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ADC Nonlinearity Correction for the Majorana Demonstrator
Imperfections in analog-to-digital conversion (ADC) cannot be ignored when signal digitization requirements demand both wide dynamic range and high resolution, as is the case for the Majorana Demonstrator 76Ge neutrinoless double-beta decay search. Enabling the experiment's high-resolution spectral analysis and efficient pulse shape discrimination required careful measurement and correction of ADC nonlinearities. A simple measurement protocol was developed that did not require sophisticated equipment or lengthy data-taking campaigns. A slope-dependent hysteresis was observed and characterized. A correction applied to digitized waveforms prior to signal processing reduced the differential and integral nonlinearities by an order of magnitude, eliminating these as dominant contributions to the systematic energy uncertainty at the double-beta decay Q value
ORIGAMIX, a CdTe-based spectro-imager development for nuclear applications
The Astrophysics Division of CEA Saclay has a long history in the development
of CdTe based pixelated detection planes for X and gamma-ray astronomy, with
time-resolved imaging and spectrometric capabilities. The last generation,
named Caliste HD, is an all-in-one modular instrument that fulfills
requirements for space applications. Its full-custom front-end electronics is
designed to work over a large energy range from 2 keV to 1 MeV with excellent
spectroscopic performances, in particular between 10 and 100 keV (0.56 keV FWHM
and 0.67 keV FWHM at 13.9 and 59.5 keV). In the frame of the ORIGAMIX project,
a consortium based on research laboratories and industrials has been settled in
order to develop a new generation of gamma camera. The aim is to develop a
system based on the Caliste architecture for post-accidental interventions or
homeland security, but integrating new properties (advanced spectrometry,
hybrid working mode) and suitable for industry. A first prototype was designed
and tested to acquire feedback for further developments. In this study, we
particularly focused on spectrometric performances with high energies and high
fluxes. Therefore, our device was exposed to energies up to 700 keV (133Ba,
137Cs) and we measured the evolution of energy resolution (0.96 keV at 80 keV,
2.18 keV at 356 keV, 3.33 keV at 662 keV). Detection efficiency decreases after
150 keV, as Compton effect becomes dominant. However, CALISTE is also designed
to handle multiple events, enabling Compton scattering reconstruction, which
can drastically improve detection efficiencies and dynamic range for higher
energies up to 1408 keV (22Na, 60Co, 152Eu) within a 1-mm thick detector. In
particular, such spectrometric performances obtained with 152Eu and 60Co were
never measured before with this kind of detector.Comment: Nuclear Instruments and Methods in Physics Research Section A:
Accelerators, Spectrometers, Detectors and Associated Equipment. Available
online 9 January 2015, ISSN 0168-9002
(http://www.sciencedirect.com/science/article/pii/S0168900215000133).
Keywords: CdTe; X-ray; Gamma-ray; Spectrometry; Charge-sharing; Astrophysics
Instrumentation; Nuclear Instrumentation; Gamma-ray camera
Performance of ePix10K, a high dynamic range, gain auto-ranging pixel detector for FELs
ePix10K is a hybrid pixel detector developed at SLAC for demanding
free-electron laser (FEL) applications, providing an ultrahigh dynamic range
(245 eV to 88 MeV) through gain auto-ranging. It has three gain modes (high,
medium and low) and two auto-ranging modes (high-to-low and medium-to-low). The
first ePix10K cameras are built around modules consisting of a sensor flip-chip
bonded to 4 ASICs, resulting in 352x384 pixels of 100 m x 100 m each.
We present results from extensive testing of three ePix10K cameras with FEL
beams at LCLS, resulting in a measured noise floor of 245 eV rms, or 67 e
equivalent noise charge (ENC), and a range of 11000 photons at 8 keV. We
demonstrate the linearity of the response in various gain combinations: fixed
high, fixed medium, fixed low, auto-ranging high to low, and auto-ranging
medium-to-low, while maintaining a low noise (well within the counting
statistics), a very low cross-talk, perfect saturation response at fluxes up to
900 times the maximum range, and acquisition rates of up to 480 Hz. Finally, we
present examples of high dynamic range x-ray imaging spanning more than 4
orders of magnitude dynamic range (from a single photon to 11000
photons/pixel/pulse at 8 keV). Achieving this high performance with only one
auto-ranging switch leads to relatively simple calibration and reconstruction
procedures. The low noise levels allow usage with long integration times at
non-FEL sources. ePix10K cameras leverage the advantages of hybrid pixel
detectors with high production yield and good availability, minimize
development complexity through sharing the hardware, software and DAQ
development with all other versions of ePix cameras, while providing an upgrade
path to 5 kHz, 25 kHz and 100 kHz in three steps over the next few years,
matching the LCLS-II requirements.Comment: 9 pages, 5 figure
Evaluation Of 28nm 10 Bit Adc Using Ramp And Sinusoidal Histogram Methodologies
ADC production testing has become more challenging due to more stringent test procedure for new generation of ADC. The trend for silicon cost is going down while the cost of test is going up. Therefore, to reduce the cost of test and preserve the test accuracy is essential for high volume testing in production. This research is conducted for accurate ADC testing using histogram methodologies. Histogram methodology is the most common test procedure used in high volume production testing. In the past there were a lot of studies on testing the ADC but there were no emphasizing on various histogram methodologies for high volume testing. This research objective is to develop test solutions for 28nm 10 bit ADC using histogram methodologies. The outcome from this research has clearly shows that the test program that has been developed is able to segregate the good and bad devices. 98.18% of the devices are able to pass the ADC testing while remaining 1.82% fail the ADC test. It was found that Ramp Histogram and Sinusoidal Histogram method has achieved this research objective as both methodologies shows similar result based on comparison that has been made. It was known that accurate ADC testing requires large sample size. This research found that multi-site testing was able to compensate the drawback in histogram methodologies. The result shows that multi-site testing is 63.72% more efficient in term of ADC testing time
The Presampler for the Forward and Rear Calorimeter in the ZEUS Detector
The ZEUS detector at HERA has been supplemented with a presampler detector in
front of the forward and rear calorimeters. It consists of a segmented
scintillator array read out with wavelength-shifting fibers. We discuss its
desi gn, construction and performance. Test beam data obtained with a prototype
presampler and the ZEUS prototype calorimeter demonstrate the main function of
this detector, i.e. the correction for the energy lost by an electron
interacting in inactive material in front of the calorimeter.Comment: 20 pages including 16 figure
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