A Generalized Approach to Longitudinal Momentum Determination in Cylindrical Straw Tube Detectors

The upcoming PANDA experiment at FAIR will be among a new generation of particle physics experiments to employ a novel event filtering system realised purely in software, i.e. a software trigger. To educate its triggering decisions, online reconstruction algorithms need to offer outstanding performance in terms of efficiency and track quality. We present a method to reconstruct longitudinal track parameters in PANDA’s Straw Tube Tracker, which is general enough to be easily added to other track finding algorithms that focus on transversal reconstruction. For the pattern recognition part of this method, three approaches are employed and compared: a combinatorial path finding approach, a Hough transformation, and a recursive annealing fit. In a systematic comparison, the recursive annealing fit was found to outperform the other approaches in every category of quality parameters and reaches a reconstruction efficacy of 95% and higher. Due to its computational simplicity, the recursive annealing fit was also found to have faster execution times compared to the other algorithms.

R&D of gas filled detectors for high energy physics experiments

Bose Institute is Asia’s first modern research centre devoted to interdisciplinary research and bears a century old tradition of research excellence. In the experimental high-energy physics (EHEP) detector laboratory of Bose Institute, Kolkata, we are working on the R&D of Gas Electron Multiplier (GEM), straw tube detector for future heavy ion physics experiments and also developing low resistive bakelite Resistive Plate Chamber (RPC), keeping in mind high particle rate handling capacity. The main goal of our research program is the stability study and ageing study of gaseous detectors mentioned above. In this review article, the details of the R&D program of GEM detector, straw tube and RPC detectors carried out during the last five years is reported.

Track Finding for the PANDA Detector Based on Hough Transformations

The PANDA experiment at FAIR (Facility for Antiproton and Ion Research) in Darmstadt is currently under construction. In order to reduce the amount of data collected during operation, it is essential to find as many true tracks as possible and to be able to distinguish them from false tracks. Part of the preparation for the experiment is the development of a fast online track finder. This work presents an online track finding algorithm based on Hough transformations, which is comparable in quality and performance to the currently best offline track finder in PANDA. In contrast to most track finders the algorithm can handle the challenge of extended hits delivered by PANDA’s central Straw Tube Tracker and thus benefit from its precise spatial resolution. Furthermore, optimization methods are presented that improved the ghost ratio as well as the speed of the algorithm by 70 %. Due to further development potential in terms of track finding for secondary particles and speed optimization on GPUs, this algorithm promises to exceed the quality and speed of other track finders developed for PANDA.

Track Reconstruction with PANDA at FAIR

The future PANDA experiment at FAIR aims to investigate a wide range of physics processes in antiproton-proton collisions at rates of up to 20 MHz, while employing a purely software-based event filter. To educate the trigger decisions, a full event reconstruction has to be carried out in real time. This challenge is amplified when considering tracks from particles with long lifetimes and displaced decay vertices, which add to the complexity of the reconstruction algorithms. Here, we present modifications to a cellular automatonbased track finder taking detector time-stamps into account in addition to spatial information, as well as several pattern recognition methods for longitudinal track reconstrucion with PANDA’s Straw Tube Tracker.

Study of the space charge effect in straw tube detectors for the PANDA experiment

The straw tube detectors in the PANDA experiment will work in high particle fluxes reaching up to 25 kHz/cm2. We performed measurement of the gas gain drop in the PANDA straws due to the space charge effect expected at the high particle fluxes. The applied experimental method and obtained results are presented and are compared with calculations of the gas gain drop based on known mobility of positive ions.

Study of the performance of prototypes of straw tube tracker by measuring cosmic rays

Straw tube detector developed for the PANDA experiment in [1], will be used for tracking and identifcation of charged particles in the Forward Tracker (FT). The detector read-out will be incorporated in PANDA DAQ running in trigger-less mode by means of Synchronization Of Data Acquisition Network (SODAnet). SODAnet is the protocol used to synchronize individual detector subsystems by providing a common clock signal and timestamps. The reconstruction of events out of many fragments is done with the Burst Building Network. The first tests of such system have been performed with prototypes of FT and ElectroMagnetic Calorimeter modules (EMC) in [1] measuring cosmic rays. Those tests allow to evaluate the detectors as well as the synchronization and processing systems. The reconstruction of particle tracks has been developed and evaluated. The results on the track reconstruction, spatial resolution and energy loss via Time over Threshold (TOT) method is described together with the DAQ performance.

Longitudinal Tension and Mechanical Stability of a Pressurized Straw Tube

For the development of charged particle detectors based on straw tubes operating in vacuum, a special measurement technique is required for the evaluation of their mechanical properties. A summary of the known equations that govern straw behavior under internal pressure is provided, and a new experimental method of a strained pressurized straw tube study is presented in this paper. The Poisson’s ratio of the straw wall, which defines the stability conditions of a built-in tube, was measured for the NA62 spectrometer straw, and its minimum pre-tension was estimated.