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«The H1-Detector at HERA»

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This is the WWW Version of the H1 detector paper which has been published as internal Report DESY-H1-96-01 March 96 (updated version of Report DESY 93-103). It is based on a version which is published in Nucl. Instr. and Meth.A. 386, 1997, (in two parts: pages) 310 - 347 and 348 - 396).

Information for Use

Each Chapter of the following list is accessible by a ps-file. This file contains tables, however, not the figures. The complete ps file of part 1 [433 k] and part 2 [544 k]are also available.

The figures are accessible for each chapter. Each individual picture is available as gif (click to "Fig. x") with the appropriate figure caption and (especially for printing) as compressed ps_file (click to "ps-file").

The numbering of chapters and figures is done according to the version to be published in Nucl. Instr. and Meth. To ease the retrieval of figures also the fig. nr. of the internal Report DESY H1-96-01 are shown.


Part1: The H1 Detector at HERA

This part contains: General aspects of the H1 detector (magnet, luminosity system, trigger, slow control, data acquisition, off-line data handling) and performance in 1993/94

Goto Part 2 (The three major detector components)

0. Title, Abstract, Authors; Table of Contents, List of Figures and list of Tables

pages 0 to 4 [167 k]

1. Introduction

pages 5 to 6 [119 k]

Fig. 1 (Fig 1.1) ps-file [1.3 M]
HERA Kinematics

2. General Description of the H1 Detector

pages 7 to 12 [145 k]

Fig. 2 (Fig 2.1) ps-file [102 k]
Schematic layout of H1 Detector, showing the H1 reference frame
Fig. 3 (Fig 2.2) ps file [1568 k]
Longitudinal cut through the H1 detector along the beam line
Fig. 4 (Fig 2.3) ps file [782 k]
Front view of the H1 detector with the southern and the northern shells of the iron yoke opened.
Fig. 5 (Fig 2.4) ps file [510 k]
Cross section of the beam pipe in the H1 detector.
Fig. 6 (Fig 2.5) ps file [859 k]
Performance of the HERA storage ring in the first three years of operation.
Fig. 7 (Fig 2.6) ps file [1037 k]
Arrangement of synchrotron masks shielding the H1 from direct synchrotron radiation.

3. Magnet

pages 13 to 15 [121 k]

Fig. 8 (Fig 3.1) ps-file [1037 k]
Main coil field map over the tracking volume.

4. Luminosity system and electron tagger

pages 16 to 18 [126 k]

Fig. 9 (Fig 7.1) ps-file [706 k]
The layout of the luminosity system.
Fig. 10 (Fig 7.2) ps-file [672 k]
e - gamma energy correlation for bremsstrahlung events detected by luminosity calorimeters.
Fig. 11 (Fig 7.3) ps-file [672 k]
Data provided by the luminosity system during the e-p collisions at HERA.

5. Trigger

pages 19 to 30 [184 k]

Fig. 12 (Fig 8.1) ps-file [1292 k]
a) z- vertex reconstruction by building a histogram, which didplays a peak at the true vertex location.
b) Block diagram of the z- vertex trigger.
Fig. 13 (Fig 8.2) ps-file [655 k]
Block diagram of the drift chamber trigger.
Fig. 14 (Fig 8.3) ps-file [825 k]
Block diagram of the liquid argon calorimeter trigger.
Fig. 15 (Fig 8.4) ps-file [612 k]
Cross section through the plane of the liquid argon calorimeter showing the pointing geometry of the trigger big towers.
Fig. 16 (Fig 8.5) ps-file [468 k]
BEMC single electron trigger efficiency for thresholds CL1 and CL2.
Fig. 17 (Fig 8.6) ps-file [689 k]
Principle of track recognition in the forward muon trigger.
Fig. 18 (Fig 8.7) ps-file [493 k]
The frontend response time as a function of the instantaneous input frequency (1/time between consecutive events).

6. Slow control

pages 32 to 33 [113 k]

Fig. 19 (Fig 9.1) ps-file [774 k]
Flow of slow control data within H1.

7. The data acquisition system

pages 33 to 37 [136 k]

Fig. 20 (Fig 10.1) ps-file [808 k]
Overview of the H1 data acquisition system.
Fig. 21 (Fig 10.2) ps-file [723 k]
VMEtaxi fundamentals.
Fig. 22 (Fig 10.3) ps-file [1318 k]
Physical layout of the key features of the H1 data acquisition system.
Fig. 23 (Fig 10.4) ps-file [672 k]
Multi-event buffer units.
Fig. 24 (Fig 10.5) ps-file [867 k]
Full event buffer units.
Fig. 25 (Fig 10.6) ps-file [1420 k]
Physical composition of the central part of the H1 data acquisition system as during the data taking periods of 1993 and 1994.

8. Off-line data handling and simulation

pages 38 to 40 [122 k]

Fig. 26 (Fig 11.1) ps-file [1258 k]
H1 off-line computing environment.
Fig. 27 (Fig 11.2) ps-file [774 k]
Schematic view of the parametrized shower simulation in a coarse geometry.
Fig. 28 (Fig 11.3) ps-file [816 k]
Physics analysis with LOOK.

9. Summary of first operation at HERA

pages 41 to 43 [114 k]

Fig. 29 (Fig 12.1) ps-file [1309 k]
Typical two jet event.
Fig. 30 (Fig 12.2) ps-file [366 k]
Absolute trigger rates recorded in the backward electromagnetic calorimeter in function of cluster energy at different trigger and reconstruction levels.
Fig. 31 (Fig 12.3) ps-file [697 k]
Typical high Q event with both the scattered electron and the hadronic recoil jet observed in the LAr calorimeter.
Fig. 32 (Fig 12.4) ps-file [893 k]
Invariant mass distribution of elastically (top) and inelasticaly (bottom) produced pairs in photoproduction.
Fig. 33 (Fig 12.5) ps-file [842 k]
Signals observed in the central jet chamber.

Figure Captions

pages 44 to 67 [117 k]

References

pages 68 to 74 [130 k]


Part 2: The Tracking, Calorimeter and Muon Detectors of the H1 Experiment

Goto Part 1

0. Title, Abstract, Authors; Table of Contents, List of Figures and List of Tables

pages 0 to 8

1. Introduction

pages 9 to 10 [179 k]

Fig. 1 (Fig 2.1) ps-file [102 k]
Schematic layout of H1 Detector, showing the H1 reference frame.

2. Tracking

pages 11 to 36 [114 k]

Fig. 2 (Fig 4.1) ps-file [850 k]
The H1 tracking system (r - z view).
Fig. 3 (Fig 4.2) ps-file [799 k]
Central tracking system.

2.1 Central Jet Chambers: CJC1 and CJC2

pages 12 to 17 [154 k]

Fig. 4 (Fig 4.3) ps-file [1377 k]
Simulation of a NC event and of a CJC cell.
Fig. 5 (Fig 4.4) ps-file [646 k]
Dependance of the CJC z resolution on the amount of ionisation.
Fig. 6 (Fig 4.5) ps-file [757 k]
Specific ionization verus particle momentum measured in the CJC in HERA runs.

2.2 Central z-chambers

pages 17 to 19 [125 k]

Fig. 7 (Fig 4.6) ps-file [791 k]
Longitudinal and transverse cross-section through a cell of the CIZ.
Fig. 8 (Fig 4.7) ps-file [825 k]
Schematic view of the COZ.

2.3 Forward tracking detector

pages 19 to 23 [133 k]

Fig. 9 (Fig 4.8) ps-file [825 k]
Forward tracker overview.
Fig. 10 (Fig 4.9) ps-file [1148 k]
Details of the forward tracker constuction.

2.4 Drift chamber electronics, readout, and front end data processing

pages 23 to 26 [137 k]

Fig. 11 (Fig 4.10) ps-file [1224 k]
FADC readout system for drift chambers.

2.5 Proportional chambers

pages 27 to 31 [140 k]

Fig. 12 (Fig 4.11) ps-file [689 k]
Longitudinal cross-section and details of the COP.
Fig. 13 (Fig 4.12) ps-file [638 k]
Cross-section throgh the backward proportional chamber.
Fig. 14 (Fig 4.13) ps-file [1003 k]
MWPC front end electronics and read-out systems.

2.6 Gas systems

pages 32 to 34 [124 k]

Fig. 15 (Fig 4.14) ps-file [1071 k]
Layout of the closed ciruit gas systems for the planar drift chambers.

2.7 Scintillators

pages 34 to 35 [85 k]

Fig. 16 (Fig 4.15) ps-file [604 k]
Schematic cross-section of the inner and outer veto wall (left) and the ToF counters.
Fig. 17 (Fig 4.16) ps-file [408 k]
Time distribution of hits in a ToF counter.

3. Calorimetry

page 37 to 52 [202 k]

3.1 The liquid argon (LAr) calorimeter

pages 37 to 46 [161 k]

Fig. 18 (Fig 5.1) ps-file [1547 k]
a) Longitudinal view of calorimeters.
b) Radial view of a LAr calorimeter wheel.
Fig. 19 (Fig 5.2) ps-file [859 k]
Schematic structure of the readout cell:
a) e.m.cell,
b) hadronic cell.
Fig. 20 (Fig 5.3) ps-file [553 k]
Relative stability of the electronic chain over the month.
Fig. 21 (Fig 5.4) ps-file [774 k]
Noise contribution summed over all channels of the LAr calorimeters.
Fig. 22 (Fig 5.5) ps-file [638 k]
Correlation between the true energy lost in front of the calorimeter and its esimation in the reconstruction for simulated low Q DIS.
Fig. 23 (Fig 5.6) ps-file [680 k]
The effective mass of two photons before and after the dead material correction.
Fig. 24 (Fig 5.7) ps-file [706 k]
Performance of the dead material correction for simulated pions at 20 GeV.
Fig. 25 (Fig 5.8 ps-file [544 k]
Reponse across the CB2/CB3 z crack in pion test beam of 30 GeV at CERN.
Fig. 26 (Fig 5.9 ps-file [621 k]
Reconstructed energy of data and MC for electron of 10, 20, 30 and 50 GeV.
Fig. 27 (Fig 5.10 ps-file [842 k]
Energy resolution as function of electron energy for wheels BBE.
Fig. 28 (Fig 5.11 ps-file [650 k]
Energy reconstruction for pions at 80 GeV for wheels CB, FB and IF .
Fig. 29 (Fig 5.12 ps-file [748 k]
Energy reconstruction for pions at 205 GeV for wheel IF with tail catcher.
Fig. 30 (Fig 5.13 ps-file [638 k]
Energy resolution as function of pion energy for wheel IF.
Fig. 31 (Fig 5.14 ps-file [859 k]
Energy/momentum match of electrons generated by cosmic muons measured in the CJC and LAr CB wheels.
Fig. 32 (Fig 5.15 ps-file [680 k]
Transverse momentum balance for both scattered electron and hadronic shower detected in the LAr for data and Monte Carlo .

3.2 The backward electromagnetic calorimeter (BEMC)

pages 46 to 48 [122 k]

Fig. 33 (Fig 5.16) ps-file [714 k]
Transverse view of the BEMC barrel and longitudinal cross-sections of BEMC.
Fig. 34 (Fig 5.17) ps-file [553 k]
Energy spectrum of low Q DIS electrons scattered in the region BEMC stacks.

3.3 The plug calorimeter

pages 48 to 49 [116 k]

Fig. 35 (Fig 5.18) ps-file [774 k]
Cross sectinal view of the PLUG calorimeter.
Fig. 36 (Fig 5.19) ps-file [187 k]
Typicall I/V - and C/V . Characteristics of the PLUG Si-detectors.
Fig. 37 (Fig 5.20) ps-file [1301 k]
PLUG reponse to ep events compared to a MC simulation.

3.4 The tail catcher (TC)

pages 50 to 51 [120 k]

Fig. 38 (Fig 5.21) ps-file [825 k]
Muon spectra summed over a complete module for a) inner towers normalized to 4 planes, and b) outer towers normalized to 5 planes. The curves are fits to a Landau distribution.
Fig. 39 (Fig 5.22) ps-file [757 k]
Ratio of the total transverse hadronic energy - including the corrected TC energy - and the transverse electron versus the energy fraction in the TC, for NC events. The line is a fit to the data.

4. Muon system

page 53 to 58 [139 k]

4.1 Iron instrumentation

pages 53 to 56 [127 k]

Fig. 40 (Fig 6.1) ps-file [663 k]
Structure of LST chambers.
Fig. 41 (Fig 6.2) ps-file [799 k]
Iron instrumentation showing the pointing pad structure of the barrel region.
Fig. 42 (Fig 6.3) ps-file [1369 k]
The local data acquisition system.
Fig. 43 (Fig 6.4) ps-file [570 k]
Efficiency of chamber planes.
Fig. 44 (Fig 6.5) ps-file [655 k]
Wire and strip multiplicity per event.
Fig. 45 (Fig 6.6) ps-file [646 k]
Muon reconstruction efficiency in the barrel region as function of the muon energy (GeV) determined from cosmic muons.

4.2 Forward muon spectrometer

pages 56 to 58 [121 k]

Fig. 46 (Fig 6.7) ps-file [672 k]
a) A schematic view of the forward muon spectrometer and b) the cell structure of a double layer.

Figure Captions

pages 60 to 87 [141 k]

References

pages 88 to 93 [105 k]


Last update by Jochen Buerger (h1webm@dice.desy.de), Mar 3 1997 at 14:07.