H. Czyrkowski

Development of calorimeters using thin chambers operating in a high gain mode

Abstract A new type of thin multiwire proportional chamber detector operating in a high gain mode has been developed. Its characteristics have been optimized for calorimetric use. Two setups consisting of ten such detectors (electromagnetic calorimeter) interlaced with lead plates of 6 mm thickness and with iron plates of 8 cm thickness (hadron calorimeter) were tested. The characteristics of these detectors operating in calorimetric environments have been investigated and compared with theoretical expectations.

Pattern Comparator Trigger (PACT) for the muon system of the CMS experiment

The general scheme for the fast, pipelined first level trigger on high pt muons in the CMS detector at LHC is presented. The prototype PACT system was tested in the high momentum muon beams in the RD5 experiment during 1993/94 runs. The obtained efficiency curves are shown.

“Pi of the Sky” Detector

“Pi of the Sky” experiment has been designed for continuous observations of a large part of the sky, in search for astrophysical phenomena characterized by short timescales, especially for prompt optical counterparts of Gamma Ray Bursts (GRBs). Other scientific goals include searching for novae and supernovae stars and monitoring of blasars and AGNs activity. “Pi of the Sky” is a fully autonomous, robotic detector, which can operate for long periods of time without a human supervision. A crucial element of the detector is an advanced software for real-time data analysis and identification of short optical transients. The most important result so far has been an independent detection and observation of the prompt optical emission of the “naked-eye” GRB080319B.

Optimization of FPGA processing of GEM detector signal

This paper presents analysis of processing method of the signal from Gas Electron Multiplier (GEM) detector acquired in our Field-Programmable Gate Array (FPGA) based readout system. We have found that simple processing of GEM signal received from the charge amplifier, sampled at 100MHz with 10-bit resolution, after low-pass filtering with 15 MHz cut-off frequency, provides accuracy similar to obtained by processing of the raw GEM signal sampled at 2.5 GHz frequency with 8-bit resolution. Even when 3 bits are lost due to long term instability of the detector and analog part of the system - resulting in 7-bit effective resolution, the reasonable accuracy is still preserved. Additionally we have analyzed computational power required to perform the real-time analysis of the GEM signal, taking into consideration resources offered by the FPGA chip used in the prototype platform.

Readout electronics for the GEM detector.

A novel approach to the Gas Electron Multiplier (GEM) detector readout is presented. Unlike commonly used methods, based on discriminators[2],[3] and analogue FIFOs[1], the method developed uses simultaneously sampling high speed ADCs and advanced FPGA-based processing logic to estimate the energy of every single photon. Such method is applied to every GEM strip signal. It is especially useful in case of crystal-based spectrometers for soft X-rays, where higher order reflections need to be identified and rejected[5].

Proton spectroscopy of Ni 48, Fe 46, and Cr 44

Results of decay spectroscopy on nuclei in vicinity of the doubly magic 48Ni are presented. The measurements were performed with a Time Projection Chamber with optical readout which records tracks of ions and protons in the gaseous volume. Six decays of 48Ni including four events of two-proton ground-state radioactivity were recorded. An advanced reconstruction procedure yielded the 2p decay energy for 48Ni of Q2p = 1.29(4) MeV. In addition, the energy spectra of \b{eta}-delayed protons emitted in the decays of 44Cr and 46Fe, as well as half-lives and branching ratios were determined. The results were found to be consistent with the previous measurements made with Si detectors. A new proton line in the decay of 44Cr corresponding to the decay energy of 760 keV is reported. The first evidence for the \b{eta}2p decay of 46 Fe, based on one clear event, is shown.

β -delayed proton emission branches in Cr 43

The beta+ decay of very neutron deficient 43Cr has been studied by means of an imaging time projection chamber which allowed recording tracks of charged particles. Events of beta-delayed emission of one-, two-, and three protons were clearly identified. The absolute branching ratios for these channels were determined to be 81(4)%, 7.1(4)%, and 0.08(3)%, respectively. The 43Cr is thus established as the second case in which the beta-3p decay occurs. Although the feeding to the proton-bound states in 43V is expected to be negligible, the large branching ratio of 12(4)% for decays without proton emission is found.

Pi of the Sky—robotic telescope

Pi of the Sky is a system of wide field-of-view robotic telescopes designed for observations of short timescale astrophysical phenomena, especially for prompt optical GRB emission. The apparatus was designed for autonomous operation, follows the predefined observing strategy and adopts it to the actual conditions, monitoring a large part of the sky with time resolution of the order of 1 - 10 seconds and range 12m-13m. Observation strategy and system design was successfully tested with a prototype detector working in 2004-2009 at Las Campanas Observatory, Chile, and moved to San Pedro de Atacama Observatory in March 2011. In October 2010 the first unit of the final Pi of the Sky detector system, with 4 CCD cameras, was successfully installed in the INTA El Arenosillo Test Centre in Spain. Simultaneous observations from locations in Chile and Spain allow a systematic search for optical transients of cosmological origin. Accurate analysis of data arising from a wide-field system like Pi of the Sky is a real challenge because of a number of factors that can influence the measurements. We have developed a set of dedicated algorithms which remove poor quality measurements, improve photometric accuracy and allow us to reach uncertainties as low as 0.015– 0.02 mag. Three more units (12 CCD cameras) are being prepared for installation on a new platform in INTA, aiming at a total coverage of about 6400 square degrees. Status and performance of the detectors is presented.

Pi of the Sky Telescopes in Spain and Chile

Pi of the Sky is a system of robotic telescopes designed for observations of short timescale astrophysical phenomena, e.g. prompt optical GRB emissions. The apparatus is designed to monitor a large fraction of the sky with 12–13 m range and time resolution of the order of 1–10 seconds. In October 2010 the first unit of the new Pi of the Sky detector system was successfully installed in the INTA El Arenosillo Test Centre in Spain. We also moved our prototype detector from Las Campanas Observatory to San Pedro de Atacama Observatory in March 2011. The status and performance of both detectors is presented.

Present status of Pi of the Sky telescopes

In October 2010 Pi of the Sky set up a new system, consisting of 4 cameras installed on a new mount, in El Arenosillo, in southern Spain. It was followed by moving the prototype system from Las Campanas Observatory (central Chile) to San Pedro de Atacama (northern Chile) in March 2011. In this paper our new sites, some details about observational conditions and first results in both observatories are described.