Depth of interaction and bias voltage depenence of the spectral response in a pixellated CdTe detector operating in time-over-threshold mode subjected to monochromatic X-rays

High stopping power is one of the most important figures of merit for X-ray detectors. CdTe is a promising material but suffers from: material defects, non-ideal charge transport and long range X-ray fluorescence. Those factors reduce the image quality and deteriorate spectral information. In this project we used a monochromatic pencil beam collimated through a 20μm pinhole to measure the detector spectral response in dependance on the depth of interaction. The sensor was a 1mm thick CdTe detector with a pixel pitch of 110μm, bump bonded to a Timepix readout chip operating in Time-Over-Threshold mode. The measurements were carried out at the Extreme Conditions beamline I15 of the Diamond Light Source. The beam was entering the sensor at an angle of \texttildelow20 degrees to the surface and then passed through \texttildelow25 pixels before leaving through the bottom of the sensor. The photon energy was tuned to 77keV giving a variation in the beam intensity of about three orders of magnitude along the beam path. Spectra in Time-over-Threshold (ToT) mode were recorded showing each individual interaction. The bias voltage was varied between -30V and -300V to investigate how the electric field affected the spectral information. For this setup it is worth noticing the large impact of fluorescence. At -300V the photo peak and escape peak are of similar height. For high bias voltages the spectra remains clear throughout the whole depth but for lower voltages as -50V, only the bottom part of the sensor carries spectral information. This is an effect of the low hole mobility and the longer range the electrons have to travel in a low field

Quark and Gluon Propagators in Covariant Gauges

We present data for the gluon and quark propagators computed in the standard lattice Landau's gauge and for three values of the covariant gauge-fixing parameter lambda=0,8,16. Our results are obtained using the SU(3) Wilson action in the quenched approximation at beta=6.0 and volume=16^3x32.Comment: Lattice2001(theorydevelop

Numerical Exploration of the RI/MOM Scheme Gauge Dependence

The gauge dependence of some fermion bilinear RI/MOM renormalization constants is studied by comparing data which have been gauge-fixed in two different realizations of the Landau gauge and in a generic covariant gauge. The very good agreement between the various sets of results and the theory indicates that the numerical uncertainty induced by the lattice gauge-fixing procedure is below the statistical errors of our data sample which is of the order of (1-1.5)%.Comment: 3 pages, 2 figures, Lattice2002(theoretical

Customer integration and operational performance: The mediating role of information quality

Much supply chain integration literature tends to be biased towards its positive impact on operational performance. However, inconclusive results demand investigation of the mechanisms through which supply chain integration can lead to superior operational performance. The purpose of this study is to identify empirically the mediating role of information quality on the relationship between customer integration and operational performance, and the direct relationship between customer integration and operational performance. The study is based on a questionnaire sent to 228 manufacturing companies in the Republic of Ireland, and the relationships between the constructs are analyzed through regression analysis. The results indicate that information quality partially mediates the relationship between customer integration and quality, delivery and flexibility. Further, information quality was found to fully mediate the relationship between customer integration and cost

Reparameterization Invariance to all Orders in Heavy Quark Effective Theory

Heavy Quark Effective Theory splits a heavy quark momentum into a large fixed momentum and a variable residual momentum, p = m_Q v + k. It thereby suffers a redundancy of description corresponding to small changes in the choice of the fixed velocity, v. The fact that full QCD is manifestly v-independent should lead to a non-trivial constraint on the form of the effective theory, known as Reparameterization Invariance. For spin-1/2 quarks, the precise form of the constraint and its solution at the level of the effective lagrangian have proven to be rather subtle, and the original proposal by Luke and Manohar has been questioned. In this paper I employ a version of Heavy Quark Effective Theory containing the ``anti-particle'' field as a non-propagating auxiliary field, which greatly simplifies keeping track of v-dependence. This permits a very simple derivation of Reparameterization Invariance from first principles. The auxiliary field can also be integrated out to return to the standard formulation of the effective theory, but with the effective lagrangian now satisfying the full reparameterization constraint. I compare this result with earlier proposals.Comment: 12 pages, LaTex. Important and confusing typographical error in eq. (15) corrected. To appear in Phys. Rev.

Decay constants of heavy pseudoscalar mesons from QCD sum rules

We revisit the sum-rule extraction of the decay constants of the D, Ds, B, and Bs mesons from the two-point correlator of heavy-light pseudoscalar currents. We use the operator product expansion for this correlator expressed in terms of the MSbar heavy-quark mass, for which the perturbative expansion exhibits a reasonable convergence. Our main emphasis is laid on the control over the uncertainties in the decay constants, related both to the input QCD parameters and to the limited accuracy of the method of sum-rules. This becomes possible due to the application of our procedure of extracting hadron observables that involves as novel feature dual thresholds depending on the Borel parameter. For charmed mesons, we find the decay constants f_D=206.2\pm 7.3(OPE)\pm 5.1(syst) MeV and f_Ds=245.3\pm 15.7(OPE)\pm 4.5(syst) MeV. For beauty mesons, the decay constants turn out to be extremely sensitive to the precise value of mb(mb). By requiring our sum-rule estimate to match the average of the lattice results for f_B, a very accurate value mb(mb)=4.245\pm 0.025 GeV is extracted, leading to f_B=193.4\pm 12.3(OPE)\pm 4.3(syst) MeV and f_Bs=232.5\pm 18.6(OPE)\pm 2.4(syst) MeV.Comment: 12 page

Improved reproductive response of sheep in intrauterine insemination program with the use of royal jelly

The objective of the present study was to evaluate estrus and conception rates obtained with the use of progesterone (P4) cream in intravaginal sponges in conjunction with equine chorionic gonadotropin (eCG) or eCG plus royal jelly (RJ) given at the time of sponge withdrawal. A total of 365 fat tailed ewes were assigned randomly to two treatment groups: insertion of intravaginal sponge containing 30 mg (LNP; n = 188) or 60 mg (HNP; n = 177) progesterone for 12 days. For each treatment, 300 or 600 IU of eCG were compared with 100 or 300 IU of eCG plus 500 mg of RJ to assess the effect on reproductive parameters of ewes inseminated laparoscopically in the anoestrus season. Ewes in each group were inseminated with fresh diluted semen (10 × 107 sperm per insemination dose). Inseminations were carried out 11 to 18 h after the first detection of estrus. Pregnancy diagnosis was done at approximately 55 days after insemination. For the 30 and 60 mg natural progesterone treated groups, estrous (22.3 versus 30.5%) and conception rates (50.0% for both treatments) did not differ significantly. Ewes that received 300 IU eCG plus 500 mg RJ had higher (P>0.05) conception rates (66.7 versus 47.6 and 40.0%) than those treated with only eCG (300 or 600 IU) at sponge removal. There was a significant (P≤0.05) delay in onset of estrus in ewes treated with 100 IU eCG plus 500 mg RJ when compared with the other treatment groups.Keywords: Royal jelly, equine chorionic gonadotropin (eCG), natural progesterone, artificial insemination, ew