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1.
Phys Med Biol ; 62(12): 4946-4969, 2017 Jun 21.
Article in English | MEDLINE | ID: mdl-28402289

ABSTRACT

In order to address dosimetry demands during proton therapy treatments utilizing pencil beam scanning and/or pulsed beam accelerators, we have developed a xenon-filled gas scintillation detector (GSD) that can monitor delivered dose and 2D beam centroid position pulse-by-pulse in real time, with high response linearity up to high instantaneous dose rates. We present design considerations for the GSD and results of beam tests carried out at operating proton therapy clinics. In addition to demonstrating spatial resolution with σ of a few hundred microns in each transverse dimension and relative dose precision better than 1% over large treatment areas, the test beam results also reveal the dependence of the GSD dose normalization on dose rate, beam energy, and gas impurities. The results demonstrate the promise of the GSD technology to provide an important addition to dosimetry approaches for next-generation ion beam therapy.


Subject(s)
Proton Therapy , Radiation Dosage , Scintillation Counting/instrumentation , Xenon , Humans , Radionuclide Imaging , Radiotherapy Dosage
2.
Phys Rev Lett ; 104(13): 132502, 2010 Apr 02.
Article in English | MEDLINE | ID: mdl-20481879

ABSTRACT

We have analyzed data of the DISTO experiment on the exclusive pp --> pLambdaK+ reaction at 2.85 GeV to search for a strongly bound compact K- pp(approximately = X) state to be formed in the pp --> K+ + X reaction. The observed spectra of the K+ missing mass and the pLambda invariant-mass with high transverse momenta of p and K+ revealed a broad distinct peak of 26-sigma confidence with a mass M(X)=2267+/-3(stat)+/-5(syst) MeV/c2 and a width Gamma(X)=118+/-8(stat)+/-10(syst) MeV. The enormously large cross section indicates formation of a compact K- pp with a large binding energy of B(K)=103 MeV, which can be a possible gateway toward cold and dense kaonic nuclear matter.

3.
Phys Rev Lett ; 94(8): 082303, 2005 Mar 04.
Article in English | MEDLINE | ID: mdl-15783880

ABSTRACT

We describe a double-scattering experiment with a novel tagged neutron beam to measure differential cross sections for np backscattering to better than +/-2% absolute precision. The measurement focuses on angles and energies where the cross section magnitude and angle dependence constrain the charged pion-nucleon coupling constant, but existing data show serious discrepancies among themselves and with energy-dependent partial-wave analyses. The present results are in good accord with the partial-wave analyses, but deviate systematically from other recent measurements.

4.
Phys Rev Lett ; 89(9): 092001, 2002 Aug 26.
Article in English | MEDLINE | ID: mdl-12190389

ABSTRACT

Total and differential cross sections for the exclusive reaction pp-->pp rho observed via the pi(+)pi(-) decay channel have been measured at p(beam)=3.67 GeV/c. The observed total meson production cross section is determined to be (23.4+/-0.8+/-8) mu b and is significantly lower than typical cross sections used in model calculations for heavy-ion collisions. The differential cross sections measured indicate a strong anisotropy (approximately cos(theta(CM)(rho)) in the rho(0) meson production.

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