainly from an empirical viewpoint.
    Preview · Article · Jun 1968
  • I. B. Berlman · O. J. Steingraber · M. J. Benson
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    ABSTRACT: Many hydrogen‐filled lamps have been tested and the effect of each of several parameters on the intensity and shape of the radiation pulse determined. The parameters were gas pressure, type of gas (hydrogen or deuterium), tube voltage, and electrode gap distance. A flash lamp has been designed and built which is simple, inexpensive, and easily disassembled. Our results show that deuterium‐filled tubes with 2 mm gaps emit about (65±10)% more photons per discharge than hydrogen‐filled tubes operated under similar conditions. The parameters favorable for a high intensity discharge are large gap with deuterium gas—for a rapid discharge, high pressure and voltage.
    No preview · Article · Feb 1968 · Review of Scientific Instruments
  • Isadore B. Berlman · Hermann O. Wirth · O. J. Steingraber
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    ABSTRACT: The fluorescence characteristics of fluoranthene and three of its derivatives, 3-phenylfluoranthene, 3,3′-bifluoranthenyl, and 3-aminofluoranthene, are reported. For fluoranthene in particular, the natural lifetime, Stokes shift, and relative immunity to concentration and oxygen quenching are found to be anomalous. The first two of these characteristics, long lifetime and large Stokes shift, are interpreted as supporting evidence that fluorescence takes place from a partially hidden level. For the most intense absorption band associated with this transition (1Lb), εmax is estimated to be 270 ± 40. The anomalous immunity to quenching has not been explained as yet. Depending on the type and position of the substituents, derivatives of fluoranthene also possess some or all of the above anomalies. The synthesis and purification of the above derivatives of fluoranthene are also reported.
    No preview · Article · Jan 1968 · Journal of the American Chemical Society
  • I. B. Berlman · O. J. Steingraber
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    ABSTRACT: Scitation is the online home of leading journals and conference proceedings from AIP Publishing and AIP Member Societies
    No preview · Article · Sep 1965 · The Journal of Chemical Physics
  • O. J. Steingraber · I. B. Berlman
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    ABSTRACT: A new method of accurately recording scintillation pulse contours over several decades is described. Scintillation pulses are analyzed by an apparatus which combines the very fast rise time of a pulse sampling oscilloscope and the digital storage capacity of a multichannel analyzer. A special feature of this technique is its ability to accept, within limits, pulses random in time and amplitude so that fluorescence from samples excited either by pulsed uv radiation, β, or α particles may be analyzed. This apparatus, in combination with a hydrogen flash tube and a monochromator, has been used to measure the decay time of fluorescent solutions as a function of the wavelength of the exciting radiation. Decay time measurements have also been made for various modes of excitation: α particle, β particle, and pulsed uv.
    No preview · Article · Jun 1963 · Review of Scientific Instruments
  • I. B. Berlman · R. Grismore · B. G. Oltman
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    ABSTRACT: The ratio of alpha -stimulated to BETA -stimulated luminescence, the ; alpha / BETA ratio, was studied in binary and ternary organic scintillation ; solutions. The ratio was found to vary with the decay time of the solvent and/or ; the solute. To explain the low fluorescence yield under alpha -particle ; excitation, transient free radicals produced along the alpha track are assumed ; to contribute to the dynamic quenching parameter. (auth);
    No preview · Article · Jan 1963 · Transactions of the Faraday Society
  • I. B. Berlman · T. A. Walter
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    ABSTRACT: The effects of deuterium labeling on the formation of the Diels-alder ; adduct from maleic anhydride and 2-methylfuran were studied. Labeled adducts II ; and III were prepared using maleic anthydride-dâ and 2-methylfuran-5-d, ; respectively. The rates of decomposition of II, III, and unlabeled adduct (I) ; were measured at 50 deg C in isooctane solution. The data were used to derive ; first-order rate constants for the formation of the adducts; the isotope effects ; were found to be k/sub I// k/sub II/ = 1.15 plus or minus 0.01 and k/sup I//K/; sub III/ = 1 .07 plus or minus 0.01, indicating that the rate-determining ; reaction involves only one Step. (D.L.C.);
    No preview · Article · Oct 1962 · The Journal of Chemical Physics
  • Isadore B. Berlman · Arye Weinreb
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    ABSTRACT: The effect of temperature, solvent, concentration of solute and quenching by oxygen on the decay time and fluorescence spectrum of naphthalene was investigated. At high solute concentrations (>0·1 M) an anomaly in the emission spectrum is interpreted as being due to transient dimers, whereas at lower solute concentrations (
    No preview · Article · Jul 1962 · Molecular Physics
  • W. R. Anderson · I. B. Berlman
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    ABSTRACT: Of the total radiant flux produced in a right-circular cylindrical cell ; containing a uniformly distributed isotropic source of radiant energy, the ; fraction emanating from the end window is computed both for a cell with ideal, ; perfectly reflecting mirror surfaces and for a cell with ideal, totally absorbing ; surfaces. Graphs are presented of the calculated radiant-flux fractions from the ; cylinder as a function of the absorbance of the contents. Also presented are ; results of measurements of the radiant flux emitted from a cylindrical cell ; containing an externally excited scintillating solution when the inner reflecting ; surfaces of the cell are polished aluminum, aluminum evaporated on glass, ; aluminum oxide, and Teflon. These results are expressed relative to the radiant ; flux emitted by the same cell-solution combination with blackened inner cell ; surfaces. The actual radiant-flux fractions emitted by the cells are estimated ; by using the calculation for a cell possessing ideal, totally absorbing surfaces. ; (auth);
    No preview · Article · Nov 1961 · Journal of the Optical Society of America
  • Isadore B. Berlman
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    ABSTRACT: Scitation is the online home of leading journals and conference proceedings from AIP Publishing and AIP Member Societies
    No preview · Article · Mar 1961 · The Journal of Chemical Physics
  • Isadore B. Berlman
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    ABSTRACT: The relative intensity of the light pulses produced by α and β particles in a scintillating solution of 2,5-diphenyloxazole (PPO) in xylene has been investigated as a function of the concentration of the solute. The α/β ratio is substantially smaller than that found in organic plastic scintillators. From the data the dynamic quenching parameter has been calculated. Several independent experiments, i.e., measurements pertaining to mean lifetime of fluorescence, uv excitation, and pulse heights, were undertaken to study the mechanisms of quenching by oxygen in a scintillating solution. The best interpretation of the oxygen effect is consistent with the existence of dynamic quenching of the solvent and of the solute.
    No preview · Article · Feb 1961 · The Journal of Chemical Physics
  • I. B. Berlman · R. Grismore · B. G. Oltman
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    ABSTRACT: Improvements are presented in the use of the ``twin'' scintillation detector described in an earlier paper. Conditions are specified under which the fluorescence yield is maximized and the proton to electron ratio equalized in both solutions. For a neutron energy of 2.19 Mev the instrumental line width is 23%. The estimated lower limit of its potential range is ¼ to ⅓ mev. Other improvements in sensitivity have permitted the measurement of background neutron fluxes of the order of those produced by cosmic rays.
    No preview · Article · Dec 1960 · Review of Scientific Instruments
  • Isadore B. Berlman
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    ABSTRACT: The nonradiative energy transfer of an organic scintillating solution (diphenyloxazole in p-xylene) as a function of the solute concentration was determined by three independent methods: direct measurements of the fluorescent lifetime, the light output of the solvent, and the light output of the solute. The efficiency of energy transfer ranges from 12% at 0.02 g/l to 92% at 2 g/l of PPO in xylene. The results from the three methcds agree within a few per cent. (auth)
    No preview · Article · Oct 1960 · The Journal of Chemical Physics
  • I. B. Berlman · R. Grismore · B. G. Oltman
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    ABSTRACT: The effect of dynamic quenching in organic scintillation liquids on the ; value of the alpha / BETA ratio is shown to be influenced by the decay time of ; the solvent and/or the solute. In ternary systems containing cyclohexane and ; benzene in various proportions as the solvents and diphenyloxazole (PPO) as the ; solute the effect of the decay time of the solvent on the alpha / BETA ratio is ; demonstrated by a luminescence minmum. Also, the alpha / BETA ratio is shown ; to vary as the decay time of the solute in four binary solutions with benzene as ; the common solvent. The assumption is made that the magnitude of the dynamic ; quenching in a binary solution should be influenced by the radiation ; susceptibility of the solvent to the formation of transient free radicals (G/sub ; r/). In eleven solutions with PPO as the common solute the alpha / BETA ratio ; appears to vary inversely as G/sub r/ of the solvent. (auth);
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  • I. B. Berlman · O. J. Steingraber

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  • W. R. Anderson · I. B. Berlman
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    ABSTRACT: Gamma radiation effects on the luminescence efficiency of scirtillating ; solutions of 2,5-diphenyoxazole (PPO) in p-xylene are measured. The irradiations ; of the xylene are carried out prior to the addition of the PPO. The decrease in ; luminescence efficiency is found to be largely or entirely accounted for by the ; decrease in transparency of the solution upon irradiation and by the quenching of ; the excited solvert and scintillator molecules by radiation-produced molecules. ; (T. F.H.);
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