Chris Damerell

First measurement of efficiency and precision of CCD detectors for high energy physics

Abstract It has been known for some time that a 2-dimensional charge-coupled device (CCD) might be used for detecting high energy particles with high precision and excellent 2-track resolution. Such detectors could be used to distinguish between prompt tracks and decay products in events producing short-lived particles (heavy leptons, charm, beauty etc.). We now present results in which (for the first time) a telescope of CCD detectors has been operated in a beam of high energy particles. The main results are that even these early detectors have excellent performance characteristics, namely efficiency for track detection of 98±2% per plane, spatial resolution of 4.3 μm and 6.1 μm in two orthogonal directions and 2-track resolution of 40 μm in space.

Charge-coupled devices for particle detection with high spatial resolution

It is expected that the 1980s will see an intensive study of particles with higher flavours (charm, beauty, etc). There is consequently interest in detectors with good spatial resolution which can distinguish between tracks emerging from the primary vertex and those from secondary vertices due to the decay of these short lived particles. In this paper, we consider the possible application of a thin microelectronic device (the charge-coupled device) for this purpose. We conclude that a modest development of existing CCDs could yield a detector with the following characteristics: a) 2-dimensional spatial measurement in orthogonal directions with precision ~ 3 µm. b) 2-track resolution of ~ 60 µm, with no confusion from tracks which overlap in only one projection. c) time resolution ~ 500 nsec. d) readout time ~ 4 msec. e) radiation hardness ~ 3 × 105 rads, equivalent to 1 year of operation in a typical hadron beam of 106 particles per burst.

High statistics inclusive ϕ meson production at SPS energies

AbstractInclusive ϕ meson production has been measured for 100 GeV/c and 200 GeV/c incident π−,

Use of Charge-Coupled Devices as High Precision Detectors

\bar p

Inclusive ϕ meson production, the parton fusion model and strange quark structure functions

andK−, and for 120 GeV/c and 200 GeV/c incident π+,p andK+, using a Be target. A total of 630,000 ϕ mesons has been recorded in the kinematic range 0<xF<0.4. Presented are the differential cross sectionsdσ/dxF anddσ/dpT2. The longitudinal momentum distributions show that the strange valence quarks of the incidentK mesons play an important role in ϕ meson production, even at smallxF. The decay angular distribution of the ϕ meson is evaluated in the Gottfried-Jackson frame and is expressed in the elements of the density matrix. There is a small but significant cos2θGJ dependence for smallpT, which decreases for increasingpT.

A study of the line reversed hypercharge exchange reactions π+p → K+Σ+(1385) and K−p → π−Σ+(1385) at 10 GeV/c

Results of detailed simulations of the charge transfer inefficiency of a prototype serial readout CCD chip are reported. The effect of radiation damage on the chip operating in a particle detector at high frequency at a future accelerator is studied, specifically the creation of two electron trap levels, 0.17 eV and 0.44 eV below the bottom of the conduction band. Good agreement is found between simulations using the ISE-TCAD DESSIS program and an analytical model for the former level but not for the latter. Optimum operation is predicted to be at about 250 K where the effects of the traps is minimal; this being approximately independent of readout frequency in the range 7-50 MHz. This work has been carried out within the Linear Collider Flavour Identification (LCFI) collaboration in the context of the International Linear Collider (ILC) project.

Radiation Hardness of CCD Vertex Detectors for the ILC

We describe here the readout system and performance for the two charge-coupled devices being used in the NA32 charm production experiment on the SPS at CERN by the ACCMOR Collaboration.

An experimental test of exchange degeneracy in the hyperchange exchange reactions π+p→K+Σ+and K−→π−Σ+

Abstract For the first time, the reactions π+p→K+∑+ and K−p→π−∑+ have been studied in the same apparatus. This has been done at an adequately high momentum (10.1 GeV/c) to allow a check of the prediction of exchange degeneracy, that the differential cross sections should be converging at high energy. We have measured the cross section for momentum transfers t between tmin and t = −0.3 (GeV/c)2. We find that for both reactions the differential cross section shows an exponential fall, with no deviations right in to t =tmin (where some other experiments have shown a dip in the cross section). Furthermore, we find the magnitude of the differential cross sections to be closely similar at t = 0, with a ratio R= ( d σ d t) t=0 ( K − p →π − ∑ + ) ( d σ d t) t=0 (π + p → K + ∑ + However, the slope for the positive reaction is about 19% steeper than that for the negative reaction.