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Journal Articles

Event structure and double helicity asymmetry in jet production from polarized $$p + p$$ collisions at $$sqrt{s}$$ = 200 GeV

Adare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Y.*; Al-Bataineh, H.*; Alexander, J.*; Aoki, K.*; Aphecetche, L.*; Armendariz, R.*; et al.

Physical Review D, 84(1), p.012006_1 - 012006_18, 2011/07

https://doi.org/10.1103/PhysRevD.84.012006
 Times Cited Count：29 Percentile：72.31(Astronomy & Astrophysics)

We report on the event structure and double helicity asymmetry ($$A_{LL}$$) of jet production in longitudinally polarized $$p + p$$ collisions at $$sqrt{s}$$ = 200 GeV. Photons and charged particles were measured by the PHENIX experiment. Event structure was compared with the results from PYTHIA event generator. The production rate of reconstructed jets is satisfactorily reproduced with the next-to-leading-order perturbative QCD calculation. We measured $$A_{LL}$$ = -0.0014 $$pm$$ 0.0037 at the lowest $$P_T$$ bin and -0.0181 $$pm$$ 0.0282 at the highest $$P_T$$ bin. The measured $$A_{LL}$$ is compared with the predictions that assume various $$Delta G(x)$$ distributions.

Journal Articles

Identified charged hadron production in $$p + p$$ collisions at $$sqrt{s}$$ = 200 and 62.4 GeV

Adare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Yasuyuki*; Al-Bataineh, H.*; Alexander, J.*; Aoki, Kazuya*; Aphecetche, L.*; Armendariz, R.*; et al.

Physical Review C, 83(6), p.064903_1 - 064903_29, 2011/06

https://doi.org/10.1103/PhysRevC.83.064903
 Times Cited Count：184 Percentile：99.44(Physics, Nuclear)

Transverse momentum distributions and yields for $$pi^{pm}, K^{pm}, p$$, and $$bar{p}$$ in $$p + p$$ collisions at $$sqrt{s}$$ = 200 and 62.4 GeV at midrapidity are measured by the PHENIX experiment at the RHIC. We present the inverse slope parameter, mean transverse momentum, and yield per unit rapidity at each energy, and compare them to other measurements at different $$sqrt{s}$$ collisions. We also present the scaling properties such as $$m_T$$ and $$x_T$$ scaling and discuss the mechanism of the particle production in $$p + p$$ collisions. The measured spectra are compared to next-to-leading order perturbative QCD calculations.

Journal Articles

Measurement of neutral mesons in $$p$$ + $$p$$ collisions at $$sqrt{s}$$ = 200 GeV and scaling properties of hadron production

Adare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Y.*; Al-Bataineh, H.*; Alexander, J.*; Aoki, K.*; Aphecetche, L.*; Armendariz, R.*; et al.

Physical Review D, 83(5), p.052004_1 - 052004_26, 2011/03

https://doi.org/10.1103/PhysRevD.83.052004
 Times Cited Count：175 Percentile：98.48(Astronomy & Astrophysics)

The PHENIX experiment at RHIC has measured the invariant differential cross section for production of $$K^0_s$$, $$omega$$, $$eta'$$ and $$phi$$ mesons in $$p + p$$ collisions at $$sqrt{s}$$ = 200 GeV. The spectral shapes of all hadron transverse momentum distributions are well described by a Tsallis distribution functional form with only two parameters, $$n$$ and $$T$$, determining the high $$p_T$$ and characterizing the low $$p_T$$ regions for the spectra, respectively. The integrated invariant cross sections calculated from the fitted distributions are found to be consistent with existing measurements and with statistical model predictions.

JAEA Reports

Data Base of Critical Experiments in Deuterium Critical Assembly

Hazama, Taira; Kono, Naomi; Horikiri, Morito; Sato, Seiji*; Hachiya, Yuki*; Hosoda, Atsushi*

JNC TN9450 2003-005, 908 Pages, 2003/06

JNC-TN9450-2003-005.pdf:38.35MB

None

Journal Articles

Axial Dependence of Partial Void Reactivity in a Light Water-Cooled, Heavy Water-Moderated, Pressure-Tube Reactor

Aihara, Nagafumi; Fukumura, Nobuo; Kadotani, Hiroyuki*; Hachiya, Yuki

Nuclear Science and Engineering, 109, p.158 - 170, 1991/00

https://doi.org/10.13182/NSE91-A28515
 Times Cited Count：4 Percentile：47.84(Nuclear Science & Technology)

None

JAEA Reports

None

Hachiya, Yuki

PNC TN9530 89-012, 48 Pages, 1989/03

PNC-TN9530-89-012.pdf:1.56MB

no abstracts in English

JAEA Reports

None

Hachiya, Yuki

PNC TN9530 88-020, 54 Pages, 1988/03

PNC-TN9530-88-020.pdf:2.0MB

no abstracts in English

JAEA Reports

None

*; Hachiya, Yuki*

PNC TN908 85-04, 14 Pages, 1985/08

PNC-TN908-85-04.pdf:0.32MB

None

JAEA Reports

Dependence of coolant void coefficient on control rod insertion length

Fukumura, Nobuo*; Hachiya, Yuki*; *

PNC TN941 84-106, 70 Pages, 1984/01

PNC-TN941-84-106.pdf:1.65MB

The analysis of coolant void coefficient for the FUGEN core has been done in order to clarify the phenomena of shifting the coefficient to negative side by inserting control rods. The beginning of 4th cycle core of FUGEN (BOC) was chosen because the coolant void coefficient was measured by changing the control rod pattern for that core. The analysis has been made by use of the detailed core calculation code system "PHLOX". Thermohydraulic characteristics for the analysis of coolant void coefficient have been derived from the axial power distribution obtained by the actual readings of local power monitor (LPM) with the use of thermohydraulic code HAPI-II. Three dimensional cell constants have been obtained by use of both the thermohydraulic characteristics and the burnup distribution. The core eigenvalue before or after the changing of recirculation pump (RCP) speed has been obtained from the three dimensional core calculation. The coolant void coefficient has been derived from these eigenvalues. The followings have been obtained from the present analysis: (1)The value of coolant void coefficient when the control rods are halfly inserted ($$sim$$41%) shifts to negative side about 1.5$$times$$10$$^{-5}$$$$Delta$$k/k/% void as compared with the value when the control rods are shallowly inserted ($$sim$$65%). (2)The value of coolant void coefficient when the control rods are deeply inserted ($$sim$$26%) shifts to negative side about 3 $$times$$10$$^{-5}$$$$Delta$$k/k/% void as compared with the value when the control rods are shallowly inserted ($$sim$$65%). (3)From the above two facts it is clear that the reasonable value of the coolant void coefficient can be obtained by increasing the value of power peaking factor through the big change of power distribution and through large leakage of neutrons by use of the reasonable control rod pattern.

JAEA Reports

Measurements and analysises of lattice parametets in 36-rod PuO$$_{2}$$-UO$$_{2}$$ fuel clusters

Fukumura, Nobuo*; *; *; *; *; *; Hachiya, Yuki*

PNC TN941 82-132, 54 Pages, 1982/06

PNC-TN941-82-132.pdf:1.28MB

Measurements and analysises of lattice parameters have been made by use of the 36-rod PuO$$_{2}$$-UO$$_{2}$$ fuel clusters (0.54w/o PuO$$_{2}$$-UO$$_{2}$$) which are composed of the rods with the same diameters as the ones of Fugen type fuel rods. The nine 36-rod fuel clusters were loaded in the central region of the DCA eore with the square lattice of 25.0cm pitch and the surrounding region was occupied with eighty-eight 1.2w/o enriched UO$$_{2}$$ 28-rod fuel clusters. The experiments have been performed with (0% void)and without (100% void) H$$_{2}$$O coolant in the pressure tube. The lattice parameters such as $$^{238}$$U resonance capture ratio ($$rho$$$$^{28}$$), the epicadmium fission ratio of $$^{235}$$U or $$^{239}$$Pu ($$delta$$$$^{25}$$ or $$delta$$$$^{49}$$), the fast fission ratio of $$^{238}$$U ($$delta$$$$^{28}$$) and the fission ratio of $$^{239}$$Pu to $$^{235}$$U ($$delta$$$$^{49}$$$$_{25}$$) were obtained by the foil activation method using foils of plutonium and enriched, natural and depleted uranium. The analysises have been made by use of the sophisticated cell calculation code WIMS which is used for nuclear design of the commercial FUGEN. The results are shown in the table. Here, indices "cell" represent cell averaged values. It is concluded from these results that the code WIMS understimates the fission reaction rates of $$^{238}$$U, $$^{235}$$U and $$^{239}$$Pu, and capture reaction rates of $$^{238}$$U resonanee.

Journal Articles

Fuel Temperature Coefficients of Reactivity for Heavy-Water-Moderated, Cluster-Type Fuel Lattices

Hachiya, Yuki; Sakata, Hajime*; *

Journal of Nuclear Science and Technology, 17(10), p.747 - 763, 1980/10

https://doi.org/10.1080/18811248.1980.9732651

JAEA Reports

Measurements of intra-cell thermal neutron flux distributions in plutonium fuel lattices; Experiment on 25.0 cm pitch lattice

*; *; *; *; *; Hachiya, Yuki*

PNC TN941 79-149, 76 Pages, 1979/09

PNC-TN941-79-149.pdf:1.5MB

Intra-cell thermal neutron flux distributions have been measured in plutonium fuel lattices at 25.0 cm pitch by means of dysprosium foil activation method. Enrichments of PuO$$_{2}$$ in PuO$$_{2}$$-UO$$_{2}$$ fuels used are 0.54 wt% and 0.87 wt%. The measurements on 0.54 wt% enriched Pu0$$_{2}$$-UO$$_{2}$$ fuel lattices were made using air, light water or D$$_{2}$$O-H$$_{2}$$O-H$$_{3}$$BO$$_{3}$$ mixture containg $$sim$$ 37 wt% of D$$_{2}$$O, as coolants. Those on 0.87 wt% enriched PuO$$_{2}$$-UO$$_{2}$$ fuel lattices were made using air or light water. The effect of $$^{10}$$B in D$$_{2}$$O moderator on the thermal neutron flux distribution was also investigated in 0.54 wt% enriched PuO$$_{2}$$-UO$$_{2}$$ fuel lattice with H$$_{2}$$O coolant and D$$_{2}$$O moderator containg $$^{10}$$B by 3.9 ppm. Measurement uncertainty in the present experiment is $$pm$$2 %, which is almost the same as that in the experiment on plutonium lattices at 22.5 cm pitch. To scrutinize dependence of flux distribution on lattice pitch, the results of the present experiment were compared with those of the experiments on 22.5 cm-pitch lattices which had been already made. The calculations by the code LAMP-DCA agrees with the experiment within $$sim$$ 2 %.

JAEA Reports

Measurement of intra-cell thermal neutron flux distributions for plutonium fuel lattices; Experiments on 22.5cm pitch lattice

*; *; Fukumura, Nobuo*; Hachiya, Yuki*

PNC TN941 75-112, 134 Pages, 1975/12

PNC-TN941-75-112.pdf:2.88MB

Intra-cell thermal neutron flux distributions have been measured in plutonium fuels loaded in 22.5cm pitch lattice by means of dysprosium foil activation method. Coolant void fractions used in the experiment were 0%, 30%, 70% and 100% for the plutonium fuel lattice of 0.54w/o PuO$$_{2}$$-UO$$_{2}$$. And 0% and 100% void fractions were used in 0.87w/o PuO$$_{2}$$-UO$$_{2}$$ fuel (standard grade) and 0.87w/o PuO$$_{2}$$-UO$$_{2}$$ fuel (reactor grade). Experimental results were compared with the values calculated by NOAH-II code and LAMP-DCA code. Measurement positions were in the plutonium fuel pins, in the coolant, on both inside and outside surfaces of pressure tube and calandria tube, and in the D$$_{2}$$O moderator. Experimental errors for the resultant Dy activities were estimated as $$pm$$2.0%. On the base of this accurate measurement, thermal neutron flux distributions became to be comparable in detail in each regions with results calculated by various codes. The experimental values agree with the calculated values by LAMP-DCA code better than the results by NOAH-II code.

JAEA Reports

Analysis of fuel temperature coefficient of reactivity with two-region core system

Kadotani, Hiroyuki*; Hachiya, Yuki*; *

PNC TN941 75-59, 37 Pages, 1975/05

PNC-TN941-75-59.pdf:0.84MB

Fuel temperature coefficients of reactivity have been analysed for DCA core with a central channel of raised temperature. The present model for the analysis of the experiment is based on the following two considerations ;(1)a large difference of nuclear characteristics between the central channel that is made of stainless steel and the outer channels of aluminum in the driver region, (2)a slight change in neutron temperature of the high temperature region where there is no moderating material. Fuel temerature coefficients of reactivity obtained by the present analysis and the experimental results are listed in the following table. [Table Temperature coefficient of reactivity in two-region (central test channel and l.2% UO$$_{2}$$ driver channels) core] The present analysis explains successfully the qualitative features of the experiment, including dependencies of temperature coefficients on fuel enrichment and temperature range, and the linear coefficient of cladding material. The quantitative agreement, however, is not so good except for l,5% UO$$_{2}$$ fuel.

JAEA Reports

Decrease in power peaking in a cluster of different enrichment fuel pins measurement with foil activation method

*; *; *; Hachiya, Yuki*

PNC TN941 75-47, 26 Pages, 1975/05

PNC-TN941-75-47.pdf:0.83MB

In order to study feasibility of the decreasing local power peaking factor, a special type of cluster was assembled by arranging 0.87% enriched PuO$$_{2}$$-UO$$_{2}$$ fuel pins in the inner two layers and 0.54% pins in the outer, among three concentric layers of a cluster. Nine of such clusters with H$$_{2}$$O coolant (0% voidage) were loaded in the central region of DCA core of 22.5 cm lattice pitch and 1.2% enriched UO$$_{2}$$ fuel clusters in the surrounding region. Measurement was made in the central channel (fuel cluster) of the core. In contrast to the usual method of measuring local power peaking factor $$<$$LPF$$>$$ by direct $$gamma$$-ray scanning of fuel pins, power contribution from each nuclei $$^{235}$$U of $$^{239}$$Pu has been specified by present foil activation method using high-enriched uranium and plutonium foils. The resultant factor $$<$$LPF$$>$$ of the different enrichment fuel pins' cluster was obtained as follows. $$<$$LPF$$>$$ = 1.08$$pm$$0.02 This value is favorably less than that of the ordinary uniform arrangement cluster of 0.54% or 0.87% PuO$$_{2}$$-UO$$_{2}$$ fuel pxns. Calculational value by NOAH-II code is 1.11 and the value is overestimated by 2.8% of the experimental one. This discrepancy is explained due to little dependence of $$^{239}$$Pu absorption cross section on thermal neutron spectrum in the NOAH-II calculation, because in the present experiment it was revealed that the cross section (in the form of ratio of $$^{239}$$Pu to $$^{235}$$U fissions) depends largely on thermal neutron energy spectrum.

JAEA Reports

Measurement of material bucklings in cluster-type fuel cores

*; Hachiya, Yuki*; Fukumura, Nobuo*

PNC TN941 74-82, 116 Pages, 1974/12

PNC-TN941-74-82.pdf:2.56MB

The fitting method of flux distribution was investigated to obtain material bucklings in cluster-type fuel cores in comparison with calculated values by METHUSELAH-II code and experimental values by the subsititution method. As the results, it can be considered that the fitting method developed in the present work for measurement of material buckling in cluster-type fuel core has been established. This method will be used various core configurations, especially 2-region core configuration.

JAEA Reports

Measurements of intra-cell thermal neutron flux distributions for plutonium fuel lattice (II)

*; Fukumura, Nobuo*; *; Hachiya, Yuki*

PNC TN941 74-77, 48 Pages, 1974/11

PNC-TN941-74-77.pdf:1.07MB

Intra-cell thermal neutron flux distributions in 0.87 w/o PuO$$_{2}$$-UO$$_{2}$$ fuel (standard grade) loaded in 22.5 cm pitch lattice have been measured by means of dysprosium foil activation method for coolant void fractions of 0 % and 100 %. The results are compared with the results in 0.54 w/o PuO$$_{2}$$-UO$$_{2}$$ fuel and the values calculated by NOAH-II code. Accuracy of the present experiments is found almost the same as that of 0.54 w/o PuO$$_{2}$$-UO$$_{2}$$ fuel experiments. Therefore, it can be considered that the experimental method specially developed for measurement of intra-cell thermal neutron flux distributions on plutonium fuel has been established. The experimental result for coolant void fraction of 0 % agrees with the calculated value bettter than that for 100 %.

JAEA Reports

Measurements of intra-cell thermal neutron flux Distributions for plutonium fuel lattice (I)

*; *; Hachiya, Yuki*; Fukumura, Nobuo*; *

PNC TN941 74-26, 46 Pages, 1974/06

PNC-TN941-74-26.pdf:1.26MB

Intra-cell thermal neutron flux distributions in 0.54 w/o PuO$$_{2}$$-UO$$_{2}$$ fuel loaded in 22.5 cm pitch lattice have been measured by means of dysprosium foil activation method for coolant void fractions of 0 %, 30%, 70% and 100%. These results are compared with values calculated by NOAH-II code. Thermal neutron flux distributions in D$$_{2}$$O moderator region were measureed with better accuracy ($$pm$$1.5%) with a new experimental technique. Measurements at the inside and outside of a pressure tube and a calandria tube were made with a foil handling technique which had been developed in the present experiment. As a result, the detailed comparison of thermal neutron flux distributions in the pressure and the calandria tube with the calculation could be performed. The experimental result for coolant void fraction of 100 % agrees with the calculated value better than the results for 0 %, 30% and 70%.

18 (Records 1-18 displayed on this page)
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