Howard Gordon

Performance of a liquid argon electromagnetic calorimeter with an “accordion” geometry

Abstract The first prototype of a lead—liquid-argon e.m. calorimeter with accordion-shaped absorber and electrode plates has been built and tested with electron and muon beams at the CERN SPS. This novel geometry combines good granularity with high readout speed and minimal dead space. For a response peaking time of 140 ns, an energy resolution of 10%/ E[ GeV ] and a space resolution of 4.4 mm/ E[ GeV ] with a 2.7 cm cell size have been achieved for electrons. The position accuracy for muons is better than 2 mm.

A test of transition radiation detectors for a colliding beam experiment

Abstract We have tested transition radiation detectors (TRDs) to separate electrons from pions in the momentum range between 2.0 GeV/c and 7.5 GeV/c. The radiator materials used in this experiment were polypropylene (CH2) fibers and lithium (Li) foils. A Xe filled longitudinal drift chamber of 3 cm depth was used for detecting transition radiation photons. We compared the methods of truncated mean of the total charge measurements and of maximum likelihood as well as cluster counting methods. We obtained 2% electron/pion separation for the CH2 fibers in the configuration of four modules with total length of 32 cm for a typical geometry of a collider experiment.

A study of exclusive central hadron production at the ISR as a search for gluonium states

Abstract We present first results from a study of the exclusive reaction pp→pπ + π − p at √s=63 GeV with π + and π − produced in the central region. This reaction has been suggested as a method of searching for gluonium states. The π + π − mass distribution shows rapid order of magnitude decreases in cross section at both 1000 MeV/ c 2 and 1500 MeV/ c 2 . Further structure is observed above 2000 MeV/ c 2 .

Performance of a liquid argon Accordion calorimeter with fast readout

Abstract A prototype lead-liquid-argon electromagnetic calorimeter with parallel plates and Accordion geometry has been equipped with high speed readout electronics and tested with electron and muon beams at the CERN SPS. For a response peaking time of about 35 ns, fast enough for operation at the future hadron colliders, the energy resolution for electrons is 9.6%/√E[GeV] with a local constant term of 0.3% and a noise contribution of 0.33 E[ GeV ] . The spatial accuracy achieved with a detector granularity of 2.7 cm is 3.7 mm E[ GeV ] and the angular resolution 12 mrad at 60 GeV.

Bose-Einstein correlations between kaons

Abstract Bose-Einstein correlations between identical charged kaons are observed in αα, pp, and p p collisions at the CERN Intersecting Storage Rings. The average radial extension of the K-enitting region is found to be (2.4±0.9) fm.

Performance of a liquid argon preshower detector integrated with an Accordion calorimeter

Abstract A prototype liquid argon preshower detector with a strip granularity of 2.5 mm has been tested at the CERN SPS in front of a liquid argon Accordion calorimeter. For charged tracks a signal-to-noise ratio of 9.4 and a space resolution of 340 μm were measured; the rejection power against overlapping photons produced in the decay of 50 GeV π 0 s is larger than 3; the precision on

New Ideas and Developments in Calorimetry

The challenges for calorimeter performance in the next decade are reviewed. Some new ideas for calorimeters are described: (1) the test of a parallel plate calorimeter; (2) the use of vacuum photodiodes for calorimeters operating in a magnetic field; (3) the attempt to build high pressure gas sealed tubes as ion chambers in hadron calorimeters; (4) the progress in the attempt to mold plastic loaded with heavy metal for the inert material in gas calorimeters; (5) the use of the limited streamer mode in calorimeters.