OPERA

THE COLLABORATION

- INFN: INFN and Bari University, INFN and Bologna University, INFN Laboratori Nazionali di Frascati, INFN and Naples "Federico II" University, INFN and Padova University, INFN and Rome "La Sapienza" University, INFN and Salerno University,
- Belgium: IIHE (ULB-VUB), Brussels
- CERN, Geneva, Switzerland
- China: IHEP, Beijing; Shandong University, Tsinan (Shantung)
- Croatia: Rudjer Boskovic Institute (IRB), Zagreb,
- France: LAPP and Université de Savoie, Annecy; Laboratoire de l'Accélérateur Linéaire (LAL), IN2P3-CNRS and Université Paris-Sud, Orsay; IPNL, IN2P3-CNRS and Université C. Bernard Lyon I, Villeurbanne; Institut de Recherches Subatomiques, IN2P3-CNRS/ULP BP20, Strasbourg;
- Germany: Humboldt University, Berlin; Märkische Fachhochschule FB Elektrotechnik, Hagen; Hamburg University, Hamburg; Münster University, Müenster; Fachbereich Physik der Universitaet Rostock, Rostock,
- Israel: Israeli group c/o Technion, Haifa
- Japan: Aichi Educational University, Aichi; Toho University, Funabashi; Kobe University, Kobe; Nagoya University, Nagoya; Utsunomiya University, Utsunomiya
- Russia: JINR, Dubna; INR, Moscow; ITEP, Moscow
- Switzerland: Bern University, Bern; Neuchatel University, Neuchatel
- Turkey: METU, Ankara

Laboratory/Beam: Gran Sasso National Laboratory/CNGS

National Responsible: A. Ereditato (Na)

1. GOAL OF THE EXPERIMENT

The goal of OPERA (Oscillation Project with an Emulsion tRacking Apparatus), is a search for nm-nt oscillations with a long baseline t appearance experiment in the CNGS neutrino beam from the CERN SPS to the Gran Sasso Laboratory. The experiment will be able to test the oscillation parameters indicated by the atmospheric neutrino anomaly, as reported by the Super-Kamiokande experiment.

More on the experiment...

2.

Activities during 2001

The Experiment Proposal was submitted to the Scientific Committees in 2000 and the experiment approved by CERN and INFN. In 2001 a Status Report was produced in which the progress in the realization of the experiment was outlined.

The technical design of the experiment progressed as well as the assessment of its expected performance by simulations and test measurements performed on prototype detectors (emulsion bricks and electronic detectors) exposed to particle beams.

In addition to the general properties of the newly developed industrial emulsion films (sensitivity, ageing features, controlled erasing, etc.) we have studied: the hit-brick finding efficiency by electronic trackers, the vertex finding efficiency (by scanning the emulsion films in the brick), the particle ID by measurement in the emulsions and the determination of the momentum by multiple scattering measurement in the lead/film sandwich structure. The collaboration is also evaluating the possible use of additional emulsion films placed downstream of each individual brick (changeable sheets) with the aim of improving the brick finding efficiency and reducing the fired brick scanning time.

Among the three options for the target tracker technology (liquid scintillator tubes, RPCs and solid scintillators) the collaboration decided to proceed with the construction of the baseline option constituted by scintillator strips read out by multianode PMTs. A full scale module was realized and tested. Industrially produced scintillator strips and commercial photodetectors have been tested and their response was found adequate. The conceptual design of the veto system was carried out.

We completed the technical design of the support structure of bricks and electronic detectors (walls) and realized a full scale prototype filled with fake bricks. We are advancing on the automation related to the brick assembly machine (BAM), on the and installation and removal of bricks (a prototype manipulator has been realized), and on the handling of the emulsion films before the run (erasing of background tracks) and after (development).

The technical design of the magnets was completed and the tendering and purchasing procedure for the different components started. A full scale magnet prototype was assembled and its operation tested successfully. The design of the inner detectors (RPCs) was completed and prototypes were ordered and tested in laboratory and in test beams. The technical design of the precision trackers (drift tubes) was carried out and tests made on full scale prototypes.

Another R&D activity concerned the development of next generation automatic scanning devices. The first prototype of the S-UTS system being developed in Japan is operational. It will eventually feature a scanning speed of more than 20 cm2 of emulsion film surface per hour, meeting the OPERA requirements. Another system is being developed in Italy with similar expected features and based on the so-called multi-track approach. The present prototype performance are satisfactory.

We are evaluating in detail all construction and installation procedures in the underground hall in LNGS, as well as the requests in terms of space, infrastructure and manpower.

The following milestones were set by the Italian groups for 2001, all expiring on 31 December 2001:

1) Data analysis of tests on prototypes: fulfilled;

2) Magnet prototype completed with RPCs: the magnet prototype has been realized and tested. RPC detectors should be added in 2002. (70% fulfilled).

3) Advanced design of the support structure: fulfilled; technical designs have been produced for the general support structure and for the wall mechanics.

4) Definition of the conceptual design for automatic systems for brick assembly and movement: fulfilled. Designs exist for the BAM and the manipulator. For the latter a prototype has been realized.

5) Definition of the multi-track system (scanning):80% fulfilled, to be completed during 2002. The main items of the system have been identified (stage, software, readout, etc.) and tests are in progress.

Milestones 2002

Start RPC production for spectrometers | 28-02-2002
Start installation of the first spectrometer | 30-09-2002
Engineering design of the support mechanical structure | 31-12-2002
Definition of the design of the brick assembly machine (BAM) | 31-12-2002
Construction of prototype high speed microscopes for scanning stations | 31-12-2002

3.INFN CONTRIBUTION TO THE EXPERIMENT IN TERMS OF MANPOWER AND FINANCIAL SUPPORT

Manpower:

About 40 researchers from the Italian groups contributed to the OPERA activities in 2001 (nearly 22 FTE). We profited from the technical support from the Sezioni INFN: technical design (LNF, Napoli, Padova), emulsion and brick handling (Bari, Bologna, Napoli, Roma, Salerno), electronic detectors (LNF, Padova), electronics design (Napoli, LNF, Padova). Local support was also given to the R&D activities on automatic scanning (Bari, Bologna, Napoli, Roma, Salerno). A contribution was given by the technical services of the LNGS for setting up the emulsion laboratory at Gran Sasso, the cosmic ray station for emulsion alignment and to perform radioactivity measurements on the site.

About 10 dedicated technicians have been involved (5 FTE) in addition to about 90 man-year from general technical workshops (Sezioni INFN).

Budget for the Year 2002: 3247 kEuro

4. PUBLICATIONS IN REFEREED JOURNALS (Year 2001)

No publications in refereed journals.

5. CONFERENCE TALKS (Year 2001): 5

6. NUMBER OF UNDERGRADUATE AND DOCTORAL THESIS ON THE EXPERIMENT

Concerning the Italian groups:

10 Laurea Thesis in Physics completed or in progress; 3 Doctoral Thesis.

7. LEADERSHIP ROLES IN THE EXPERIMENT

Spokesperson: P. Strolin;

Gran Sasso Technical Coordinator: M. Spinetti;

8.INNOVATIVE INSTRUMENTS

Innovative instrumentation is being developed in two main fields related to the operation of the detector at Gran Sasso and to the analysis of the emulsion films. Specialised industry has been involved.

Automation:

- computer controlled systems for emulsion brick packing and handling;
- automatic devices for high speed and high precision movements (microscope mechanics).

High definition image analysis:

- new generation CCD cameras and CMOS sensors with high frame rate and high image quality;
- new multi-processor frame grabbers for on-line image analysis.

9. COMPETING EXPERIMENTS

Other planned, approved or running long baseline neutrino oscillation experiments with the aim of studying the atmospheric neutrino deficit with terrestrial experiments are:

- Super-Kamiokande in Japan with the K2K beam from KEK;
- MINOS in Minnesota with the NuMI beam from FERMILAB;
- ICARUS at Gran Sasso with the CNGS beam from CERN.

K2K is running and can perform a disappearance search for neutrino oscillations, as well as MINOS, starting from 2003. ICARUS can study nm-nt oscillations with an appearance experiment based on the kinematical selection of the t signal. OPERA will be the only experiment able to directly identify the t decay topology through the detection of its (short) track with the emulsion films. The experiment will start running in 2005.

10.INTERNATIONAL COMMITTEES WHICH HAVE REVIEWED THE EXPERIMENT

The OPERA Letters of Intent and the Experiment Proposal (which can be found on the web: http://opera.web.cern.ch/opera/ )have been reviewed by the CERN Super Proto Synchrotron Committee (SPSC) and by the Gran Sasso Laboratory Scientific Committee (LNGSSC).