3 research outputs found
Fast and Flexible CCD Driver System Using Fast DAC and FPGA
We have developed a completely new type of general-purpose CCD data
acquisition system which enables one to drive any type of CCD using any type of
clocking mode. A CCD driver system widely used before consisted of an analog
multiplexer (MPX), a digital-to-analog converter (DAC), and an operational
amplifier. A DAC is used to determine high and low voltage levels and the MPX
selects each voltage level using a TTL clock. In this kind of driver board, it
is difficult to reduce the noise caused by a short of high and low level in MPX
and also to select many kinds of different voltage levels. Recent developments
in semiconductor IC enable us to use a very fast sampling ( 10MHz) DAC
with low cost. We thus develop the new driver system using a fast DAC in order
to determine both the voltage level of the clock and the clocking timing. We
use FPGA (Field Programmable Gate Array) to control the DAC. We have
constructed the data acquisition system and found that the CCD functions well
with our new system. The energy resolution of Mn K has a full-width at
half-maximum of 150 eV and the readout noise of our system is
8 e.Comment: 12 pages, 7 figures, Accepted for Nuclear Instruments and Method in
Physics Researc
Extra-Dimensions effects on the fermion-induced quantum energy in the presence of a constant magnetic field
We consider a U(1) gauge field theory with fermion fields (or with scalar
fields) that live in a space with extra compact dimensions, and we
compute the fermion-induced quantum energy in the presence of a constant
magnetic field, which is directed towards the x_3 axis. Our motivation is to
study the effect of extra dimensions on the asymptotic behavior of the quantum
energy in the strong field limit (eB>>M^{2}), where M=1/R. We see that the weak
logarithmic growth of the quantum energy for four dimensions, is modified by a
rapid power growth in the case of the extra dimensions.Comment: 18 pages, 4 figures, 2 tables, several correction
The X-ray CCD camera of the MAXI Experiment on the ISS/JEM
MAXI, Monitor of All-sky X-ray Image, is the X-ray observatory on the
Japanese experimental module (JEM) Exposed Facility (EF) on the International
Space Station (ISS). MAXI is a slit scanning camera which consists of two kinds
of X-ray detectors: one is a one-dimensional position-sensitive proportional
counter with a total area of , the Gas Slit Camera (GSC), and
the other is an X-ray CCD array with a total area , the
Solid-state Slit Camera (SSC). The GSC subtends a field of view with an angular
dimension of 1 while the SSC subtends a field of view
with an angular dimension of 1 times a little less than 180. In
the course of one station orbit, MAXI can scan almost the entire sky with a
precision of 1 and with an X-ray energy range of 0.5-30 keV. We have
developed the engineering model of CCD chips and the analogue electronics for
the SSC. The energy resolution of EM CCD for Mn K has a full-width at
half maximum of 182 eV. Readout noise is 11 e^- rms.Comment: 10 pages, 4 figures Accepted for Nuclear Instruments and Method in
Physics Researc