119255637
Geometrical information on the solar shape: high precision results with SDO/HMI
The uncertainty of measurement of solar diameter is depending on the observational time scale. Full-disc images of SDO/HMI and the images from ground observations in Huairou Solar Observing Station have been analyzed to get the values of solar diameter. The satellite observations reach a very high precision, but the absolute image scale still need to be calibrated. The solar oblateness is a more challenging measurement than the diameter, since the signal amplitude is a few milli-arcseconds. It is a relative measurement, then not affected by the pixel scale calibration required by the diameter measurement. But the results are strongly dependent on the state of instrument such as focus plane deformation and on the calculation process.
119266512
Atmospheric fluctuations below 0.1 Hz during drift-scan solar diameter measurements
Measurements of the power spectrum of the seeing in the range 0.001–1 Hz have been
 performed in order to understand the criticity of the transits method for solar diameter
 monitoring.
119291775
Nuclear Shell Structure Evolution Theory
The Self-similar-structure shell model (SSM) comes from the evolution of the conventional shell model (SM) and keeps the energy level of SM single particle harmonic oscillation motion. In SM, single particle motion is the positive harmonic oscillation and in SSM, the single particle motion is the negative harmonic oscillation. In this paper a nuclear evolution equation (NEE) is proposed. NEE describes the nuclear evolution process from gas state to liquid state and reveals the relations among SM, SSM and liquid drop model (DM). Based upon SSM and NEE theory, we propose the solution to long-standing problem of nuclear shell model single particle spin-orbit interaction energy . We demonstrate that the single particle motion in normal nuclear ground state is the negative harmonic oscillation of SSM[1][2][3][4] 
Key words: negative harmonic oscillation, nuclear evolution equation, self-similar shell model
10106778
Crystal structure of the ApbE protein (TM1553) from Thermotoga maritima at 1.58 A resolution.
59430123
Drive Laser and Optical Transport Line for Photoinjector
A Photo-Cathode RF Gun is under development at NSRL. In this paper, the drive laser system is introduced and performance parameters are presented. We adopt a BNL type gun with laser illuminating the cathode at oblique incidence. To correct “time slew” and “elliptical spot” problems arisen on the cathode, an adjustable optical transport line is designed. INTRODUCTION Drive laser system is the key component of photocathode high-brightness injector. To ensure the high quality of electron beams offered for FEL, the injector request a reliable laser with prominent performance parameters, such as: pulse duration, beam profile, energy stability, pulse to pulse stability, pointing stability and phase jitter. We adopted a BNL type gun with p-polarized laser at oblique incidence, as to acquire high quantum efficiency and low thermal emittance [1]. But, the problems of “time slew” and “elliptical spot” will arise on the cathode. To correct them, an adjustable optical transport line was designed. DRIVE LASER SYSTEM We employed a drive laser system developed by High Q Laser Production GmbH [2]. It consisted of three main parts: oscillator with a timing stabilizer, a regenerative amplifier, and the frequency conversion part. Fig.1 is the layout of the drive laser system. Figure 1: Layout of the drive laser system Oscillator The seeding laser is a passive mode-locked laser with a semiconductor absorber mirror (SESAM). Its repetition rate is 102MHz, equal to 1/28 of 2856MHz S-band radio frequency, which is used for RF-gun. The timing stabilizer measure the phase offset between laser pulses and reference RF signal,then adjust the cavity length by putting one laser resonator mirror on a voltage controlled piezo to synchronize the two signals. Regenerative Amplifier The Pockels Cell captures pulses from the continuous seeding laser and determines the pass times of pulse in the regenerative amplifier cavity. The repetition rate of amplified pulses is optional from 10 to 100Hz. Frequency Conversion Part The SHG convert the IR light (1047nm) to green light (523nm), then the FHG convert the green light to UV light (262nm). The conversion efficiency is about 20% from the fundamental to the 4-th harmonics. LASER PERFORMANCE Pulse Duration The autocorrelation measurement result of IR pulse width was 8.3ps FWHW (deconvolved value taken from the Fig.2). The UV pulse width could be close to this value. Figure 2: Pulse width @ 1047 nm measured after Regenerative Amplifier @ 10Hz Beam Profile and Diameter The beam profile and diameter of UV laser pulse was measured by a CCD camera. Beam profile was shown as Fig.3. The beam diameter in X and Y direction were 2.051mm and 1.927mm respectively, which were statistical results of 300 shots. ___________________________________________ *Work supported by the second phase of “985” project hezhg@mail.ustc.edu.cn Proceedings of IPAC’10, Kyoto, Japan TUPEA035 07 Accelerator Technology T24 Lasers 1405 Pulse to Pulse Stability The UV pulse to pulse stability was measured by a photodiode connected with an oscilloscope. The area integration was measured. The fluctuation was calculated as: σ/μ∗100%. The result was about 0.8% over two hours, as shown in Fig.4. Figure 3: Beam profile of UV laser Figure 4: Pulse stability of UV over 2h: measured with 50 Ohm feed-through-terminated input; 500 MHz Bandwidth Tektronix TDS 3052, DC-coupled) Figure 5: Pointing stability measurement Figure 6:Long term energy stability measurement results Pointing Stability Beam pointing stability was measured with a lens of 600mm focal length. The CCD camera was placed at a distance of 700mm from the lens. Pointing stability of the beam centroid were 6.13μrad rms in X direction and 19.31μrad rms in Y direction. Fig.5 showed us the measured pointing stability of centroid point and also peak point. Energy Stability The long term (over 17 hours) energy fluctuation of UV measured by an energy meter was about 0.6% rms, as shown in Fig.6. The measurement precision is dependent on resolution of energy sensor. We think the actual value is higher than the measured one. Phase Jitter The phase jitter between oscillator and reference signal (signal generator: E8257D) was measured. The output signal was presented in Fig.7. Jitter calculation as: 6 0 1 1 14.2 360 102 10 360 rms rms OSC Jitter U mV f Hz = = × ∗ × o 387 rms Jitter fs = Scaling: 1000 1 mV = o To gain a low jitter, a signal generator with low phase noise is required. Signal generators E8257D and E8663B from Agilent are suitable. All of the laser performance parameters were listed on Table 1. OPTICAL TRANSPORT LINE Because of oblique incidence design of BNL type gun, two problems of “time slew” and “elliptical spot” will arise on photo-cathode. To correct them, two prisms were used to add appropriate negative time slew and TUPEA035 Proceedings of IPAC’10, Kyoto, Japan 1406 07 Accelerator Technology T24 Lasers ellipticity on laser pulse wave front. The added time slew is: τ=f(r,α), α is the angle of prism, r is the laser diameter on the prism. A variable beam expander was used to adjust the r . Therefore, the added time slew can be adjustable. The beam diameter on cathode can be controlled by a movable lens at the end of optical line. The Y direction beam diameter was also fore-adjusted by prisms. The sketch of optical transport line was shown as Fig.8. The beam profile after the two prisms was measured by a CCD camera, which was showed in Fig.9. The X direction diameter was compressed to 1.0mm, The Y direction diameter was still about 1.9mm. To compress the Y direction diameter, one just needs to rotate the prisms. The transmission efficiency of the two prisms is about 92%. Figure 7: SYNC-phase output signal, RMS=14.2mV Figure 8: Sketch of optical transport line Figure 9: Beam profile after two prisms Table 1: The performance of drive laser system 1 Wave length/nm 262 2 Pulse duration (FWHM) /ps 8.3 3 Oscillator frequency/MHz 102 4 UV repeat rate/Hz 10-100 5 UV energy/mJ 0-0.65 6 Energy fluctuation/rms 0.6% 7 Pulse to pulse stability/rms 0.8% 8 X direction Point stability/μrad 6.13 9 Y direction Point stability/μrad 19.31 10 Phase jitter/fs 387 11 X direction beam diameter/(1/emm) 2.051 12 Y direction beam diameter/(1/emm) 1.927 SUMMARY We described the drive laser system and presented the measured laser performance parameters. We also reported a preparatory design of optical transport line used to correct “time slew” and “elliptical spot” problems. We are going to reshape the laser pulse. In the aspect of spatial shaping, a commercial production from pi-shaper [3] and GBS-UVH [4] may be considered. Both of them showed favourable shaping effects [5] [6]. In the aspect of temporal shaping, we are going to try the pulse stacking method [6] [7]. REFERENCES [1] Xiang D et al. Nuclear Instruments and Methods in Physics Research A, 2006, (562): 48-52. [2] http://www.highqlaser.at/ [3] http://www.pishaper.com/ [4] http://search.newport.com/?sku=GBS-UV-H [5] D.H. Dowell et al., Proceedings of PAC07, Albuquerque, New Mexico, USA TUPMS058. [6] A.K. Sharma, T, Tsang, and T. Rao, PHYSICAL REVIEW SPECIAL TOPICS ACCELERATORS AND BEAMS 12, 033501 (2009). [7] H. Tomizawa et al., Proceedings of FEL 2007, Novosibirsk, Russia WEBAU01. Proceedings of IPAC’10, Kyoto, Japan TUPEA035 07 Accelerator Technology T24 Lasers 1407
120456002
HEAVY ION THEORY: QCD AND MATTER IN EXTREMIS
Nuclear matter is predicted to undergo a phase transition and become a plasma of quarks and gluons (QGP) at high temperature and density. Recent experimental results from high-energy heavy-ion collisions at the Relativistic Heavy-ion Collider (RHIC) indicate the production of a strongly interacting quark-gluon matter with fluid-like properties. I will discuss some expected features of QCD at high temperature and density, theoretical interpretations of experimental observations and challenges in unraveling some of the basic properties of dense matter in the strongly interacting regime.
14203442
Quantum-classical phase transition of escape rates in biaxial spin particles
By using a stereographic projection of the unit sphere of magnetization vector onto a complex plane for the equations of motion, the effect of an external magnetic field for integrability of the system is discussed. The properties of the Jest solutions and the scattering data are then investigated through introducing transformations other than the Riemann surface in order to avoid double-valued functions of the usual spectral parameter. The exact multisoliton solutions are investigated by means of the Binet-Cauchy formula. The results showed that under the action of an external magnetic field nonlinear magnetization depends essentially on two parameters: its center moves with a constant velocity, while its shape changes with another constant velocity; its amplitude and width vary periodically with time, while its shape is also dependent on time and is unsymmetric with respect to its center. The orientation of the nonlinear magnetization in the plane orthogonal to the anisotropy axis changes with an external magnetic field. The total magnetic momentum and the integral of the motion coincident with its z component depend on time. The mean number of spins derivated from the ground state in a localized magnetic excitations is dependent on time. The asymptotic behavior of multisoliton solutions, the total displacement of center, and the phase shift of the jth peak an also analyzed. [S0163-1829(99)07121-0].