33 results on '"POLARIZED targets (Nuclear physics)"'
Search Results
2. PLD and PA Take MT1-MMP for a Metastatic Ride.
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Thapa, Narendra and Anderson, Richard A.
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POLARIZED targets (Nuclear physics) , *PHOSPHOLIPASE D , *BREAST cancer , *METASTASIS , *MATRIX metalloproteinases , *PREVENTION - Abstract
Polarized targeting and deposition of MT1-MMP is pivotal for metastasis. In this issue of Developmental Cell , Wang et al. (2017) reveal that a signaling molecule generated by phospholipase D2 drives deposition of MT1-MMP at the site of invadopodia formation and is critical for metastasis in a transgenic breast cancer model. [ABSTRACT FROM AUTHOR]
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- 2017
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3. Circular polarimetry with gamma-ray tracking detectors
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Tashenov, S.
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GAMMA ray polarization , *NUCLEAR track detectors , *BREMSSTRAHLUNG , *COMPTON effect , *PHOTON emission , *POLARIZED targets (Nuclear physics) - Abstract
Abstract: Measurement of circular polarization of gamma-rays with position sensitive solid state detectors is proposed. It is based on the transfer of the photon spin to the recoiled electron in the process of Compton scattering and subsequent detection of the electron spin polarization. Bremsstrahlung polarization correlations, in particular the left–right asymmetry of the photon emission from transversally polarized electrons, are used for this purpose. Compton scattering and electron bremsstrahlung events as well as the scattered and the bremsstrahlung photon absorptions take place inside the active volume of the position sensitive detector. These events are identified and their complete kinematics is reconstructed by means of gamma-ray tracking. No spin polarized targets and no inactive materials are needed for this technique. The proposed method is naturally integrated into the concept of a Compton telescope, allowing for the first time to build an imaging gamma-ray circular polarimeter. It should work in the energy region of several 100keV up to several 10MeV. [Copyright &y& Elsevier]
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- 2011
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4. A highly polarized target for the electron beam at MAMI
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Krimmer, J., Distler, M., Heil, W., Karpuk, S., Kiselev, D., Salhi, Z., and Otten, E.W.
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POLARIZED targets (Nuclear physics) , *ELECTRON beams , *OPTICAL pumping , *ELECTRON scattering , *MICROTRONS , *NEUTRON irradiation - Abstract
Abstract: Polarized from metastability exchange optical pumping (MEOP) is used as an effective polarized neutron target for electron scattering experiments at the MAinz MIcrotron (MAMI). With the present setup an initial polarization of up to 72% has been obtained at the experimental area. A novel calibration technique will be presented which allows the determination of the absolute polarization within a relative uncertainty of 3%. [Copyright &y& Elsevier]
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- 2009
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5. Deuteron frozen-spin- polarized target for nd experiments at the VdG accelerator of Charles University
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Borisov, N.S., Bazhanov, N.A., Belyaev, A.A., Brož, J., Černý, J., Doležal, Z., Fedorov, A.N., Gurevich, G.M., Ivanov, M.P., Kodyš, P., Kubík, P., Kuzmin, E.S., Lazarev, A.B., Lehar, F., Lukhanin, O.O., Matafonov, V.N., Neganov, A.B., Pisarev, I.L., Švejda, J., and Shilov, S.N.
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POLARIZED deuterons , *POLARIZED targets (Nuclear physics) , *POLARIZATION (Nuclear physics) , *NEUTRON beams - Abstract
Abstract: A frozen-spin- polarized deuteron target cooled by the 3He/4He dilution refrigerator is described. Fully deuterated 1,2-propanediol was used as a target material. Deuteron vector polarization about 40% was obtained for the target in the shape of a cylinder of 2-cm diameter and 6-cm length. The target is intended for a study of 3N interactions at the polarized neutron beam generated by the Van de Graaff accelerator at the Charles University in Prague. [Copyright &y& Elsevier]
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- 2008
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6. High precision measurement of the polarization in solid state polarized targets using NMR
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Court, G.R., Houlden, M.A., Bültmann, S., Crabb, D.G., Day, D.B., Prok, Y.A., Penttila, S.I., and Keith, C.D.
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POLARIZED targets (Nuclear physics) , *POLARIZATION (Nuclear physics) , *NUCLEAR magnetic resonance , *PROTONS - Abstract
The factors are reviewed that can affect the systematic uncertainties in CW-NMR measurements of the polarization in solid state polarized targets. The main problem with large signals, typically obtained with protons, is non-linearity arising from failure of the constant RF drive current assumption. The non-linearity can be reduced by operation at lower than normal signal levels. With the much smaller size deuteron signals, a limiting factor may be the instability of the background signal generated by the resonant length cable, used in the standard system. A new system is demonstrated, using non-resonant length cables, which is expected to reduce these uncertainties to a low level. [Copyright &y& Elsevier]
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- 2004
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7. Development of a polarized target for nuclear fusion experiments
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Iio, M., Daito, I., Doshita, N., Hasegawa, T., Horikawa, N., Inagaki, T., Ishii, S., Iwata, T., Kobayashi, T., Kondo, K., Matsuda, T., Okumura, N., Shinba, T., Tagishi, Y., Tajima, Y., Yamaguchi, Y., and Yoshimaru, N.
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POLARIZED targets (Nuclear physics) , *NUCLEAR fusion , *POLARIZATION (Nuclear physics) , *POLYETHYLENE - Abstract
A polarized deuterium target was developed for the use of the first measurement of the so-called complete spin dependent cross-sections of the
&Drarr;(↘,p)T nuclear reaction at20 MeV . In order to minimize the energy losses of incident and emitted particles in the target materials, the target thickness should be as thin as possible. A deuterated polyethylene foil of 30–50 μm thickness was used as polarized target. The deuterons contained in the foil are polarized by the dynamic nuclear polarization method in the magnetic field of2.5 T . The polarized deuterium target system has been installed in the 1st experimental hall of the Tandem Accelerator Center at the University of Tsukuba. From the target asymmetry measurement of&Drarr;(d,d)D elastic scattering by a20 MeV deuteron beam about 10% deuteron target polarization was confirmed. [Copyright &y& Elsevier]- Published
- 2004
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8. Effective densities and polarizations of the targets for the GDH-experiments at MAMI and ELSA
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Rohlof, Ch. and Dutz, H.
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POLARIZATION (Nuclear physics) , *POLARIZED targets (Nuclear physics) , *LOW temperature engineering , *PARTICLES (Nuclear physics) - Abstract
An experimental program has been started at MAMI and ELSA to measure the integrand of the Gerasimov–Drell–Hearn sum rule (GDH) in a photon energy range starting from the pion threshold up to
2.9 GeV . A polarized target has been built, which is based on the frozen spin technique. Since the value of the nucleon polarization and the areal density of the target contribute directly to the result of the GDH-integral both quantities have to be determined with high accuracy. [Copyright &y& Elsevier]- Published
- 2004
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9. Frozen spin solid targets developed at JINR Dubna
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Usov, Yuri
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POLARIZED targets (Nuclear physics) , *LOW temperature engineering , *TARGETS (Nuclear physics) , *RELAXATION (Nuclear physics) - Abstract
Experience with polarized targets and the achievement of very low temperatures at the Laboratory of Nuclear Problems (JINR, Dubna) and at other places have triggered the idea of using a radically new technique based on dissolving
3He in4He to create a frozen spin polarized target. The short history of the development of such proton and deuteron targets at the LNP is given. Diols with the complex Cr(V) are used as target materials. A characteristic feature of these targets is the long relaxation time (≈1000 h ) in magnetic fields of about0.5 T . Lately, the Saclay–Argonne frozen spin polarized proton target used initially in the E704 experiment at FERMILAB has been upgraded by adding the missing parts. A first physics experiment has been carried out. [Copyright &y& Elsevier]- Published
- 2004
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10. Design of internal superconducting holding magnet for the JLAB Hall-B frozen spin polarized target
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Dzyubak, O., Djalali, C., Recalde, N., and Tedeschi, D.
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SUPERCONDUCTING magnets , *POLARIZATION (Nuclear physics) , *POLARIZED targets (Nuclear physics) , *PHOTONUCLEAR reactions - Abstract
We present the results of our investigation of a series of internal holding magnets for longitudinal and transverse polarizations. These magnets will be placed inside a polarizing refrigerator designed for frozen spin targets. The studied magnets will provide the holding field in the range 0.3–
0.5 T . The total thickness of the superconducting coils is of the order0.5 mm . The frozen spin target is under construction for use in photo-nuclear experiments in concert with the JLAB Hall-B CLAS detector. [Copyright &y& Elsevier]- Published
- 2004
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11. The CNS polarized proton solid target for radioactive isotope beam experiments
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Uesaka, T., Hatano, M., Wakui, T., Sakai, H., and Tamii, A.
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POLARIZED targets (Nuclear physics) , *PROTONS , *RADIOISOTOPES , *ZEEMAN effect - Abstract
A polarized proton solid target has been developed at the Center for Nuclear Study, the University of Tokyo. The polarized target makes use of a large population difference among Zeeman sub-levels in the photo-excited triplet state of pentacene. We have successfully applied this polarized target to the first RI beam experiment, where a vector analyzing power for the proton-
6He elastic scattering has been measured. [Copyright &y& Elsevier]- Published
- 2004
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12. New improvements leading to higher polarization frozen spin HD targets at the LEGS facility
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Wei, Xiangdong, Bade, Christopher M., Caracappa, Anthony, Kageya, Tsuneo, Lincoln, Frank C., Lowry, Micheal M., Mahon, John C., Sandorfi, Andrew M., Thorn, Craig E., and Whisnant, C. Steven
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GAMMA ray sources , *LOW temperature engineering , *POLARIZATION (Nuclear physics) , *POLARIZED targets (Nuclear physics) - Abstract
Double polarization experiments at the Laser Electron Gamma Source (LEGS) at Brookhaven National Laboratory have been performed with polarized photon beams and a polarized Hydrogen Deuteride (HD) frozen spin target. After polarizing at
15 T and17 mK and subsequently reaching a frozen spin mode, a target was cold extracted (at2.5 K and0.016 T ) and installed into an In-Beam Cryostat (IBC) which held the target at0.7 T and1.25 K . In-beam relaxation times of 13 days for polarized hydrogen and 36 days for polarized deuterium have been measured. Data were taken with 30% polarized-H and 6% polarized-D, although higher polarization levels have been achieved. Several new improvements are being implemented to improve the operating parameters of polarized HD targets. These include the fabrication of a vibration isolator to lower the polarizing temperature, the purchase of a new IBC to reach longer in-beam relaxation times with higher field and lower temperature (1 T and200 mK ), the construction of a new cold transfer cryostat with a higher field(0.13 T) to reduce polarization loss during target transfers, and the installation of a much improved NMR system for polarization calibration and online monitoring. A summary of the existing data, the ongoing modifications and projection for future performance will be discussed. [Copyright &y& Elsevier]- Published
- 2004
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13. Generating highly polarized nuclear spins in solution using dynamic nuclear polarization
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Wolber, J., Ellner, F., Fridlund, B., Gram, A., Jóhannesson, H., Hansson, G., Hansson, L.H., Lerche, M.H., Månsson, S., Servin, R., Thaning, M., Golman, K., and Ardenkjær-Larsen, J.H.
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NUCLEAR magnetic resonance , *POLARIZED targets (Nuclear physics) , *POLARIZATION (Nuclear physics) , *SOLVENTS - Abstract
A method to generate strongly polarized nuclear spins in solution has been developed, using Dynamic Nuclear Polarization (DNP) at a temperature of
1.2 K , and at a field of3.354 T , corresponding to an electron spin resonance frequency of94 GHz . Trityl radicals are used to directly polarize13C and other low-γ nuclei. Subsequent to the DNP process, the solid sample is dissolved rapidly with a warm solvent to create a solution of molecules with highly polarized nuclear spins. Two main applications are proposed: high-resolution liquid state NMR with enhanced sensitivity, and the use of the hyperpolarized solution as an MR imaging agent. [Copyright &y& Elsevier]- Published
- 2004
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14. Efforts towards a dynamically polarised HD-target
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Radtke, E., Goertz, St., Harmsen, J., Heckmann, J., Meier, A., Meyer, W., and Reicherz, G.
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HYDROGEN isotopes , *POLARIZATION (Nuclear physics) , *POLARIZED targets (Nuclear physics) , *SCATTERING (Physics) - Abstract
The molecular hydrogen isotopes contain no unpolarisable background. From this point of view they appear to be the material of choice for a polarised bulk target in scattering experiments. The fast nuclear relaxation of
H2 andD2 is one reason that these substances are not highly polarisable. This fact brings hydrogendeuteride (HD) into focus. In Bochum a device to freeze out gases into the consisting4He -cryostat has been built up. The principle of the Dynamic Nuclear Polarisation requires a sufficient amount of paramagnetic electrons. These have been produced by cracking HD molecules at1 K using a90Sr β -source with an activity of3.7 GBq . Six days of effective irradiation resulted in a density of paramagnetic centres in the order of1018 spins/cm3 . This could be estimated from bolometric electron paramagnetic resonance (EPR) measurements. Dynamic polarisation could not be achieved. This is accounted to isotopic impurities in the used HD, which accelerate the nuclear relaxation. The constant of ortho–para conversion inH2 could be confirmed to be1.9%/h . [Copyright &y& Elsevier]- Published
- 2004
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15. Performance of the COMPASS polarized target dilution refrigerator
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Doshita, N., Ball, J., Baum, G., Berglund, P., Gautheron, F., Goertz, St., Gustafsson, K., Hasegawa, T., Horikawa, N., Ishimoto, S., Iwata, T., Kisselev, Y., Koivuniemi, J., Kondo, K., Matsuda, T., Meyer, W., Reicherz, G., and Takabayashi, N.
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POLARIZATION (Nuclear physics) , *POLARIZED targets (Nuclear physics) , *LOW temperature engineering , *SCIENTIFIC apparatus & instruments - Abstract
The dynamic nuclear polarization (DNP) of
6LiD requires1 mW/g or more microwave power in the beginning of the process. With the material of350 g , this gives more than350 mW in total for the COMPASS polarized target. A temperature around300 mK or below is needed for an efficient polarization. These low temperatures can only be achieved with a dilution refrigerator designed to operate with a3He flow of100 mmol/s . In order to keep the polarization in the frozen mode, temperatures of about65 mK are used with typical magnetic relaxation times of more than1400 h at0.42 T and of more than15 000 h at2.5 T . Low lattice temperature is important in achieving high nuclear polarization. The base temperature is limited by the heat brought to the mixing chamber by the inlet3He and by radiation and conduction of heat. [Copyright &y& Elsevier]- Published
- 2004
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16. Polarization measurement in the COMPASS polarized target
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Kondo, K., Ball, J., Baum, G., Berglund, P., Doshita, N., Gautheron, F., Goertz, St., Hasegawa, T., Horikawa, N., Ishimoto, S., Iwata, T., Kisselev, Y., Koivuniemi, J., M. LeGoff, J., Magnon, A., Matsuda, T., Meyer, W., and Reicherz, G.
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POLARIZATION (Nuclear physics) , *NUCLEAR magnetic resonance , *POLARIZED targets (Nuclear physics) , *NUCLEAR physics - Abstract
Continuous wave nuclear magnetic resonance (NMR) is used to determine the target polarization in the COMPASS experiment. The system is made of the so-called Liverpool Q-meters, Yale-cards, and VME modules for data taking and system controlling. In 2001 the NMR coils were embedded in the target material, while in 2002 and 2003 the coils were mounted on the outer surface of the target cells to increase the packing factor of the material. Though the error of the measurement became larger with the outer coils than with the inner coils, we have performed stable measurements throughout the COMPASS run time for 3 years. The maximum polarization was
+57% and-53% as the average in the target cells. [Copyright &y& Elsevier]- Published
- 2004
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17. Cryogenic control system of the large COMPASS polarized target
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Gautheron, F., Ball, J., Baum, G., Berglund, P., Doshita, N., Goertz, St., Gustafsson, K., Horikawa, N., Kisselev, Y., Koivuniemi, J., Kondo, K., Meyer, W., and Reicherz, G.
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LOW temperature engineering , *POLARIZED targets (Nuclear physics) , *COMPASS (Orienteering & navigation) , *PROGRAMMABLE controllers - Abstract
The dilution refrigerator used to cool the large COMPASS polarized target is monitored through a PC running
LabVIEWTM 6.1 under Windows2000TM . About 60 parameters of the target (temperatures, pressures, flow rates) are continuously plotted and checked. They are periodically recorded in anOracleTM database and in a data file. An alarm for every parameter can be individually activated and optionally connected to a GSM (Global System for Mobile Communication) delivery message system. A web server receives and publishes the online status of the target with online tables and graphics on a dedicated COMPASS polarized target information web site. A Siemens programmable logic controller (PLC) powered by an uninterruptable source keeps the cryogenic system safe and stable during the long beam periods by controlling valves and interlocks. This safety feature protects the dilution refrigerator against potential damages in case of power failure. [Copyright &y& Elsevier]- Published
- 2004
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18. Highlights of polarized solid state target instrumentation
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Dutz, H.
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LOW temperature engineering , *POLARIZATION (Nuclear physics) , *POLARIZED targets (Nuclear physics) , *PARTICLES (Nuclear physics) - Abstract
Here we will give an overview of the developments in cryogenic and magnet technology used in polarized targets from the roots to nowadays and a brief outlook on new concepts of the polarized target technology for future polarized nuclear and particle physics experiments. [Copyright &y& Elsevier]
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- 2004
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19. Local field in LiD polarized target material
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Kisselev, Y., Ball, J., Baum, G., Berglund, P., Doshita, N., Gautheron, F., Goertz, St., Horikawa, N., Koivuniemi, J., Kondo, K., Magnon, A., Meyer, W., and Reicherz, G.
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POLARIZED targets (Nuclear physics) , *POLARIZATION (Nuclear physics) , *NUCLEAR engineering , *NUCLEAR magnetic resonance - Abstract
We have experimentally studied the first and the second moments of D,
6Li and7Li (I>1/2) NMR lines in a granulated LiD-target material as a function of nuclear polarizations and the data has been compared with a theory elaborated by Abragam, Roinel and Bouffard for monocrystalline samples. The experiments were carried out in the large COMPASS twin-target at CERN. The static local magnetic field of the polarized nuclei was measured by frequency shift between the NMR-signals in the two oppositely polarized cells and lead to the first moment, whereas the investigation of the second moment was done through Gaussian approximation. The average field magnitude in granulated material was estimated 20% larger than the value given by the calculations for monocrystalline samples of cylindrical shape. The second moment shows a qualitative agreement with the theory but it is slightly larger at the negative than at the positive polarization. In a polarized mode, the moments depend on the saturated microwave field. [Copyright &y& Elsevier]- Published
- 2004
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20. NMR line shapes in highly polarized large <f>6LiD</f> target at <f>2.5 T</f>
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Koivuniemi, J., Ball, J., Baum, G., Berglund, P., Doshita, N., Gautheron, F., Goertz, St., Horikawa, N., Kisselev, Y., Kondo, K., Meyer, W., and Reicherz, G.
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NUCLEAR quadrupole resonance , *NUCLEAR magnetic resonance , *POLARIZED targets (Nuclear physics) , *POLARIZATION (Nuclear physics) - Abstract
Due to the vanishing quadrupole interaction only a single narrow
2.8 kHz full-width half-maximum nuclear magnetic resonance (NMR) line is observed in the6LiD target material for deuterium and6Li with spin 1. The second and fourth moments are obtained from a Memory function fit to the measured NMR signal. The values are compared to the calculations from dipole interaction between nuclei. The NMR line shape during polarization up to+ 55% and- 52% is discussed. [Copyright &y& Elsevier]- Published
- 2004
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21. EPR spectroscopy at DNP conditions
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Heckmann, J., Goertz, St., Meyer, W., Radtke, E., and Reicherz, G.
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POLARIZATION (Nuclear physics) , *POLARIZED targets (Nuclear physics) , *ELECTRON paramagnetic resonance spectroscopy , *NUCLEAR engineering instruments - Abstract
In terms of dynamic nuclear polarization (DNP) studies and systematic target material research it is crucial to know the EPR lineshape of the DNP relevant paramagnetic centers. Therefore in Bochum an EPR spectrometer has been implemented into the
4He evaporation DNP facility in order to perform EPR studies at DNP conditions(B=2.5 T ,T=1 K) . The spectrometer hardware and performance as well as first results are presented. [Copyright &y& Elsevier]- Published
- 2004
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22. An experimental approach to the dynamics of nuclear polarisation
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van den Brandt, B., Glättli, H., Grillo, I., Hautle, P., Jouve, H., Kohlbrecher, J., Konter, J.A., Leymarie, E., Mango, S., May, R., Michels, A., Stuhrmann, H.B., and Zimmer, O.
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POLARIZATION (Nuclear physics) , *POLARIZED targets (Nuclear physics) , *NEUTRON scattering , *NUCLEAR physics - Abstract
In the past 3 years a series of experiments have shed new light on the mechanism of dynamic nuclear polarisation (DNP). Time-resolved polarised small-angle neutron scattering and nuclear magnetic resonance have been used simultaneously to study the nuclear polarisation build-up around paramagnetic centres during DNP. This approach, which aims at visualising the nuclear polarisation process on a microscopic scale, shall be exemplified and the experimental techniques used described in some detail. [Copyright &y& Elsevier]
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- 2004
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23. Free radicals and polarized targets
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Bunyatova, E.I.
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FREE radicals , *POLARIZED targets (Nuclear physics) , *NUCLEAR physics , *NUCLEAR engineering instruments - Abstract
Many free radicals were added to organic compounds in search of high proton and deuteron polarizations. Few found practical application. A short review is presented, and special attention is given to some stable nitroxyl radicals which have lately been admixed to organic compounds solid at room temperature, in particular to scintillators. [Copyright &y& Elsevier]
- Published
- 2004
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24. A comparison of NMR concepts for polarization experiments
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Hautle, P.
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POLARIZED targets (Nuclear physics) , *NUCLEAR magnetic resonance , *POLARIZATION (Nuclear physics) , *NUCLEAR physics - Abstract
For a proposed high-accuracy measurement of the spin-dependent neutron scattering length of the deuteron, a precise relative knowledge of the polarization of the proton and deuteron spin systems in the target material is needed. A simulation of the Q-meter system has been performed to get a quantitative estimate of the influence of various causes on the determination of the signal integral. Experimental and theoretical line shapes have been used as input to the model circuit. The response, i.e. the signal output, has been treated in a realistic way (e.g. integral determination, residual baseline fitting) and the effect of circuit parameter drifts has been analyzed. Several Q-meter system setups and measurement modes have been investigated with respect to inherent limitations and sensitivity to parameter drifts. [Copyright &y& Elsevier]
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- 2004
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25. The development of NMR techniques for the high precision measurement of target polarisation
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Court, G.R.
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SOLID state physics , *POLARIZED targets (Nuclear physics) , *NUCLEAR magnetic resonance , *POLARIZATION (Nuclear physics) - Abstract
Solid state polarised targets have been in use in both particle and nuclear physics experiments for nearly 40 years. The vast majority of these experiments have used the continuous wave (CW) NMR technique to measure the target polarisation. The development of this technique over this time period is presented. [Copyright &y& Elsevier]
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- 2004
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26. Observations of radiation damage and recovery in ammonia targets
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McKee, P.M.
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POLARIZED targets (Nuclear physics) , *RADIATION injuries , *AMMONIA , *ELECTRON beams - Abstract
The Polarized Target Group at the University of Virginia has conducted experiments at both the Stanford Linear Accelerator Center (SLAC) and the Thomas Jefferson National Accelerator Facility (JLab) in which a high-intensity (100 nA) electron beam was focused on a polarized target of solid ammonia and/ or solid, deuterated ammonia. Analysis of the target polarization data have revealed several unique characteristics of ammonia. Topics discussed include the rate of polarization decay with accumulated charge, methods of recovering polarization through target annealing and damage-induced shifts in the optimum microwave frequency used to drive the polarization. [Copyright &y& Elsevier]
- Published
- 2004
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27. Ammonia as a polarized solid target material—a review
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Meyer, W.
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AMMONIA , *POLARIZED targets (Nuclear physics) , *NUCLEAR physics , *QUALITY factor meters - Abstract
The enormous efforts towards dynamically polarized ammonia and deuterated ammonia (d-ammonia) with their reasonable high polarizable nucleon contents (quality factor) are reviewed. The early attempts are also a story of failures until a radiation doping method for
NH3 was successfully demonstrated in the end of the 1970s. Some years later the outcome of intense studies and new developments (with pitfalls, too) was the availability of the highly polarizable target materials14NH3 ,15NH3 ,14ND3 and15ND3 , all of them doped for the dynamic nuclear polarization (DNP) by radiation. These materials have been used in new particle physics experiments which, up to that time, suffered either from the lower quality factors or from the modest polarization resistance against radiation damage of the existing alcohol and diol target materials. [Copyright &y& Elsevier]- Published
- 2004
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28. A polarized target for the CLAS detector
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Keith, C.D., Anghinolfi, M., Battaglieri, M., Bosted, P., Branford, D., Bültmann, S., Burkert, V.D., Comer, S.A., Crabb, D.G., De Vita, R., Dodge, G., Fatemi, R., Kashy, D., Kuhn, S.E., Prok, Y., Ripani, M., Seely, M.L., Taiuti, M., and Witherspoon, S.
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POLARIZED targets (Nuclear physics) , *SPIN excitations - Abstract
We describe the design, construction, and performance of a polarized solid target for use in electron scattering experiments with the CEBAF Large Acceptance Spectrometer. Protons and deuterons are continuously polarized by microwave-induced spin–flip transitions at
1 K and5 T . The target operated successfully during two cycles in 1998 and 2000, providing proton and deuteron polarizations as high as 96% and 46%, respectively. The unique features of the target which permit its use inside a4π spectrometer are stressed. Comparison is made between the target polarization measured by the traditional method of NMR and by electron elastic scattering. [Copyright &y& Elsevier]- Published
- 2003
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29. First results of the large COMPASS <f>6LiD</f> polarized target
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Ball, J., Baum, G., Berglund, P., Daito, I., Doshita, N., Gautheron, F., Goertz, St., Harmsen, J., Hasegawa, T., Heckmann, J., Horikawa, N., Iwata, T., Kisselev, Yu., Koivuniemi, J., Kondo, K., Le Goff, J.M., Magnon, A., Meier, A., Meyer, W., and Radtke, E.
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POLARIZED targets (Nuclear physics) , *LITHIUM compounds - Abstract
The COMPASS (NA58) experiment at CERN operates with a large solid polarized target (PT) to study the spin structure of the nucleon. The COMPASS PT system started its operation with the target material
6LiD in 2001. Deuteron polarizations of+54.2% and−47.1% were achieved in a3He/4He dilution refrigerator at a magnetic field of2.5 T . The equal spin temperature (EST) concept was found to hold among the deuteron, the6Li and the7Li nuclei during the dynamic nuclear polarization (DNP) process. The agreement with the EST concept allows the permanent monitoring of only one nuclear species by the nuclear magnetic resonance (NMR) method. [Copyright &y& Elsevier]- Published
- 2003
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30. Time-of-flight measurements in atomic beam devices using adiabatic high frequency transitions and sextupole magnets
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Baumgarten, C., Braun, B., Brunn, I., Court, G., Ciullo, G., Ferretti, P., Golendukhin, A., Graw, G., Haeberli, W., Henoch, M., Hertenberger, R., Koch, N., Kolster, H., Lenisa, P., Nass, A., Pod'yachev, S.P., Reggiani, D., Rith, K., Simani, M.C., and Steffens, E.
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ATOMIC beams , *POLARIZED targets (Nuclear physics) - Abstract
Atomic beam devices are frequently equipped with sextupole magnets to focus the beam or to act as spin filters in combination with RF-transitions for manipulating the hyperfine population within the atomic beam. A useful tool for the analysis of sextupole systems, the application of time-of-flight (TOF) measurements is presented. TOF measurements are enabled without mechanical beam chopper by utilizing adiabatic radio frequency transitions to select atoms within a certain time interval. This method is especially interesting for the use in atomic beam devices that are already equipped with RF-transitions and sextupole magnets and where space limitations or the required quality of the vacuum do not allow the installation of a mechanical chopper. The measurements presented here were performed with the atomic beam polarimeter of the HERMES polarized deuterium target and the results have been used to optimize the sextupole system of the polarimeter. [Copyright &y& Elsevier]
- Published
- 2002
- Full Text
- View/download PDF
31. An atomic beam polarimeter to measure the nuclear polarization in the HERMES gaseous polarized hydrogen and deuterium target
- Author
-
Baumgarten, C., Braun, B., Court, G., Ciullo, G., Ferretti, P., Golendukhin, A., Graw, G., Haeberli, W., Henoch, M., Hertenberger, R., Koch, N., Kolster, H., Lenisa, P., Nass, A., Pod'yachev, S.P., Reggiani, D., Rith, K., Simani, M.C., Steffens, E., and Stewart, J.
- Subjects
- *
POLARIZED targets (Nuclear physics) , *POLARISCOPE , *ATOMIC beams - Abstract
An atomic beam polarimeter for measurement of the hyperfine population numbers and the absolute polarization of thermal atomic hydrogen (H) and deuterium (D) beams is described. The principle of measurement and the method of calibration are given. The polarimeter measures the 4 (6) relative hyperfine population numbers of a thermal H (D) beam in the region of
1013 atoms s−1 to an absolute error of less than 0.01. The polarimeter has been in continuous operation with the internal polarized hydrogen and deuterium gas target used in the HERMES experiment at DESY since 1996. [Copyright &y& Elsevier]- Published
- 2002
- Full Text
- View/download PDF
32. Symmetry breaking effect on determination of polarized and unpolarized parton distributions.
- Author
-
Arbabifar, F., Khorramian, Ali N., Khanpour, H., and Atashbar Tehrani, S.
- Subjects
- *
PARTONS , *POLARIZED targets (Nuclear physics) , *DISTRIBUTION (Probability theory) , *DEEP inelastic collisions , *QUARKS , *PARTICLE density (Nuclear chemistry) - Abstract
Abstract: We perform a new extraction for unpolarized and polarized parton distribution functions considering a flavor decompositions for sea quarks and applying very recent deep inelastic scattering (DIS) and semi inclusive deep inelastic scattering (SIDIS) data in the fixed flavor number scheme (FFNS) framework. In the new symmetry breaking scenario the light quark and antiquark densities are extracted separately and new parametrization forms are determined for them. The heavy flavors contribution, including charm and bottom quarks, are also taken to be account for unpolarized distributions. [Copyright &y& Elsevier]
- Published
- 2013
- Full Text
- View/download PDF
33. Adler Function, DIS sum rules and Crewther Relations
- Author
-
Baikov, P.A., Chetyrkin, K.G., and Kühn, J.H.
- Subjects
- *
PARTICLES (Nuclear physics) , *INELASTIC scattering , *SUM rules (Physics) , *MATHEMATICAL functions , *GAUGE field theory , *POLARIZED targets (Nuclear physics) - Abstract
The current status of the Adler function and two closely related Deep Inelastic Scattering (DIS) sum rules, namely, the Bjorken sum rule for polarized DIS and the Gross-Llewellyn Smith sum rule are briefly reviewed. A new result is presented: an analytical calculation of the coefficient function of the latter sum rule in a generic gauge theory in order . It is demonstrated that the corresponding Crewther relation allows to fix two of three colour structures in the contribution to the singlet part of the Adler function. [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
- View/download PDF
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