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Description: Tests on 1-gpm and 0.5-gpm hydroclones showed them to be unnecessary. Solvent-aqueous phase separation, although effective when optimized, was infrequently required. The 1-gpm hydroclone produced better water separation than the 0.5-gpm hydroclone for similar control parameters. Decontamination factors for widely varying flow conditions ranged from 1 to 3. Introduction of water into the hydroclone feed stream had no effect on decontamination or particle removal. (auth)
Date: March 31, 1958
Creator: Cerny, J. III
Partner: UNT Libraries Government Documents Department

Current and future directions in the study of light nuclei employing an on-line mass separator

Description: Recent work on isospin quintets utilizing the on-line mass analysis system RAMA is described. Possibilities for future studies of both proton-rich and neutron-rich light nuclides towards the limits of nuclear stability are discussed. 4 figures.
Date: September 1, 1979
Creator: Aeystoe, J. & Cerny, J.
Partner: UNT Libraries Government Documents Department


Description: The four-nucleon transfer reaction {sup 12}C({sup 10}B, {sup 6}Li*(2.18 MeV)) {sup 16}O has been studied at 68 MeV by coincidence measurement of the d + {alpha} breakup particles. The reaction is quite selective as is observed in other established {alpha}-transfer reactions.
Date: July 1, 1980
Creator: Bice, A.N.; Shotter, A.C.; Stahel, D.P. & Cerny, J.
Partner: UNT Libraries Government Documents Department

Trends in the study of light proton rich nuclei

Description: Recent work in light proton-rich nuclei is reviewed. Evidence for the first T/sub z/ = -5/2 nuclide, /sup 35/Ca, is presented. The mechanisms of two-proton emission following beta-decay is investigated. Future directions in this field are discussed. 23 refs., 5 figs. (WRF)
Date: September 1, 1985
Creator: Moltz, D.M.; Aysto, J.; Hotchkis, M.A.C. & Cerny, J.
Partner: UNT Libraries Government Documents Department

Beta-delayed two-proton emission as a nuclear probe

Description: A brief history of beta-delayed two-proton emission is given. Speculations about future experiments which would enhance our knowledge about both nuclear spectroscopy and this relatively unique decay mode are presented. 16 refs., 7 figs.
Date: September 1, 1987
Creator: Moltz, D.M.; Reiff, J.E.; Robertson, J.D.; Lang, T.F. & Cerny, J.
Partner: UNT Libraries Government Documents Department

Discovery of beta-delayed two-proton radioactivity in /sup 22/Al and /sup 26/P

Description: /sup 22/Al(tau/sub 1/1/ approx. 70 ms) and /sup 26/P(tau/sub 1/2/ approx. 20 ms) were produced via the (/sup 3/He,p4n) reaction on /sup 24/Mg and /sup 28/Si targets, respectively, using 110 MeV /sup 3/He/sup +2/ beams of 3 to 7 ..mu..A from the 88-inch Cyclotron at the Lawrence Berkeley Laboratory: the effective cross section for their observation as high energy (7 to 8 MeV), beta-delayed single proton emitters was approx. a few nb. A helium jet system and a high geometry, three-element particle telescope (..delta..E1,..delta..E2,E) were used to search for two-proton decay events. Symmetrically divided, circular ..delta..E1 (24 ..mu..m for /sup 22/Al, 14 ..mu..m for /sup 26/P0 and ..delta..E2 (155 to 170 ..mu..m) detectors were employed to observe coincident, low-energy protons with each telescope subtending 4.5% of 4..pi.. sr. A standard 500 ..mu..m E detector placed behind and in coincidence with either of these two-counter telescopes observed the high energy groups from beta-delayed single proton decay as a monitor of the reactions. Results are presented. (WHK)
Date: January 1, 1983
Creator: Cable,M.D.; Honkanen, J.; Parry, R.F.; Zhou, S.H.; Zhou, Z.Y. & Cerny, J.
Partner: UNT Libraries Government Documents Department

DECAYS OF THE Tz = -2 NUCLEI 20Mg, 24Si AND 36Ca

Description: Beta-delayed protons have been observed from the decays of the mass separated T{sub z} = -2 nuclides {sup 20}Mg, {sup 24}Si, and {sup 36}Ca. From these proton spectra the mass excesses of the lowest T = 2 states in the T{sub z} = -1 nuclei {sup 20}Na, {sup 24}Al, and {sup 36}K are determined to be 13420 {+-} 50 keV ({sup 20}Na), 5903 {+-} 9 keV ({sup 24}Al), and - 13168 {+-} 22 keV ({sup 36}K). The complete A = 20, 24, and 36 isospin quintets have all their members bound against isospin allowed particle-decay modes, providing a stringent test of the isobaric multiplet mass equation. Good agreement is observed for all these quintets using only the quadratic form of this equation. Radioactivity {sup 20}Mg, {sup 24}Si, {sup 36}Ca (mass separated); measured {beta}-delayed protons; deduced T{sub 1/2} and proton branching; derived mass excesses of the lowest 0{sup +}, T = 2 states in {sup 20}Na, {sup 24}Al, and {sup 36}K; deduced coefficients of the isobaric multiplet mass equation.
Date: June 1, 1980
Creator: Aysto, J.; Cable, M.D.; Parry, R.F.; Wouters, J.M.; Moltz, D.M. & Cerny, J.
Partner: UNT Libraries Government Documents Department

Additional results from the beta-delayed proton decays of {sup 27}P and {sup 31}Cl

Description: The experimental investigation of the decays of proton-rich light nuclei has provided a wealth of spectroscopic information. This includes details of energy levels, spins, isospins, masses, half-lives and other decay properties. In light nuclei, total beta decay energies rapidly increase as one moves away from the valley of beta-stable nuclides towards the proton drip line. This opens up decay modes, such as beta-delayed proton and beta-delayed alpha emission, which are very sensitive probes of nuclear structure. There have been several recent articles that review the decay properties of proton drip-line nuclei. The beta decays of proton-rich light nuclei (with T{sub z} {le} -1/2) are characterized by two general features. The first is a fast superallowed Fermi transition to the isobaric analog state (IAS) in the beta daughter. If the IAS is above the proton separation energy, the beta-decaying precursor nuclide is classified as a strong beta-delayed proton emitter. The A = 4n+1, T{sub z}=-3/2 series of nuclei from {sup 17}Ne to {sup 73}Sr (with the exception of the unobserved member {sup 69}Kr), are all strong {Beta}p emitters. In contrast, the A = 4n, T{sub z}=-1 series of nuclei, from {sup 24}Al to {sup 48}Mn are designated as weak {Beta}p emitters since the IAS in the beta daughters is bound with respect to proton emission.
Date: May 1, 1996
Creator: Ognibene, T.J.; Powell, J.; Moltz, D.M.; Rowe, M.W. & Cerny, J.
Partner: UNT Libraries Government Documents Department

Advances in the helium-jet coupled on-line mass separator RAMA. [Recoil Atom Mass Analyzer]

Description: General improvements to the on-line mass separator RAMA (Recoil Atom Mass Analyzer) have yielded a greater reliability and efficiency for some elements. A new utilitarian helium-jet chamber has been installed to facilitate quick target and degrader foil changes in addition to a new ion source holder. A higher efficiency hollow-cathode, cathode-extraction ion source, for lower melting point elements (< 1200/sup 0/C) has also been designed. Tests with the beta-delayed proton emitter /sup 37/Ca showed a factor of five increase in yield over the old hollow-cathode, anode-extraction source. A differentially-pumped-tape drive system compatible with both ..gamma..-..gamma.. and ..beta..-..gamma.. experiments has been incorporated into the general detection system. All major operating parameters will soon be monitored by a complete stand-alone microprocessor system which will eventually be upgraded to a closed-loop control system.
Date: January 1, 1980
Creator: Moltz, D M; Aysto, J; Cable, M D; Parry, R F; Haustein, P E; Wouters, J M et al.
Partner: UNT Libraries Government Documents Department

Delayed proton activities produced in /sup 24/Mg + Ca and /sup 28/Si + Ca reactions

Description: A search for new delayed proton emitters in /sup 24/Mg and /sup 28/Si bombardments of Ca targets has been conducted to extend knowledge about the proton drip line in the A = 60 to 65 mass region. Definitive evidence for the A = 4n + 1, T/sub z/ = -3/2 nuclide /sup 61/Ge is presented, but a search for the next member in this series, /sup 65/Se, proved fruitless. 6 refs., 3 figs.
Date: June 1, 1986
Creator: Hotchkis, M.A.C.; Moltz, D.M.; Reiff, J.E.; Blonnigen, F.; Lang, T.F.; Xu, X. et al.
Partner: UNT Libraries Government Documents Department

The other high resolution post accelerator approach

Description: There has been significant discussion in consideration of a high resolution mass separator followed by a RFQ and a linear accelerator as the basic format for IsoSpin Laboratory. There exists another strong possibility-namely a low-resolution mass separator coupled to a cyclotron. The major objection to this approach has been that the conversion from the +1 mass separator beam to a q/m beam of 1/4 to 1/3 is thought to be highly inefficient. Since we are in the fortunate position of having the two expensive components of this system available for tests (an on-line mass separator and an ECR source), we intend to couple these devices to actually measure these efficiencies and to test ideas for improving the efficiency. We present some specifics of this approach.
Date: May 24, 1993
Creator: Moltz, D. M.; Tighe, R. J.; Rowe, M. W.; Ognibene, T. J. & Cerny, J.
Partner: UNT Libraries Government Documents Department

Characterization of a Tunable Quasi-Monoenergetic Neutron Beamfrom Deuteron Breakup

Description: A neutron irradiation facility is being developed at the88-Inch Cyclotron at Lawrence Berkeley National Laboratory for thepurposes of measuring neutron reaction cross sections on radioactivetargets and for radiation effects testing. Applications are of benefit tostockpile stewardship, nuclear astrophysics, next generation advancedfuel reactors, and cosmic radiation biology and electronics in space. Thefacility will supply a tunable, quasi-monoenergetic neutron beam in therange of 10-30 MeV or a white neutron source, produced by deuteronbreakup reactions on thin and thick targets, respectively. Because thedeuteron breakup reaction has not been well studied at intermediateincident deuteron energies, above the target Coulomb barrier and below 56MeV, a detailed characterization was necessary of the neutron spectraproduced by thin targets.Neutron time of flight (TOF) methods have beenused to measure the neutron spectra produced on thin targets of low-Z(titanium) and high-Z (tantalum) materials at incident deuteron energiesof 20 MeV and 29 MeV at 0 deg. Breakup neutrons at both energies fromlow-Z targets appear to peak at roughly half of the available kineticenergy, while neutrons from high-Z interactions peak somewhat lower inenergy, owing to the increased proton energy due to breakup within theCoulomb field. Furthermore, neutron spectra appear narrower for high-Ztargets. These centroids are consistent with recent preliminary protonenergy measurements using silicon telescope detectors conducted at LBNL,though there is a notable discrepancy with spectral widths.
Date: December 14, 2006
Creator: Bleuel, D.L.; McMahan, M.A.; Ahle, L.; Barquest, B.R.; Cerny, J.; Heilbronn, L.H. et al.
Partner: UNT Libraries Government Documents Department

Neutron Beams from Deuteron Breakup at the 88-Inch Cyclotron at Lawrence Berkeley National Laboratory

Description: Accelerator-based neutron sources offer many advantages, in particular tunability of the neutron beam in energy and width to match the needs of the application. Using a recently constructed neutron beam line at the 88-Inch Cyclotron at LBNL, tunable high-intensity sources of quasi-monoenergetic and broad spectrum neutrons from deuteron breakup are under development for a variety of applications.
Date: July 31, 2007
Creator: McMahan, M.A.; Ahle, L.; Bleuel, D.L.; Bernstein, L.; Braquest, B.R.; Cerny, J. et al.
Partner: UNT Libraries Government Documents Department

Reinvestigation of the Direct Two-proton Decay of the Long-lived Isomer 94Agm [0.4 s, 6.7 MeV, (21+)]

Description: An attempt to confirm the reported direct one-proton and two-proton decays of the (21+) isomer at 6.7(5) MeV in 94Ag has been made. The 0.39(4) s half-life of the isomer permitted use of a helium-jet system to transport reaction products from the 40Ca + natNi reaction at 197 MeV to a low-background area; 24 gas Delta E-(Si) E detector telescopes were used to identify emitted protons down to 0.4 MeV. No evidence was obtained for two-proton radioactivity with a summed energy of 1.9(1) MeV and a branching ratio of 0.5(3)percent. Two groups of one-proton radioactivity from this isomer had also been reported; our data confirm the lower energy group at 0.79(3) MeV with its branching ratio of 1.9(5)percent.
Date: March 5, 2009
Creator: Cerny, J.; Moltz, D. M.; Lee, D. W.; Perajarvi, K.; Barquest, B. R.; Grossman, L. E. et al.
Partner: UNT Libraries Government Documents Department

Improvements to the helium-jet coupled on-line mass separator RAMA

Description: Some general improvements to the on-line mass separator RAMA have yielded a factor of five increase in yield for most elements. By placing the ion source region at the full accelerating potential of 20 kV, the effective skimmer-plasma distance has been reduced from 12 cm to <2 cm. Changes in the helium-jet chamber and large volume pumping arrangement necessitated by placing the ion source region at high voltage are also given. Finally, details for a new highly shielded detector station are presented.
Date: August 1, 1986
Creator: Bloennigen, F.B.; Moltz, D.M.; Lang, T.F.; Knoll, W.F.; Xu, X.; Hotchkis, M.A.C. et al.
Partner: UNT Libraries Government Documents Department

Studies of isospin quintets and neutron-deficient indium isotopes with the on-line mass analysis system RAMA

Description: The success of the isobaric multiplet mass equation in relating mass excesses of members of light isospin quarters has permitted it to pay a significant role in predicting ground state masses of highly proton-rich 1f2p shell nuclides. An overview is given of an experimental program that was developed to study the most proton-rich members of high-isospin multiplets through radioactive decay. An instrument known as RAMA, for Recoil Atom Mass Analyzer, was constructed and is briefly described. Experiments to determine total decay energies of isotopes in the vicinity of the doubly-magic nucleus /sup 100/Sn were begun. Preliminary results on the total decay energies and mass excesses of /sup 103/In and /sup 105/In are given. 6 figures, 2 tables. (RWR)
Date: September 1, 1979
Creator: Cerny, J.; Aysto, J.; Cable, M.D.; Haustein, P.E.; Moltz, D.M.; von Dincklage, R.D. et al.
Partner: UNT Libraries Government Documents Department


Description: We have for some time been interested in developing a reasonably fast and universal (having little or no chemical selectivity) on-line mass analysis system to expand our capabilities in studying nuclei far from stability. The system selected was originally proposed by Nitschke and is termed RAMA an acronym for Recoil Atom Mass Analyzer. Basically, this system utilizes the helium-jet method to transport activity to a Sidenius hollow-cathode ion source which is coupled to a mass spectrometer. A comprehensive discussion of RAMA will appear elsewhere.
Date: November 1, 1977
Creator: Cerny, J.; Moltz, D.M.; Evans, H.C.; Vieira, D.J.; Parry, R.F.; Wouters, J.M. et al.
Partner: UNT Libraries Government Documents Department

Recent Studies of Proton Drip-Line Nuclei Using the Berkeley Gas-Filled Separator

Description: The Berkeley Gas-filled Separator provides new research opportunities at Lawrence Berkeley National Laboratory's X-Inch Cyclotron. The use of this apparatus for the study of proton drip-line nuclides is discussed. Preliminary results of {sup 78}Kr bombardments of {sup 102}Pd targets at mid-target energies of 360, 375 and 385 MeV are presented. Improvements planned partially as a result of this measurement are also discussed.
Date: October 7, 1999
Creator: Rowe, M.W.; Batchelder, J.C.; Ninov, V.; Gregorich, K.E.; Toth, K.S.; Bingham, C.R. et al.
Partner: UNT Libraries Government Documents Department

First in-beam. gamma. -ray study of sup 67 As

Description: Excited states of the neutron-deficient nucleus {sup 67}As were populated using the {sup 40}Ca({sup 32}S,{alpha}p){sup 67}As and the {sup 40}Ca({sup 33}S,{alpha}pn){sup 67}As reactions at bombarding energies between 95 and 110 MeV. We present a tentative level scheme for {sup 67}As, derived from {gamma}-{gamma} coincidence studies in conjunction with measurement of evaporated charged particles and neutrons.
Date: January 1, 1990
Creator: Lang, T.F.; Moltz, D.M.; Reiff, J.E.; Batchelder, J.C.; Ognibene, T.J.; Cerny, J. et al.
Partner: UNT Libraries Government Documents Department

Preliminary Ionization Efficiencies of {sup 11}C and {sup 14}O with the LBNL ECR Ion Sources

Description: High charge states, up to fully stripped {sup 11}C and {sup 14}O ion, beams have been produced with the electron cyclotron resonance ion sources (LBNL, ECR and AECR-U) at Lawrence Berkeley National Laboratory. The radioactive atoms of {sup 11}C and {sup 14}O were collected in batch mode with an LN{sub 2} trap and then bled into the ECR ion sources. Ionization efficiency as high as 11% for {sup 11}C{sup 4+} was achieved.
Date: October 5, 1998
Creator: Xie, Z.Q.; Cerny, J.; Guo, F.Q.; Joosten, R.; Larimer, R.M.; Lyneis, C.M. et al.
Partner: UNT Libraries Government Documents Department

Production of beams of neutron-rich nuclei between Ca and Ni using the ion-guide technique

Description: Since several elements between Z = 20-28 are refractory in their nature, their neutron-rich isotopes are rarely available as low energy Radioactive Ion Beams (RIB) in ordinary Isotope Separator On-Line facilities [1-4]. These low energy RIBs would be especially interesting to have available under conditions which allow high-resolution beta-decay spectroscopy, ion-trapping and laser-spectroscopy. As an example, availability of these beams would open a way for research which could produce interesting and important data on neutron-rich nuclei around the doubly magic {sup 78}Ni. One way to overcome the intrinsic difficulty of producing these beams is to rely on the chemically unselective Ion Guide Isotope Separator On-Line (IGISOL) technique [5]. Quasi- and deep-inelastic reactions, such as {sup 197}Au({sup 65}Cu,X)Y, could be used to produce these nuclei in existing IGISOL facilities, but before they can be successfully incorporated into the IGISOL concept their kinematics must be well understood. Therefore the reaction kinematics part of this study was first performed at the Lawrence Berkeley National Laboratory using its 88'' cyclotron and, based on those results, a specialized target chamber was built[6]. The target chamber shown in Fig. 1 was recently tested on-line at the Jyvaaskylaa IGISOL facility. Yields of mass-separated radioactive projectile-like species such as {sup 62,63}Co are about 0.8 ions/s/pnA, corresponding to about 0.06 % of the total IGISOL efficiency for the products that hit the Ni-degrader. (The current maximum 443 MeV {sup 65}Cu beam intensity at Jyvaaskylaa is about 20 pnA.) This total IGISOL efficiency is a product of two coupled loss factors, namely inadequate thermalization and the intrinsic IGISOL efficiency. In our now tested chamber, about 9 % of the Co recoils are thermalized in the owing He gas (p{sub He}=300 mbar) and about 0.7 % of them are converted into the mass-separated ion beams. In the future, both of these ...
Date: September 28, 2004
Creator: Perajarvi, K.; Cerny, J.; Hager, U.; Hakala, J.; Huikari, J.; Jokinen, A. et al.
Partner: UNT Libraries Government Documents Department