31 research outputs found
A very simple method to measure the input capacitance and the input current of transistors
Abstract We describe a method to measure the gate capacitance and the gate current of transistors at any temperature and at any operating condition. Discrimination between the total input capacitance and transfer reverse capacitance (gate to drain capacitance) is also possible with high accuracy. With this data the optimization of the signal to noise ratio and power dissipation can be achieved in the design of the front-end electronics for nuclear applications
Temperature characterization of deep and shallow defect centers of low noise silicon JFETs
Abstract We have selected different low noise JFET processes that have shown outstanding dynamic and noise performance at both room temperature and low temperatures. We have studied JFETs made with a process optimized for cryogenic operation, testing several devices of varying capacitance. For most of them, we have been able to detect the presence of shallow individual traps at low temperature which create low frequency (LF) GenerationâRecombination (GâR) noise. For one device type no evidence of traps has been observed at the optimum temperature of operation (around 100 K). It had a very small residual LF noise. This device has been cooled down to 14 K. From below 100 K down to 14 K the noise was observed to increase due to GâR noise originating from donor atoms (dopants) inside the channel. A very simple theoretical interpretation confirms the nature of GâR noise from these very shallow trapping centers. We also studied devices from a process optimized for room temperature operation and found noise corresponding to the presence of a single deep level trap. Even for this circumstance the theory was experimentally confirmed. The measurement approach we used allowed us to achieve a very high accuracy in the modeling of the measured GâR noise. The ratio of the density of the atoms responsible for GâR noise above the doping concentration, NT/Nd, has been verified with a sensitivity around 10â7
Regarding âHistopathology and Clinical Outcomes of 151 Women with Postmenopausal Bleeding Treated with Resectoscopic Surgeryâ
No abstract availabl
The front-end readout for CUORICINO, an array of macro-bolometers and MIBETA, an array of Ό-bolometers
The front-end approach for the readout of two arrays of bolometric detectors is described. The first front-end is for an array of m-bolometers, while the second is for an array of macro-bolometers. Analogies and differences in the adopted strategies are put into evidence
Low frequency noise characterization of very large value resistors
A very simple circuit configuration is described which allows to characterize the noise of very large value resistors. With this measurement setup we investigated the low frequency noise of large value resistors, tens of G/spl Omega/ range, realized with different technologies, at different bias voltages. A technique is suggested that allows to reduce the low frequency noise contribution, by optimizing the connecting arrangement. A short review of the resistor noise theory is given
CUORE: A Cryogenic Underground Observatory for Rare Events
CUORE is a proposed tightly packed array of 1000 TeO2 bolometers, each being
a cube 5 cm on a side with a mass of 760 g. The array consists of 25 vertical
towers, arranged in a square of 5 towers by 5 towers, each containing 10 layers
of 4 crystals. The design of the detector is optimized for ultralow-background
searches: for neutrinoless double beta decay of 130Te (33.8% abundance), cold
dark matter, solar axions, and rare nuclear decays. A preliminary experiment
involving 20 crystals 3x3x6 cm3 of 340 g has been completed, and a single CUORE
tower is being constructed as a smaller scale experiment called CUORICINO. The
expected performance and sensitivity, based on Monte Carlo simulations and
extrapolations of present results, are reported.Comment: 39 pages, 12 figures, submitted to NI
First results of the CUORICINO experiment
Preliminary results on double beta decay (DBD) of 130 Te, obtained in the first run of the CUORICINO experiment are presented. The set-up consists of an array of 62 crystals of TeO 2 operating as bolometers in a deep underground dilution unit at a temperature of about 10 mK. Due to a total mass of about 41 kg, CUORICINO represents by far the most massive running cryogenic mass to search for rare events. The achieved lower limit on the neutrinoless DBD is 5.5â
10 23 years, that corresponds to a limit on the Majorana effective mass between 0.37 and 1.9 eV. Performances of the detectors together with the sensitivity estimation are discussed
EP27.07: TV-US prediction of pouch of Douglas obliteration in deep infiltrating endometriosis
no disponibil
Clinical aspects of hysteroscopic diagnosis of atypical endometrial hyperplasia
We read with interest the article by Mittal et al [1], âDiagnostic criteria for distinguishing endometrial adenocarcinoma from endometrial complex atypical hyperplasiaâ. The article is noteworthy not only for diagnostic aspects but also for clinical repercussions.
We report our clinical experience on the diagnostic accuracy of hysteroscopy with regard to atypical endometrial hyperplasia. All hysteroscopies were performed using a continuous-flow office hysteroscope with a 5F working channel. The biopsy forceps has a diameter of 5F and jaws of 5 mm in length. The forceps features small teeth on both sides of the jaws to retain the obtained tissue. With the combination of this kind of forceps and adequate technique, a very large amount of biopsied endometrial tissue (mean, 5.7 mm2 measured in 2 dimensions on histologic section) was sampled [2]. We compared the hysteroscopic findings (including targeted biopsies) with the histologic findings obtained after hysterectomy.
On the basis of histologic examination of endometrial biopsy during a period of 10 years, we had 29 cases of atypical endometrial hyperplasia. Of these, 14 cases (48.3%) were found to be endometrial carcinoma with atypical endometrial hyperplasia at the hysterectomy. All carcinomas were endometrioid carcinomas, except for 1 case of adenosquamous carcinoma. Endometrioid carcinomas were well differentiated except for 2 cases, which were poorly differentiated. The myometrial invasion was present in the inner third of the uterus in 2 cases of endometrioid carcinoma.
In the 14 cases of endometrial carcinoma diagnosed by hysterectomy, the image-based diagnosis by hysteroscopy led to a suspicion of endometrial carcinoma. The biopsies did not confirm the suspicion but revealed an atypical endometrial hyperplasia. The problem may be due to the amount of the biopsy, even when properly executed, because it was performed in a targeted manner.
In our clinical perspective, we appreciate all effort to establish morphological criteria in biopsies to distinguish endometrial adenocarcinoma from atypical endometrial hyperplasia. If there is any doubt and the operator has a suspicion of endometrial cancer, then we will definitely suggest the repetition of the biopsy: this is the peculiarity of hysteroscopy [3]. Other âblindâ techniques of endometrial biopsy (dilatation and curettage, Novak, Vabra, Pipelle) cannot suggest any suspicion and, thereupon, cannot suggest any repetition of the biopsy