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U. Datta Pramanik,
T. Aumann,
K. Boretzky,
D. Cortina,
Th. W. Elze,
H. Emling,
H. Geissel,
M. Hellström,
K. L. Jones,
L. H. Khiem, [......],
Y. Leifels,
G. Münzenberg,
C. Nociforo,
R. Palit,
H. Scheit,
H. Simon,
K. Sümmerer,
S. Typel,
W. Walus,
H. Weick
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D. M. Rossi,
P. Adrich,
F. Aksouh,
H. Alvarez-Pol,
T. Aumann,
J. Benlliure,
M. Böhmer,
K. Boretzky,
E. Casarejos,
M. Chartier, [......],
R. Palit,
S. Paschalis,
R. Plag,
R. Reifarth,
H. Simon,
K. Sümmerer,
A. Wagner,
W. Walus,
H. Weick,
M. Winkler
[show abstract]
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ABSTRACT: Exotic Ni isotopes have been measured at the R3B-LAND setup at GSI in
Darmstadt, using Coulomb excitation in inverse kinematics at beam energies
around 500 MeV/u. As the experimental setup allows kinematically complete
measurements, the excitation energy was reconstructed using the invariant mass
method. The GDR and additional low-lying strength have been observed in 68Ni,
the latter exhausting 4.1(1.9)% of the E1 energy-weighted sum rule. Also, the
branching ratio for the non-statistical decay of the excited 68Ni nuclei was
measured and amounts to 24(4)%.
09/2012;
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ABSTRACT: Boron determination in blood and tissue samples is a crucial task especially for treatment planning, preclinical research, and clinical application of boron neutron capture therapy (BNCT). Comparison of clinical findings remains difficult due to a variety of analytical methods, protocols, and standard reference materials in use. This paper addresses the comparability of inductively coupled plasma mass spectrometry, quantitative neutron capture radiography, and prompt gamma activation analysis for the determination of boron in biological samples. It was possible to demonstrate that three different methods relying on three different principles of sample preparation and boron detection can be validated against each other and yield consistent results for both blood and tissue samples. The samples were obtained during a clinical study for the application of BNCT for liver malignancies and therefore represent a realistic situation for boron analysis.
Analytical and Bioanalytical Chemistry 08/2012; 404(6-7):1887-95. · 3.78 Impact Factor
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S Hofmann,
S Heinz,
R Mann,
J Maurer,
J Khuyagbaatar,
D Ackermann,
S Antalic,
W Barth,
M Block,
H G Burkhard, [......],
J Runke,
S Saro,
D A Shaughnessy,
M A Stoyer,
P Thoerle-Pospiech,
K Tinschert,
N Trautmann,
J Uusitalo,
P A Wilk,
A V Yeremin
European Physical Journal A 05/2012; 48(5). · 2.19 Impact Factor
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U Datta Pramanik,
T Aumann,
D Cortina,
H Emling,
H Geissel,
M Hellström,
R Holzmann,
N Iwasa,
Y Leifels,
G Münzenberg, [......],
A Grünschloss,
S Ilievski,
K Boretzky, J V Kratz,
R Kulessa,
E Lubkiewicz,
E Wajda,
W Walus,
P Reiter,
H Simon
[show abstract]
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ABSTRACT: Coulomb breakup of neutron-rich nuclei around mass A ∼ 20 has been studied experimentally using secondary beams (∼ 500–600 MeV/u) of unstable nuclei produced at GSI. The spectroscopic
factor deduced for the neutron occupying s
1/2 level in 15C ground state is consistent with the earlier reported value. The data analysis for Coulomb breakup of 17C shows that most of the cross section yields the 16C core in its excited state. For 17–22O, the low-lying E1 strength amounts up to about 12% of the energy weighted dipole sum rule strength depending on neutron
excess. The cluster sum rule limit with 16O as a core is almost exhausted for 17,18O, while for more neutron rich isotopes the strength with respect to that limit decreases.
Pramana 04/2012; 57(2):535-544. · 0.57 Impact Factor
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I. Altarev,
M. Daum,
A. Frei,
E. Gutsmiedl,
G. Hampel,
F. J. Hartmann,
W. Heil,
A. Knecht, J. V. Kratz,
T. Lauer,
M. Meier,
S. Paul,
U. Schmidt,
Y. Sobolev,
N. Wiehl,
G. Zsigmond
[show abstract]
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ABSTRACT: We have determined for the first time the velocity distribution of neutrons from a solid 2H2 ultracold neutron (UCN) source. The spectrum rises sharply above 4.5m/s and has a maximum around 7m/s after transport in
an 8m long guide. The number of neutrons in the UCN velocity range (< 7m/s) may be increased by a factor of two by placing
the experiment 1m above the UCN source level.
European Physical Journal A 04/2012; 37(1):9-14. · 2.19 Impact Factor
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U Forsberg,
P Golubev,
L G Sarmiento,
J Jeppsson,
D Rudolph,
L -L Andersson,
D Ackermann,
M Asai,
M Block,
K Eberhardt, [......],
S Lahiri,
B Lommel,
M Maiti,
E Merchan,
J P Omtvedt,
E Parr,
J Runke,
H Schaffner,
M Schaedel,
A Yakushev
[show abstract]
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ABSTRACT: To identify the atomic number of superheavy nuclei produced in Ca-48-induced fusion-evaporation reactions, an experiment aiming at measuring characteristic X-rays is being prepared at GSI, Darmstadt, Germany. The gas-filled separator TASCA will be employed, sending the residues towards the multi-coincidence detector setup TASISpec. Two ion-optical modes relying on differing magnetic polarities of the quadrupole magnets can be used at TASCA. New simulations and experimental tests of transmission and background suppression for these two focusing modes into TASISpec are presented.
Acta Physica Polonica Series B 02/2012; 43(2):305-311. · 0.90 Impact Factor
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J Khuyagbaatar,
D Ackermann,
L -L Andersson,
J Ballof,
W Bruechle,
Ch. E Duellmann,
J Dvorak,
K Eberhardt,
J Even,
A Gorshkov, [......],
E Merchan,
D Rudolph,
M Schaedel,
H Schaffner,
B Schausten,
E Schimpf,
A Semchenkov,
A Serov,
A Tuerler,
A Yakushev
[show abstract]
[hide abstract]
ABSTRACT: The average charge states of Pb-188 and No-252,No-254 ions in dilute helium gas were measured at the gas-filled recoil separator TASCA. Hydrogen gas was also used as a filling gas for measurements of the average charge state of No-254. Helium and hydrogen gases at pressures from 0.2 mbar to 2.0 mbar were used. A strong dependence of the average charge state on the pressure of the filling gases was observed for both, helium and hydrogen. The influence of this dependence, classically attributed to the so-called "density effect", on the performance of TASCA was investigated. The average charge states of No-254 ions were also measured in mixtures of helium and hydrogen gases at low gas pressures around 1.0 mbar. From the experimental results simple expressions for the prediction of average charge states of heavy ions moving in rarefied helium gas, hydrogen gas, and in their mixture were derived. (C) 2012 Elsevier B.V. All rights reserved.
Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment 01/2012; 689:40-46. · 1.21 Impact Factor
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[show abstract]
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ABSTRACT: Nuclear Security aims at the prevention and detection of and response to, theft, sabotage, unauthorized access, illegal transfer or other malicious acts involving nuclear material. Nuclear Forensics is a key element of nuclear security. Nuclear Forensics is defined as a methodology that aims at re-establishing the history of nuclear material of unknown origin. It is based on indicators that arise from known relationships between material characteristics and process history. Thus, nuclear forensics analysis includes the characterization of the material and correlation with production history. To this end, we can make use of parameters such as the isotopic composition of the nuclear material and accompanying elements, chemical impurities, macroscopic appearance and microstructure of the material. In the present paper, we discuss the opportunities for attribution of nuclear material offered by nuclear forensics as well as its limitations. Particular attention will be given to the role of nuclear reactions. Such reactions include the radioactive decay of the nuclear material, but also reactions with neutrons. When uranium (of natural composition) is exposed to neutrons, plutonium is formed, as well as 236U. We will illustrate the methodology using the example of a piece of uranium metal that dates back to the German nuclear program in the 1940's. A combination of different analytical techniques and model calculations enables a nuclear forensics interpretation, thus correlating the material characteristics with the production history.
Journal of Physics Conference Series 09/2011; 312(6):062003.
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ABSTRACT: This study investigates the dosimetric feasibility of Boron Neutron Capture Therapy (BNCT) of explanted livers in the thermal column of the research reactor in Mainz. The Monte Carlo code MCNP5 is used to calculate the biologically weighted dose for different ratios of the (10)B-concentration in tumour to normal liver tissue. The simulation results show that dosimetric goals are only partially met. To guarantee effective BNCT treatment the organ has to be better shielded from all gamma radiation.
Applied radiation and isotopes: including data, instrumentation and methods for use in agriculture, industry and medicine 08/2011; 70(1):139-43. · 1.09 Impact Factor
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C Schütz,
C Brochhausen,
S Altieri,
K Bartholomew,
S Bortolussi,
F Enzmann,
D Gabel,
G Hampel,
C J Kirkpatrick, J V Kratz,
S Minouchehr,
H Schmidberger,
G Otto
[show abstract]
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ABSTRACT: The typical primary malignancies of the liver are hepatocellular carcinoma and cholangiocarcinoma, whereas colorectal liver metastases are the most frequently occurring secondary tumors. In many cases, only palliative treatment is possible. Boron neutron capture therapy (BNCT) represents a technique that potentially destroys tumor tissue selectively by use of externally induced, locally confined secondary particle irradiation. In 2001 and 2003, BNCT was applied to two patients with colorectal liver metastases in Pavia, Italy. To scrutinize the rationale of BNCT, a clinical pilot study on patients with colorectal liver metastases was carried out at the University of Mainz. The distribution of the (10)B carrier (p-borono-phenylalanine) in the liver and its uptake in cancerous and tumor-free tissue were determined, focusing on a potential correlation between the uptake of p-borono-phenylalanine and the biological characteristics of cancerous tissue. Samples were analyzed using quantitative neutron capture radiography of cryosections combined with histological analysis. Methodological aspects of the combination of these techniques and results from four patients enrolled in the study are presented that indicate that the uptake of p-borono-phenylalanine strongly depends on the metabolic activity of cells.
Radiation Research 06/2011; 176(3):388-96. · 2.68 Impact Factor
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[show abstract]
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ABSTRACT: Standard wafer solar cells are made of near-semiconductor quality silicon. This high quality material makes up a significant part of the total costs of a solar module. Therefore, new concepts with less expensive so called solar grade silicon directly based on physiochemically upgraded metallurgical grade silicon are investigated. Metallurgical grade silicon contains large amounts of impurities, mainly transition metals like Fe, Cr, Mn, and Co, which degrade the minority carrier lifetime and thus the solar cell efficiency. A major reduction of the transition metal content occurs during the unidirectional crystallization due to the low segregation coefficient between the solid and liquid phase. A further reduction of the impurity level has to be done by gettering procedures applied to the silicon wafers. The efficiency of such cleaning procedures of metallurgical grade silicon is studied by instrumental neutron activation analysis (INAA). Small sized silicon wafers of approximately 200mg with and without gettering step were analyzed. To accelerate the detection of transition metals in a crystallized silicon ingot, experiments of scanning whole vertical silicon columns with a diameter of approximately 1cm by gamma spectroscopy were carried out. It was demonstrated that impurity profiles can be obtained in a comparably short time. Relatively constant transition metal ratios were found throughout an entire silicon ingot. This led to the conclusion that the determination of several metal profiles might be possible by the detection of only one "leading element". As the determination of Mn in silicon can be done quite fast compared to elements like Fe, Cr, and Co, it could be used as a rough marker for the overall metal concentration level. Thus, a fast way to determine impurities in photovoltaic silicon material is demonstrated.
Applied radiation and isotopes: including data, instrumentation and methods for use in agriculture, industry and medicine 05/2011; 69(10):1365-8. · 1.09 Impact Factor
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[show abstract]
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ABSTRACT: As part of the studies on Boron Neutron Capture Therapy at the University of Mainz, Germany, a clinical trial has been started in which, four patients suffering from liver metastases of colorectal carcinoma have been enrolled. Specimens of blood and healthy tissue samples taken from the patients were measured at the PGAA facilities at the HFR in Petten, The Netherlands, and at the FRM II in Munich, Germany. From the measured boron concentrations, pharmacokinetic curves and blood-to-tissue concentration ratios were produced.
Applied radiation and isotopes: including data, instrumentation and methods for use in agriculture, industry and medicine 02/2011; 69(7):936-41. · 1.09 Impact Factor
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J M Gates,
Ch E Duellmann,
M Schaedel,
A Yakushev,
A Tuerler,
K Eberhardt, J V Kratz,
D Ackermann,
L -L Andersson,
M Block, [......],
J Runke,
H Schaffner,
B Schausten,
E Schimpf,
A Semchenkov,
J Steiner,
P Thoerle-Pospiech,
J Uusitalo,
M Wegrzecki,
N Wiehl
[show abstract]
[hide abstract]
ABSTRACT: Experiments with the new recoil separator, Transactinide Separator and Chemistry Apparatus (TASCA), at the GSI were performed by using beams of Ca-48 to irradiate targets of Pb206-208, which led to the production of No252-254 isotopes. These studies allowed for evaluation of the performance of TASCA when coupled to a new detector and electronics system. By following these studies, the isotopes of element 114 ((288-291)114) were produced in irradiations of Pu-244 targets with Ca-48 beams at compound nucleus excitation energies around 41.7 and 37.5 MeV, demonstrating TASCA's ability to perform experiments with picobarn-level cross sections. A total of 15 decay chains were observed and were assigned to the decay of 288-291114. A new a-decay branch in (281)Ds was observed, leading to the new nucleus (277)Hs.
Physical Review C 01/2011; 83(5). · 3.31 Impact Factor
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Ch E Düllmann,
M Schädel,
A Yakushev,
A Türler,
K Eberhardt, J V Kratz,
D Ackermann,
L-L Andersson,
M Block,
W Brüchle, [......],
D Rudolph,
J Runke,
B Schausten,
E Schimpf,
A Semchenkov,
J Steiner,
P Thörle-Pospiech,
J Uusitalo,
M Wegrzecki,
N Wiehl
[show abstract]
[hide abstract]
ABSTRACT: The fusion-evaporation reaction 244Pu(48Ca,3-4n){288,289}114 was studied at the new gas-filled recoil separator TASCA. Thirteen correlated decay chains were observed and assigned to the production and decay of {288,289}114. At a compound nucleus excitation energy of E{*}=39.8-43.9 MeV, the 4n evaporation channel cross section was 9.8{-3.1}{+3.9} pb. At E^{*}=36.1-39.5 MeV, that of the 3n evaporation channel was 8.0{-4.5}{+7.4} pb. In one of the 3n evaporation channel decay chains, a previously unobserved α branch in 281Ds was observed (probability to be of random origin from background: 0.1%). This α decay populated the new nucleus 277Hs, which decayed by spontaneous fission after a lifetime of 4.5 ms.
Physical Review Letters 06/2010; 104(25):252701. · 7.37 Impact Factor
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T Le Bleis,
D Rossi,
A Klimkiewicz,
P Adrich,
K Boretzky,
F Aksouh,
H Alvarez-Pol,
T Aumann,
J Benlliure,
M Boehmer, [......],
R Palit,
S Paschalis,
R Plag,
R Reifarth,
H Simon,
K S̈mmerer,
A Wagner,
W Walus,
H Weick,
M Winkler
[show abstract]
[hide abstract]
ABSTRACT: The appearance of the pygmy-dipole-resonance is a recently observed phenomenon that can be related to neutron-matter properties. Its study can be a tool to determine the nuclear symmetry-energy parameters and thus can contribute constraining neutron star models. We present the (γ,n) cross sections for different Ni isotopes obtained from a measurement in inverse kinematics at about 500 MeV/u in the LAND reaction setup at GSI. The question of the disentanglement of the Coulomb and nuclear contributions is addressed.
Journal of Physics Conference Series 02/2010; 202(1):012035.
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A. Klimkiewicz,
N. Paar,
P. Adrich,
M. Fallot,
T. le Bleis,
D. Rossi,
K. Boretzky,
T. Aumann,
H. Alvarez‐Pol,
F. Aksouh, [......],
R. Plag,
R. Reifarth,
H. Simon,
K. Sümmerer,
G. Surówka,
D. Vretenar,
A. Wagner,
W. Waluś,
H. Weick,
M. Winkler
[show abstract]
[hide abstract]
ABSTRACT: A concentration of dipole strength at energies below the giant dipole resonance was observed in neutron‐rich nuclei around 132Sn in an experiment using the FRS‐LAND setup. This so‐called “pygmy” dipole strength can be related to the parameters of the symmetry energy and to the neutron skin thickness on the grounds of a relativistic quasiparticle random‐phase approximation. Using this ansatz and the experimental findings for 130Sn and 132Sn, we derive a value of the symmetry energy pressure of 0 = 2.2±0.5 MeV/fm3. Neutron skin thicknesses of Rn−Rp = 0.23±0.03 fm and 0.24±0.03 fm for 130Sn and 132Sn, respectively, have been determined. Preliminary results on 68Ni from a similar experiment using an improved setup indicate an enhanced cross section at low energies, while the results for 58Ni are in accordance with results from photoabsorption measurements.
AIP Conference Proceedings. 08/2009; 1165(1):181-184.
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[show abstract]
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ABSTRACT: For the application of the BNCT for the excorporal treatment of organs at the TRIGA Mainz, the basic characteristics of the radiation field in the thermal column as beam geometry, neutron and gamma ray energies, angular distributions, neutron flux, as well as absorbed gamma and neutron doses must be determined in a reproducible way. To determine the mixed irradiation field thermoluminescence detectors (TLD) made of CaF(2):Tm with a newly developed energy-compensation filter system and LiF:Mg,Ti materials with different (6)Li concentrations and different thicknesses as well as thin gold foils were used.
Applied radiation and isotopes: including data, instrumentation and methods for use in agriculture, industry and medicine 04/2009; 67(7-8 Suppl):S242-6. · 1.09 Impact Factor
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G Hampel,
B Wortmann,
M Blaickner,
J Knorr, J V Kratz,
A Lizón Aguilar,
S Minouchehr,
S Nagels,
G Otto,
H Schmidberger,
C Schütz,
L Vogtländer
[show abstract]
[hide abstract]
ABSTRACT: The TRIGA Mark II reactor at the University of Mainz provides ideal conditions for duplicating BNCT treatment as performed in Pavia, Italy, in 2001 and 2003 [Pinelli, T., Zonta, A., Altieri, S., Barni, S., Braghieri, A., Pedroni, P., Bruschi, P., Chiari, P., Ferrari, C., Fossati, F., Nano, R., Ngnitejeu Tata, S., Prati, U., Ricevuti, G., Roveda, L., Zonta, C., 2002. TAOrMINA: from the first idea to the application to the human liver. In: Sauerwein et al. (Eds.), Research and Development in Neutron Capture Therapy. Proceedings of the 10th International Congress on Neutron Capture Therapy, Monduzzi editore, Bologna, pp. 1065-1072]. In order to determine the optimal parameters for the planned therapy and therefore for the design of the thermal column, calculations were conducted using the MCNP-code and the transport code ATTILA. The results of the parameter study as well as a possible configuration for the irradiation of the liver are presented.
Applied radiation and isotopes: including data, instrumentation and methods for use in agriculture, industry and medicine 04/2009; 67(7-8 Suppl):S238-41. · 1.09 Impact Factor
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Yu. Sobolev,
Th. Lauer,
Yu. Borisov,
M. Daum,
N. du Fresne,
L. Göltl,
G. Hampel,
W. Heil,
A. Knecht,
M. Keunecke, J.V. Kratz,
T. Lang,
M. Meister,
Ch. Plonka-Spehr,
Yu. Pokotilovski,
P. Reichert,
U. Schmidt,
Th. Krist,
N. Wiehl,
J. Zenner
[show abstract]
[hide abstract]
ABSTRACT: At the ultracold neutron (UCN) source of the TRIGA research reactor in Mainz, we have measured for the first time the material optical wall-potential of cubic boron nitride. The measurements were performed with a time-of-flight (TOF) spectrometer. The samples investigated had a wall-potential of . This value is in good agreement with the result extracted from neutron reflectometry data and theoretical expectations. Because of its high critical velocity for UCN and its good dielectric characteristics, cubic boron nitride coatings (isotopically enriched) will be useful for a number of applications in UCN experiments.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. 01/2009;
