The Argonne Tandem-Linac Accelerator System (ATLAS) is a heavy-ion accelerator facility designed for use in basic research and especially for nuclear-physics experiments with low-energy heavy-ion beams. The accelerator consists of two injectors (a 9-MV tandem electrostatic injector and a superconducting injector linac) followed by a superconducting linear accelerator. ATLAS, which is operated by the ANL Physics Division, is a designated National User Facility.
Experiments at ATLAS are performed by ANL staff and by outside users. They are assisted by members of the Physics Division Technical Support Group as needed. The activities of ANL personnel are covered by the Physics Division Conduct of Operations Manual. Additional aspects which arise from the fact that ATLAS is a dedicated National User Facility are covered in this document.
It is the goal of the Physics Division to have all experiments at ATLAS performed safely under conditions which are optimal for the efficient and cost-effective conduct of research of the highest quality. In particular the radiation exposures should be kept as low as reasonably achievable (ALARA).
The purpose of this document is to provide an outline of the basic operating and safety procedures relevant to performing an experiment at ATLAS or for developing new experimental equipment. A more detailed description of the relevant procedures can be found in the supporting documents given below:
Copies of these documents are kept in the ATLAS control room or in the office of the Physics Division Safety Coordinator.
There are presently 8 experimental stations which are in use for experiments with beams from ATLAS. For each station a "System Specialist" has been assigned who has operational responsibility for this station. The current list of the experimental stations and the assigned "System Specialists" (including alternates) is given below. The location of the stations is shown in Fig. 1.
| Apparatus | Location (area) | System Specialist | Alternate |
|---|---|---|---|
| BGO Array | III | R.V.F. Janssens | T.L. Khoo |
| Scattering Chambers | II/III | D.J. Hofman | A.H. Wuosmaa |
| Magnetic Spectrographs | II/III | K.E. Rehm | D.J. Hofman |
| Fragment Mass Analyzer | IV | C.N. Davids | B.B. Back |
| APEX | IV | A.H. Wuosmaa | R.R. Betts |
| Atomic Physics Beamline | III | R.W. Dunford | E. Kanter |
| General Purpose Beamlines | II/III | D.J. Hofman | B.B. Back |
A list of these System Specialists and of support personnel responsible for various technical subsystems (computers, cooling water, etc.) including phone numbers is posted in the ATLAS data room.
The stations are described in more detail in previous sections of the ATLAS Users Handbook. All have undergone safety reviews by appropriate ad hoc safety committees.
It is the responsibility of the System Specialists to see to it that the equipment is kept in safe working condition and is upgraded when necessary. The System Specialist explains to other users who want to use the apparatus possible hazards and other critical issues which might occur during the operation of the experimental equipment. He is also responsible for performing or supervising necessary changes in the equipment as well as for all required safety interlock tests which must be performed and documented.
Installation of new experimental equipment and major changes in each apparatus which could result in a possible safety hazard must be discussed with the Physics Division Safety Coordinator who determines whether additional safety reviews are necessary before the equipment can be used for experiments.
Before an experiment can be performed with beams from the ATLAS accelerator, the proposal for this experiment is reviewed by a Program Advisory Committee which meets two or three times a year. Each proposal gives the names of a spokesperson and an alternate which act as contacts during the approval process and the experiment.
For each experiment an experimental fact-sheet must be filled out by the spokesperson or his/her alternate, specifying beam species, beam energy range, maximum beam currents and other parameters relevant for operation of the accelerator. Potential safety hazards, such as the use of flammable gases, radioactive sources, etc. must be specified on this form. This fact sheet is reviewed by the Scientific Director of ATLAS, the ATLAS Operations Manager and by the Physics Division Safety Coordinator, who confirm with their signature that the appropriate requirements have been met.
Following approval, beamtime can be scheduled. This is done in close coordination between the experimentalists, the beamtime coordinator and the ATLAS operations manager. The proposed schedule is discussed in an open scheduling meeting which is typically held every two months.
It is the responsibility of the spokesperson for an ATLAS experiment to ensure that all collaborators follow accepted safety practices and the rules outlined in the relevant manuals throughout the course of the experiment. The spokesperson shall also consult with the User Liaison Physicist and with the System Specialist for the experimental station he/she intends to use in order to learn about operational details and safety related matters which are relevant for the experiment. The spokesperson shall see to it that relevant information is transmitted to the collaborators involved in the experiment and that changes to the device are made only by persons who have been properly trained.
The training program for all persons working at ATLAS is outlined in Refs. 6,7,9,10. Argonne personnel involved in experiments at ATLAS are required to have documented training in general safety, radiation, and electrical safety. A description of the ATLAS Radiation Interlock System (ARIS) is also part of the training program.
Training of outside users of ATLAS is the responsibility of the User Liaison Physicist. This training consists of instructions concerning ANL and ATLAS safety requirements and procedures.
In addition the System Specialist should give a short introduction into the use and operation of his experimental apparatus.
Good communication between the experimentalists, the User Liaison Physicist, the System Specialist, the operators, and the support personnel is important for both emergency communication and for carrying out a successful experiment.
Any condition which may be hazardous or may lead to a violation of safety standards must be promptly reported.
The emergency procedures are described in detail in Appendix 2 ofthe ATLAS User Handbook. Severe problems which occur with the experimental equipment during the course of the experiment should be immediately reported to the System Specialist.
In some cases it will be necessary that the experimenter assists the Chief Shift Operator (CSO) in certain tasks which require a safety backup during shifts when only one operator is present.
The shift overlap in an experiment should be used to give the new person who will be in charge of running the experiment an accurate picture of the overall status of the apparatus, including possible safety-related problems which occurred during the previous shifts.
Abnormal events which might have safety implications and failures of critical components must be brought to the attention of the System Specialist who decides if this incident should be reported to the Physics Division Safety Coordinator. The safety coordinator ensures that the incident is properly documented.
A log of the individual experiments is maintained in research notebooks which are kept by the individual experimentalists.
Operating procedures and the relevant safety documents for the different experimental stations are kept in special folders in the ATLAS data room, in the Physics Division Safety Coordinator's office, and in the User Liaison's office.
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