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In this work we report on the performance of the MA-PMT prototype, Hamamatsu H8500C-100 MOD 8, with reduced dynode stages (eight) and super bialkali photocathode (38% Q.E. @ 380 nm). This tube represents the latest technological advancement to improve energy and spatial resolution of gamma imagers. It is particularly suitable for applications involving new high light yield scintillators. To evaluate the performances of this tube, we compared the energy and spatial resolution response with the analogous ones obtained from a standard H8500 MA-PMT coupled to a LaBr 3 :Ce scintillation crystal with the same identity. All measurements were performed with a 64 channel electronic readout. An improvement of about 10% in energy and spatial resolution was found, not properly in agreement with the increased value of quantum efficiency. However, this detector configuration permits to obtain 0.92 mm value of the intrinsic spatial resolution and 7.4% of energy resolution which represent the best results obtained with 4.0 mm thickness continuous LaBr3:Ce crystal.

Tillage is one of the most important operations in the preparation of land for growing crops. Among secondary tillage implements, power harrows, which have a series of PTO-driven rotors which rotate about their vertical axis, are widely adopted in soil-working operations. Typically, this kind of implement is highly energy consuming, due to the heavy mechanical loads required to pull the harrow and the PTO (Power Take-Off) torque needed to drive the rotors. This paper reports the results of extensive in-field experimentation in which the relationship between the operating conditions of a tractor - power harrow system and the mechanical loads (i.e. PTO torque and draught) were investigated in two different test site fields. The test parameters consisted of: nominal tractor speed (3, 6, 9 and 12 km h−1), nominal working depth (6, 9 and 15 cm) and rotor speed (285 and 411 rpm) at a PTO speed of 1000 rpm. The data was statistically analysed by means of a linear mixed effect model to assess the differences in the tractor - harrow system performances measured under different working conditions. The presented results show which operating conditions can be favourable regarding energy and fuel consumption as this information may be very useful to farmers to reduce costs. Moreover, the measured mechanical loads concerning PTO torque and draught may also be beneficial for manufacturers to improve the design of these kinds of implements.

The development of the molecular imaging technique based on radiopharmaceuticals is requiring sophisticated devices with sub-millimeter spatial resolution and high detection efficiency. Recently, in the field of scintillation gamma camera, it has been demonstrated that continuous crystals may improve spatial resolution with respect to the use of scintillation arrays. In this work we propose a new algorithm that improves spatial resolution. It calculates the position from a single scintillation event by squaring the charge collected on a multi-anodes photomultiplier tube (MA-PMT). It is able to remove the position linearity distortion due to the light reflections and the truncations at the crystal edge. We present measurements from a compact gamma camera based on a 51 mm × 51 mm × 4.0 mm LaBr3:Ce continuous scintillation crystal, coupled to a MA-PMT Hamamatsu H8500. The results show a strong improvement in spatial resolution and confirm the high potential in using of LaBr continuous crystal for molecular imaging applications. © 2009 Elsevier B.V. All rights reserved.

Many modern molecular imaging techniques, based on radiopharmaceuticals, can take advantage of sophisticated devices but are still based on the scintillation detector mechanism proposed by Anger. These devices can perform with millimeter spatial resolution and high detection efficiency, but the final performance is strongly affected by the algorithm used for the scintillation position detection. In this work, a detailed comparison of the effect on the imaging performances of three new position detection algorithms, in terms of spatial resolution, detection linearity and useful Field of View is performed on a prototype gamma detector. The detector, built by the authors, is based on a continuous LaBr3:Ce scintillation crystal coupled to an Hamamatsu MA-PMT H8500 and a single anode readout electronics. The experimental data are obtained scanning the detector surface with a Tc99m collimated source (0.4 mm φ) at 1.5 mm step. The overall imaging performances of the device are also tested by mean of a bar phantom. We conclude that the Anger-like algorithms give a 50% uFoV with a 1.30 mm ±0.05 mm spatial resolution while the proposed algorithms give a 80% uFoV and 1.10 mm ±0.06 mm spatial resolution.© 2013 IOP Publishing Ltd and Sissa Medialab srl.

In the last few years, integrated dual-imaging systems have emerged as a new modality for cancer staging with the aim to offer both functional and anatomic information. At moment the prevalent dual modality devices are based on Computer Tomography and Positron Emission Tomography. In this sense, the scientific community is debating about the high effective dose to the patient, representing an indicator of the stochastic risk, especially from Computer Tomography examination. So, a new dual modality imager, based on a Ultrasound probe and a Single Photon Emission Tomography was made in order to combine functional information, from gamma camera with structural one, obtained from the Ultrasound equipment. The Ultrasound probe is the most diffuse anatomical examination device at zero-dose, using a cost-effective and reliable method with few restriction in use. The proposed Single Photon Emission Tomography detector is a compact gamma camera (10x10 cm 2 active area), based on LaBr 3:Ce scintillation crystal coupled to 4x4 array of Hamamatsu H8500C-MOD8 Multi Anode Photomultiplier, with high spatial and energy resolution performances, equipped with rotating slant-hole collimator. A calibration phantom, made of a Co 57 point source inside a water filled box, was utilized to acquire 3D dual modality images. The detector has shown good performances in terms of spatial resolution and localization along z-axis of object of interest. This project was developed by several Italian Universities under an INFN collaboration.