Calorimetry plays a crucial role in modern experimental physics. Calorimeters are essential tools to extract physics in accelerator and non-accelerator experiments. The physics phenomena at the base of cascading processes in matter and the basic principles of calorimeters operation are reviewed at the light of data obtained from running experiments or from sets of dedicated measurements and the constraints from physics requirements. From this understanding comes the possibility of building powerful calorimetric systems with the optimal performances required by future experiments at high-energy and ultrahigh-energy regimes.

https://iopscience.iop.org/article/10.1088/0034-4885/63/4/202/pdf

Physics of cascading shower generation and propagation in matter: principles of high-energy, ultrahigh-energy and compensating calorimetry

Some embodiments of the present invention provide a 2D position-sensitive detector assembly comprising at least three substantially planar detector portions arranged in overlapping relationship as viewed normal to a plane of the detector portions, each detector portion comprising an array of substantially parallel, linear detector elements, the detector elements of respective detector portions being mutually non-parallel, the detector elements each being configured to generate one or more electrical signals in response to interaction of a particle of radiation therewith.

Assembly, apparatus, system and method

A method of reconstructing a 3-dimensional image in a proton transmission computerized tomography (CT) apparatus is disclosed. The method comprises the creation of a reconstruction matrix. The matrix is created by directing a plurality of particles to traverse the object; and for each particle, measuring the trajectory and energy of each particle before and after it has traversed the object; for each particle, calculating the water-equivalent path length within the object; and for each particle, calculating the positions at which it entered and exited the object; and adding the water-equivalent path length, entry and exit positions to the reconstruction matrix. This procedure is repeated from a plurality of angular positions surrounding an object to be imaged. Then, a spatially varying 2-dimensional filter function is applied to the reconstruction matrix. Subsequently, a correction factor is applied to the filtered reconstruction matrix to at least partially correct for the finite extent of the matrix.

Method and apparatus for proton computerised tomography

The condition for obtaining a calorimetric response linear with energy for hadronic showers and an energy resolution that improves as the incident energy increases is the equalization of the electromagnetic (e) and the hadronic (π) signal responses. This equalization is obtained by exploiting a local hardening effect realized through the insertion of low-Z thin plates between the low-Z absorbers and the active material in a hadronic calorimeter with silicon readout. This effect, which allows the reduction of the calorimeter response to the electromagnetic component of the incoming hadronic showers, has been investigated for different low-Z materials. The relevance of some aspects of this study to the radiation hardness of the calorimeters is also addressed.

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Investigation of the local hardening effect produced by various low- Z materials in a Si/(Fe, Pb) electromagnetic calorimeter

In an Si/U hadron calorimeter, using a combination of low-Z and high-Z materials for the absorber allows the reduction of the calorimeter response to the electromagnetic component of the incoming hadronic showers (the local hardening effect). As a result, a ratio varying from e/ pi >1 to e/ pi >

Evidence for compensation and study of lateral shower development in Si/U hadron calorimeters

Experimental evidence has been found for a filtering effect on the soft electron component in electromagnetic showers when combinations of low-Z and high-Z materials are used as absorbers. The filtering effect can be fully exploited to reduce the electromagnetic calorimeter response, making it possible to achieve the compensation condition in a Si/Fe+Pb calorimeter with an effective interaction length almost equal to that of Fe. The action of Fe on Pb, by modifying the critical energy during the electromagnetic shower development, leads to a yield of soft electrons (and very few photons) that are stopped in subsequent absorber layers and/or absorbed by the G10 plates. Recent measurements performed with an enlarged Si/Fe+Pb calorimeter support the idea; the authors have shown that an electromagnetic energy smaller than the hadronic energy is possible once particular FePb configurations are used. >

F. Lamarche

Papers

The compensation condition in hadron calorimeters by the filtering effect