95 research outputs found
Development of a Large-Area Aerogel Cherenkov Counter Onboard BESS
This paper describes the development of a threshold type aerogel Cherenkov
counter with a large sensitive area of 0.6 m to be carried onboard the BESS
rigidity spectrometer to detect cosmic-ray antiprotons. The design incorporates
a large diffusion box containing 46 finemesh photomultipliers, with special
attention being paid to achieving good performance under a magnetic field and
providing sufficient endurance while minimizing material usage. The refractive
index of the aerogel was chosen to be 1.03. By utilizing the muons and protons
accumulated during the cosmic-ray measurements at sea level, a rejection factor
of 10 was obtained against muons with , while keeping 97%
efficiency for protons below the threshold.Comment: 13 pages, LaTex, 9 eps figures included, submitted to NIM
Photodisintegration cross section of ⁴He in the giant dipole resonance energy region
We have performed for the first time the simultaneous measurement of the two-body and three-body photodisintegration cross sections of ⁴He in the energy range from 21.8 to 29.8 MeV using monoenergetic pulsed photons and a 4π time projection chamber containing ⁴He gas as an active target in an event-by-event mode. The photon beam was produced via the Compton backscattering of laser photons with high-energy electrons. The ⁴He(γ,p)³H and ⁴He(γ,n)³He cross sections were found to increase monotonically with energy up to 29.8 MeV, in contrast to the result of a recent theoretical calculation based on the Lorentz integral transform method that predicted a pronounced peak at around 26–27 MeV. The energy dependence of the obtained ⁴He(γ,n)³He cross section up to 26.5 MeV is marginally consistent with a Faddeev-type calculation predicting a flat pattern of the excitation function. The cross section ratio of ⁴4He(γ,p)³H to ⁴He(γ,n)³He is found to be consistent with the expected value for charge symmetry of the strong interaction within the experimental uncertainty in the measured energy range. The present results for the total and two-body cross sections of the photodisintegration of ⁴He are compared to previous experimental data and recent theoretical calculations.Murata M., Kawabata T., Adachi S., et al. Photodisintegration cross section of ⁴He in the giant dipole resonance energy region. Physical Review C 107, 21 (2023); https://doi.org/10.1103/PhysRevC.107.064317
Neutron quadrupole transition strength in C deduced from the C measurement with the MAIKo active target
Elastic and inelastic alpha scatterings on C were measured using a
68-MeV/u radioactive C beam incident on the recently developed MAIKo
active target system. The phenomenological effective - interaction
and the point-nucleon density distribution in the ground state were determined
from the elastic scattering data. The cross sections of the inelastic alpha
scattering were calculated using this interaction and density distribution and
were compared with the experiment to determine the neutron quadrupole
transition matrix element between the ground state and the
state at MeV in C. The deduced neutron transition matrix
element is
fm. The ratio of the neutron transition strength to proton transition
strength was determined as , which indicates that the quadrupole transition
between the ground state and the state in C is less neutron
dominant compared to that in C.Comment: 13 pages, 10 figures, 2 tables. The title and conclusion have changed
from the previous versio
Neutron quadrupole transition strength in deduced from the ^{10}\mathrm{C}(\ensuremath{\alpha},{\ensuremath{\alpha}}^{\ensuremath{'}}) measurement with the MAIKo active target
Elastic and inelastic alpha scatterings on were measured using a 68-MeV/u radioactive beam incident on the recently developed MAIKo active target system. The phenomenological effective α-N interaction and the point-nucleon density distribution in the ground state were determined from the elastic scattering data. The cross sections of the inelastic alpha scattering were calculated using this interaction and density distribution and were compared with the experiment to determine the neutron quadrupole transition matrix element M_n between the ground state and the 2^+_1 state at E_x = 3.35 MeV in . The deduced neutron transition matrix element is M_n = 6.9 ± 0.7(fit) ± 1.2(sys) fm^2. The ratio of the neutron transition strength to proton transition strength was determined as M_n/M_p = 1.05 ± 0.11(fit) ± 0.17(sys), which indicates that the quadrupole transition between the ground state and the 2^+_1 state in is less neutron dominant compared to that in .T. Furuno, T. Kawabata, S. Adachi, Y. Ayyad, Y. Kanada-En'yo, Y. Fujikawa, K. Inaba, M. Murata, H. J. Ong, M. Sferrazza, Y. Takahashi, T. Takeda, I. Tanihata, D. T. Tran, and M. Tsumura, "Neutron quadrupole transition strength in deduced from the ^{10}\mathrm{C}(\ensuremath{\alpha},{\ensuremath{\alpha}}^{\ensuremath{'}}) measurement with the MAIKo active target," Physical Review C, 100, 054322, 2019. https://doi.org/10.1103/PhysRevC.100.054322
Candidates for the 5 condensed state in Ne
We conducted the coincidence measurement of particles inelastically
scattered from Ne at and decay charged particles in order
to search for the alpha-particle condensed state. We compared the measured
excitation-energy spectrum and decay branching ratio with the
statistical-decay-model calculations, and found that the newly observed states
at = 23.6, 21.8, and 21.2 MeV in Ne are strongly coupled to a
candidate for the 4 condensed state in O. This result presents
the first strong evidence that these states are the candidates for the
5 condensed state.Comment: 6 pages, 5 figures. The part of the analysis is updated, and some
discussions are adde
The plasma membrane carbonic anhydrase in murine hepatocytes identified as isozyme XIV
BACKGROUND: Biochemical and histochemical studies have both previously indicated plasma membrane-associated carbonic anhydrase (CA) activity in hepatocytes which has been assumed to be CA IV. However, immunohistochemical data did not support this assignment. Recent northern blotting results indicated the presence of mRNA for the most recently discovered membrane-bound CA isozyme, CA XIV, in the liver. The present study was designed to examine whether CA XIV could contribute to the CA activity described in the hepatocytes. METHODS: Tissue samples from mouse liver were subjected to immunohistochemical staining using the antibodies raised against recombinant mouse CA XIV and CA IV. RT-PCR and western blotting were also performed for CA XIV. RESULTS: A strong immunofluorescent signal was observed in the plasma membrane of mouse hepatocytes. Although CA XIV was expressed on both the apical and basolateral surfaces, the staining was more prominent at the apical (canalicular) membrane domain. The expression of CA XIV in the liver was confirmed by RT-PCR and western blotting. CONCLUSIONS: The presence of CA XIV in the hepatocyte plasma membrane places this novel enzyme at a strategic site to control pH regulation and ion transport between the hepatocytes, sinusoids and bile canaliculi
Search for B+ -> D*+ pi0 decay
We report on a search for the doubly Cabibbo suppressed decay B+ -> D*+ pi0,
based on a data sample of 657 million BBbar pairs collected at the Upsilon(4S)
resonance with the Belle detector at the KEKB asymmetric energy e+ e- collider.
We find no significant signal and set an upper limit of Br(B+ -> D*+ pi0) < 3.6
x 10^-6 at the 90% confidence level. This limit can be used to constrain the
ratio between suppressed and favored B -> D* pi decay amplitudes, r < 0.051, at
the 90% confidence level.Comment: 5pages, 2figures, submitted to PRL (v1); PRL published version (v2:
minor corrections in the text
Purification of chicken carbonic anhydrase isozyme-III (CA-III) and its measurement in White Leghorn chickens
<p>Abstract</p> <p>Background</p> <p>The developmental profile of chicken carbonic anhydrase-III (CA-III) blood levels has not been previously determined or reported. We isolated CA-III from chicken muscle and investigated age-related changes in the levels of CA-III in blood.</p> <p>Methods</p> <p>CA-III was purified from chicken muscle. The levels of CA-III in plasma and erythrocytes from 278 female chickens (aged 1-93 weeks) and 68 male chickens (aged 3-59 weeks) were determined by ELISA.</p> <p>Results</p> <p>The mean level of CA-III in female chicken erythrocytes (1 week old) was 4.6 μg/g of Hb, and the CA-III level did not change until 16 weeks of age. The level then increased until 63 weeks of age (11.8 μg/g of Hb), decreased to 4.7 μg/g of Hb at 73 weeks of age, and increased again until 93 weeks of age (8.6 μg/g of Hb). The mean level of CA-III in erythrocytes from male chickens (3 weeks old) was 2.4 μg/g of Hb, and this level remained steady until 59 weeks of age. The mean plasma level of CA-III in 1-week-old female chickens was 60 ng/mL, and this level was increased at 3 weeks of age (141 ng/mL) and then remained steady until 80 weeks of age (122 ng/mL). The mean plasma level of CA-III in 3-week-old male chickens was 58 ng/mL, and this level remained steady until 59 weeks of age.</p> <p>Conclusion</p> <p>We observed both developmental changes and sex differences in CA-III concentrations in White Leghorn (WL) chicken erythrocytes and plasma. Simple linear regression analysis showed a significant association between the erythrocyte CA-III level and egg-laying rate in WL-chickens 16-63 weeks of age (p < 0.01).</p
First experimental determination of the radiative-decay probability of the 31− state in ¹²C for estimating the triple alpha reaction rate in high temperature environments
The triple alpha reaction is one of the most important reactions in the nuclear astrophysics. However, its reaction rate in high temperature environments at T₉>2 was still uncertain. One of the major origins of the uncertainty was that the radiative-decay probability of the 3⁻₁ state in ¹²C was unknown. In the present work, we have determined the radiative-decay probability of the 3⁻₁ state to be 1.3[+1.2][-1.1] × 10⁻⁶ by measuring the ¹H(¹²C, ¹²Cp) reaction for the first time, and derived the triple alpha reaction rate in high temperature environments from the measured radiative-decay probability. The present result suggests that the 3⁻₁ state noticeably enhances the triple alpha reaction rate although the contribution from the 3⁻₁ state had been assumed to be small
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