Bulletin of the American Physical Society
3rd Joint Meeting of the APS Division of Nuclear Physics and the Physical Society of Japan
Volume 54, Number 10
Tuesday–Saturday, October 13–17, 2009; Waikoloa, Hawaii
Session KE: Instrumentation V |
Hide Abstracts |
Chair: Kyoichiro Ozawa, Tokyo University Room: Kohala 2 |
Saturday, October 17, 2009 9:00AM - 9:15AM |
KE.00001: Large-area silicon photomultipliers as readout candidates for the GlueX experiment Zisis Papandreou, Kathryn Janzen, George Lolos, Andrei Semenov, Carl Zorn The core mission of the GlueX experiment involves a search for exotic hybrid mesons as evidence of gluonic excitations in an effort to understand confinement in QCD. A key subsystem of the GlueX detector is the electromagnetic barrel calorimeter (BCAL) located inside a 2.5~Tesla superconducting solenoid. Due to this arrangement, light sensors are required that can operate in the high magnetic field environment. Among these, Silicon photomultipliers (SiPMs) are very promising candidates as front-end detectors. To date, routine use of SiPMs has been limited to those with an active area of a few mm$^2$. GlueX will require 2300 large-area SiPMs, each composed of sixteen $3\times3$~mm$^2$ cells arranged in a $4\times4$~array for a total area of $\sim$144~mm$^2$ per array. This has placed the GlueX collaboration in the unique position of driving the technology for such larger-area sensors. In this talk I will present tests carried out at Regina and Jefferson Lab regarding performance parameters of prototype SiPM arrays and their micro subcomponents. [Preview Abstract] |
Saturday, October 17, 2009 9:15AM - 9:30AM |
KE.00002: New detector design for combined measurements of omega meson Kazuki Utsunomiya, Kyoichiro Ozawa, Yosuke Watanabe, Shinichi Masumoto, Yusuke Komatsu, Tamotsu Sato, Satoshi Yokkaichi, Kazuya Aoki, Tomoya Tsuji We proposed an experiment at J-PARC for measurements of a direct omega meson mass modification in nucleus. The experiment also aims measuremants of a nuclear bound state. In the experiment, mass of meson in nucleus is measured with omega to pi0 gamma decays and initial conditions in produced omega meson are also measured in p(pi- , n)omega reaction. Produced pi0 meson is detected with two gamma decays. Therefore, two detector are needed such as Gamma detecter and neutron counter. We have developed a TOF type neutron counter. The counter consists of an iron plate and scintillators. This has 4 layers. and 6 scintillators in each lay. To achieve enough mass resolution, time resolution needed to be less than 80 ps. At K1.8 beam line in J-PARC Hadron Hall, the maximum flight path is 7m and the mass resolution of 22 MeV/c2 can be achieved. A Gamma-ray detector is also needed for detecting total three gammas. We perform beam tests and simulations for these two detectors. The result and the present status of detector development and design will be presented. [Preview Abstract] |
Saturday, October 17, 2009 9:30AM - 9:45AM |
KE.00003: A Report on the BETA Detector Package from SANE Jonathan Mulholland The Spin Asymmetries of the Nucleon Experiment measured the parallel and near-perpendicular inclusive double spin asymmetries in an electron scattering experiment using Thomas Jefferson National Laboratory's polarized electron beam and the University of Virginia's polarized frozen ammonia target in Hall C. The experiment ran from January to March of this year, collecting data in a $Q^2$ region from $2.5$ to $6.5$ $GeV^2$ with high Bjorken $x$. Particle detection was accomplished using the Big Electron Telescope Array (BETA), consisting of a forward hodoscope, a gas Cerenkov detector, a Lucite hodoscope, and a lead glass calorimeter. This talk will be a progress report on the data analysis, discussing the calibration of the SANE detector package and the techniques used for tracking particles with this non-magnetic spectrometer. [Preview Abstract] |
Saturday, October 17, 2009 9:45AM - 10:00AM |
KE.00004: Improved Performance \& Future Prospects for Laser-Polarized $^3$He Nuclear Targets Al Tobias, Peter Dolph, Karen Mooney, Vladimir Nelyubin, Jaideep Singh, Gordon Cates High pressure polarized $^3$He gas targets have been used in electron scattering experiments at Bates, SLAC and JLab. The $^3$He nuclei are polarized via spin exchange with an optically pumped alkali metal vapor such as Rb. Light from spectrally narrowed diode lasers results in higher optical pumping rates since the laser is better matched to the Rb absorption line than broadband lasers. A hybrid mixture of K and Rb allows one to take advantage of the more efficient spin exchange between K and $^3$He while still using lasers that are tuned to the Rb D1 line. The combination of narrowed lasers and a hybrid of K and Rb in the cell have allowed $^3$He polarizations to consistantly reach above 60\%, sometimes as high as 70\%, which is significantly better than 40\% typically achieved via pure Rb cells pumped with broadband lasers. Upcoming experiments at JLab will require targets to maintain high polarization even with increased beam current. We'll discuss the prospects of a gold coated metal target chamber which can allow for higher incident beam currents and induced convection of the $^3$He gas in the cell which can reduce beam depolarization effects. [Preview Abstract] |
Saturday, October 17, 2009 10:00AM - 10:15AM |
KE.00005: Development of Green Laser Cavity for Precision Compton Polarimetry in Jefferson Lab Hall A Abdurahim Rakhman, Sirish Nanda, Paul Souder Many experiments at Jefferson Lab require good knowledge of the polarization of the electron beam. The Pb Radius Experiment (PREx) demands polarization measurement of a lower energy (1.0 GeV) electron beam at 1.0 $\%$ accuracy, which can not be achieved by the infra-red (1064 nm) laser Compton polarimeter presently operating in Hall A. Therefore a green laser (CW, 532 nm) based Fabry-P$\acute{e}$rot cavity for upgraded high precision Compton Polarimetry has been proposed and under development. The system used as a high energy polarized photon target for measuring the polarization of a low- to high-energy (1.0 GeV $\sim$ 11.0 GeV) electron beam in a nondestructive manner. Our goal is to amplify a low power laser beam to achieve 1.5 kW of intra cavity power to improve signal to noise ratio of the polarimeter. We locked our test cavity to a frequency doubled Nd:YAG tunable narrow linewidth laser using the Pound-Drever-Hall (PDH) technique. The recent progress and future plan of this project will be presented. [Preview Abstract] |
Saturday, October 17, 2009 10:15AM - 10:30AM |
KE.00006: Performance of a thick windowless He gas target at KUTL R. Iwabuchi, K. Sagara, K. Fujita, T. Teranishi, M. Taniguchi, T. Gotoh, K. Nakano, N. Oba, S. Matsuda, H. Yamaguchi A blow-in type windowless He gas target (BIGT) has been developed at Kyushu University tandem laboratory (KUTL). To increase He target thickness, various trials and efforts have been made for many years. Recently we have achieved 24 Torr of He gas pressure in the central region of the target. This capacity is sufficient for our $^{4}$He($^{12}$C, $^{16}$O)$\gamma $ experiment near the stellar energies, from E$_{cm}$ = 2.4 MeV down to 0.7 MeV. The He target thickness integrated along the beam axis was measured using p + $^{4}$He scattering. Due to the sufficient thickness, a post stripper is not necessarily put downstream the target to make the charge distribution of $^{16}$O equibrium. Performance of this windowless $^{4}$He target is presented. [Preview Abstract] |
Saturday, October 17, 2009 10:30AM - 10:45AM |
KE.00007: Pulse structure dependence of proton spin polarization rate Tomomi Kawahara, Tomohiro Uesaka, Youhei Shimizu, Satoshi Sakaguchi, Takashi Wakui A polarized proton solid target for RI beam experiments has been developed at Center for Nuclear Study, University of Tokyo [1]. The proton is polarized by transferring population difference in photo-excited triplet states of aromatic molecule. Through this method proton polarization of about 20\% have been obtained at 0.1~T and in 100~K. Although this target has been successfully applied to RI beam experiments [2,3], further improvement in the polarization is desirable for future applications. To pursuit possible improvement in photo-excitation power, we have examined pulse-structure dependence of proton polarization rate. The excitation light is provided by a cw Ar-ion laser and pulsed by an optical chopper. We have found that proton polarization depends strongly on the pulse structure and the optimum condition is found to be a duty factor of 50\% and a repetition frequency of 10~kHz. At this condition, the polarization rate can be increased by a factor 2.5 or more compared with the old settings, where a duty factor and a repetition frequency were 5\% and 2.5~kHz, respectively. [1] T. Wakui et al., Nucl. Instrum. Methods A 550 (2005) 521. [2] M. Hatano et al., Eur. Phys. J. A 25 (2005) 255. [3] S. Sakaguchi et al., CNS Annual Report 2006 (2007). [Preview Abstract] |
Saturday, October 17, 2009 10:45AM - 11:00AM |
KE.00008: Measurement of the uniformity of a 1/2 scale prototype magnet for the SNS neutron electric dipole moment experiment Adrian Perez Galvan, Brad Filippone, Justin Chen, Brad Plaster An observation of a neutron electric dipole moment (nEDM) would constrain proposed extensions of the Standard Model and possibly explain the baryon asymmetry of the Universe. A new effort to measure the nEDM using ultra-cold neutrons (UCN) at the Spallation Neutron Source at Oak Ridge National Laboratory is currently underway. The experiment will require a uniform magnetic field as well as stringent control of the magnetic field environment to suppress systematic effects. The uniform magnetic field will be generated by a $Cos(\theta)$ coil inside a series of magnetic shields. We present measurements of the uniformity of the main magnetic field as well as the techniques used to achieve the required specifications of the coil. [Preview Abstract] |
Saturday, October 17, 2009 11:00AM - 11:15AM |
KE.00009: AC loss measurement of high temperature superconducting magnets Kichiji Hatanaka, Mitsuhiro Fukuda, Tetsuhiko Yorita, Takane Saito, Jinta Nakagawa, Yasuhiro Sakemi, Koji Noda, Takeo Kawaguchi Twenty years have passed since the discovery of high temperature superconductivity. However, there not have been many applications of high temperature superconducting (HTS) wires to magnets. In order to investigate the applicability of HTS wires at higher frequencies, two sets of air core magnets were fabricated using a Bi2223 wire and AC loss was measured at 10-21 Hz. Each magnet consists of two coils. Each coil consists of 3 double pancakes and the number of turns is 420 in total. The critical currents were measured at 77 K to be 56 - 62 A for double pancakes and 40 - 43 A after assembling to form coils. The maximum current is assumed to be 200 A at 20 K. Magnets were installed in a cryostat and cooled to 20 K. The critical currents were measured to be 257 A and 282 A for Bx-coil and By- coil, respectively, at 20K. The AC loss was measured at 10, 15 and 21 Hz. AC loss per cycle is independent of the frequency. It is consistent with the hysteresis loss. The loss depends on the 2.4-th power of the applied current. [Preview Abstract] |
Saturday, October 17, 2009 11:15AM - 11:30AM |
KE.00010: Design Tools for FRIB Fragment Separators Laura Bandura A key component of the Facility for Rare Isotope Beams, FRIB will be the in-flight fragment separator used to select and purify the isotope of interest for experiments. In order to simulate this process, we have developed a hybrid map-Monte Carlo code based on the ion optics code COSY INFINITY that accurately models fragment production and atomic processes. The code COSY INFINTIY uses powerful differential algebraic methods for computing the dynamics of the beam in the fragment separator. Ion production and atomic processes have been added to COSY to calculate beam-material interactions. The code tracks the fragmentation and fission of the beam in target and absorber material while computing energy loss and energy and angular straggling as well as charge state evolution of the beam by implementing auxiliary codes such as ATIMA and GLOBAL. EPAX has been utilized to return the cross sections of fragmentation products. The hybrid map-Monte Carlo code extensions added to COSY provide an integrated beam dynamics-nuclear processes design optimization and simulation framework that is efficient and accurate. The code may be used to optimize any fragment separator system for the selection of any rare isotope. [Preview Abstract] |
Saturday, October 17, 2009 11:30AM - 11:45AM |
KE.00011: The Neutron Emission Ratio Observer NERO at the National Superconducting Cyclotron Laboratory Jorge Pereira, Paul Hosmer, Giuseppe Lorusso, Peter Santi, Marcelo Del Santo, Clemens Herlitzius, Karl-Ludwig Kratz, Fernando Montes, Hendrik Schatz, Florian Schertz, Linda Schnorrenberger, Karl Smith, Michael Wiescher The new neutron counter NERO (Neutron Emission Ratio Observer) was built at the National Superconducting Cyclotron Laboratory (NSCL) for measuring $P_{\rm n}$ values of neutron-rich nuclei produced as fast fragmentation beams. The design was motivated by the requirement of being coupled to the NSCL beta counting system, so that $\beta$-decay particles and neutrons emitted from implanted nuclei can be measured simultaneously, while keeping a high efficiency. The detector's performance and main features will be discussed, as well as recent measurements done at NSCL for astrophysical studies of the r-process. [Preview Abstract] |
Saturday, October 17, 2009 11:45AM - 12:00PM |
KE.00012: Background reduction by position reconstruction for CANDLES III Kennsuke Yasuda, Tadafumi Kishimoto, Izumi Ogawa, Saori Umehara, Go Ito, Hidekazu Kakubata, Masaki Miyashita, Kenji Matuoka, Ryuta Hazama CANDLES is the project to search for double beta decay of 48Ca. We use CaF2 crystals as 48Ca sources and scintillation detectors. They are immersed in liquid scintillator. Signals that fire liquid scintillator are backgrounds. Their rejection is achieved by employing pulse shape difference of signals from the CaF2 scintillator and liquid scintillator. In addition to that position resolution helps further to reduce backgrounds. We employed the least squares method to give position of each crystal. We will report the background reduction with a help of position information. [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700