HOW WE DO BUSINESS AT DESY
M.Bieler, DESY, Hamburg, Germany
Abstract
DESY is one of the larger accelerator laboratories in theworld with three linacs, two synchrotrons and fife storagerings. All these machines are operated from one control
room. The operators at DESY are recruited from thetechnical support groups and are doing shifts for roughly
a third of their monthly work time.
Advantages and disadvantages of this unusual model
will be described in this paper.

1 DESYDESY (Deutsches Elektronen Synchrotron) inHamburg, Germany, was founded in 1959. Today tendifferent accelerators are operated at DESY: Linac 2(450MeV electrons or positrons) with the positron
intensity accumulator PIA (29m circumference), Linac 3(50MeV H¯ ), DESY 2 (8GeV e+/e- synchrotron, 239mcircumference), DESY 3 (7GeV proton synchrotron,317m circumference), DORIS 3 (4.5GeV synchrotron
radiation source, 289m circumference), PETRA 2(booster for 12GeV e+/e- or 40GeV protons, 2304m
circumference), HERA (collider, 920GeV protons against
27.5GeV e+/e-, two separated rings of 6336mcircumference each) and TTF-FEL, a free electron laser
based on the TESLA test facility TTF, a superconducting
1GeV linac. Figure 1 shows how the different accelerators
at DESY are connected.

Figure 1: Accelerators at DESY.

2 HERAHERA (Hadron Electron Ring Accelerator) is anelectron proton collider for high energy physics. Twoaccelerator rings are built in one tunnel of 6.3km
circumference: The proton ring with superconducting
magnets reaches an energy of 920GeV with a beam
current of 100mA, distributed in 180 bunches. The
normalconducting electron ring reaches 27.5GeV with abeam current of up to 50mA in 189 bunches. Two of thefour experiments at HERA (ZEUS and H1) use colliding
beams to probe the structure of the proton, whereas theHERA-B detector uses a wire target in the halo of theproton beam for fixed target physics. The fourthexperiment, HERMES, uses a polarized gas target and thepolarized electron beam to investigate the spin structureof the proton.

3 ACCELERATOR OPERATIONS
The accelerators at DESY are operated 24 hours per day,
7 days per week, 8-11 month per year. All accelerators areoperated from one central accelerator control room by thesame shift crew. The crew consists of the shift leader (anexperienced operator, responsible for operations andsafety), three operators (engineers or technicians), twomembers of the power supply group and one accelerator
physicist. In addition there are one operator and one or
two physicists working on the TTF-FEL test accelerator.
This crew operates ten very different accelerators with a
total length of approximately 16km.
Apart from the accelerator control room there are thecryogenics control room, the technical emergency service(fire and first aid), the main gate and the control rooms of
the four HERA experiments manned 24 hours per day.
The crew for the accelerator control room is recruitedfrom many different groups of DESY’s machine
department. 61 people from 20 different groups do parttime shift work. Their working contract contains theobligation to do 77 shifts per year, equally distributed
over day and night, weekdays and weekends. These shifts
are done in 11 blocks of 7 shifts per block with twoworking days off after the end of each shift block. For theindividual operator this means that he will work in hisoffice for about three weeks, go on shift for one week,back in the office for about three weeks, back on shift foranother week and so on. As the operators do not work in
fixed teams during their shifts, the time between two shift
blocks can be individually adjusted to the work scheduleand vacation plans of each operator. On average every
operator does shift work for about 30% of his monthly
work time.
During each shift block there is a forward rotationfrom early shift (7am to 3pm) to late shift (3pm to 11pm)

to night shift (11pm to 7am). This rotation assures thatevery operator begins a shift block after a longer break ofoffice work or vacation on an early shift with a crowded
control room and plenty of people around to explain
recent changes in machine operation.

4 OPERATOR TRAINING
The only regular operator training is a one hour weekly
meeting, where background information about accelerator
physics issues are given, recent hardware and softwarechanges are announced and news and current problems
are discussed. Due to their shift cycle only about 2/3 ofthe operators can attend that meeting.
Once per year, usually during the shutdown, there is a
one week seminar held outside DESY where the progressof the last year and the plans for the coming year arediscussed. The meeting is attended by the accelerator
physicists, the shift leaders and some operators, if timeand budget allows.
The most important part of the operator training is thetraining on the job. New operators do several shift blocks
as trainees before they become regular members of theshift crew. As there are no fixed shift crews, the trainees
work with many different shift leaders and operators
during their trainee time. Depending on their curiosity,
this gives them the ability to learn from experts on manydifferent subjects.

5 MAINTENANCE
Once per month HERA operation is interrupted for aservice day. During 8 hours access to the tunnel there istime for preventive maintenance and for a lot of smaller
repairs, which have piled up during the previous month.
The experiments get 16 hours access to their detectors,
while the tunnel is closed after 8 hours to allow forcomponent tests in the remaining time.
If an accelerator component breaks unexpectedly
during operation, the shift crew is able to respond quickly.
All power supply failures are handled by the shift crew
and the mixture of people from different groups on shift
helps to solve almost all other problems without external
help. However, several groups have people on call(quench protection, vacuum, RF, superconducting cavities,
cooling water, power distribution), who can give advice
on the phone, check their systems from their computers athome or come to DESY and help to solve the problem.
Although most shift crews take pride in solving problems
themselves, the shift leaders do not hesitate to call evenpeople who are not ‘on call’ to solve severe problems andget the machines running again.

DESY. The logbook contains both texts and pictures, andevery window of a console application in the control
room can easily be printed into the logbook through an
additional printer queue. The logbook contains a searchengine.
In addition to this electronic logbook, there is a hand
written logbook for radiation safety issues (temporaryaccess,…).
The information flow from shift to shift is organizedthrough a 15 minute meeting at every shift change, wherethe shift leader reports about the last 24 hours andespecially about the progress during his shift. This
meeting takes place at a big table in the accelerator
control room and (during daytime) is attended by manypeople.
Every workday at 8:30am there is an additional
meeting in which the shift leader reports about alltechnical failures in the last 24 hours. This meeting isattended by representatives of all technical support groups.

7 THE CONTROL ROOM
All accelerators at DESY are operated from the sameaccelerator control room by the same shift crew.
Nevertheless there are different consoles for the different
accelerators. This is necessary due to specific hardware
for specific machines and it helps to minimize thedisturbance during machine studies. The use of one big
room makes the communication between the machineseasier, which is important as different machines are using
the same preaccelerators.
Due to the separation of the control room into different
areas for the different machines, the control room has tobe rather big (11m x 38m = 418m²) and has to have agreat number of console screens (152 screens in total).
Figure 2 shows the layout of the accelerator control
room and the areas used for the different machines.

8 THE CONTROL SYSTEM [2]The HERA control system has three system layers: The
console layer (Windows NT), the middle layer and thedevice sever layer. For communication the data exchange
protocol
TINE(Threefold-Integrated
NetworkEnvironment) is used. It provides threefold integration:
Multi platform (UNIX systems (Solaris, Linux, HP-UX,SGI, OSF), DOS, Win16, Win32, ALPHA-VMS, VAXVMS, VxWorks), multi protocol (IP, IPX) and multiarchitecture (client - server, publisher - subscriber,producer - consumer model). For the console layer theGraphical Application Programmers Interface ACOP
(Accelerator Component Oriented Programming) is used.

6 INFORMATION FLOW

9 SPECIAL CHALLANGESThe main source of information about the operation of
HERA is the electronic logbook [1]. The logbook is a
DESY product and was originally designed for aninternational collaboration (TESLA, TTF). It uses JAVA,
is web based and can be read from every computer inside

The challenge for operators at DESY is the operation often very different machines like an electron linac, a H¯linac, an electron synchrotron, a proton synchrotron, asynchrotron radiation source and an electron proton
collider at the same time. The most difficult machine isHERA as a collider with very much different energies, asuperconducting proton machine with an energy gain of23 and an electron machine with several kilowatts ofsynchrotron radiation that have to be guided through theinteraction region without hitting the very sensitive
detectors.

POWER

TTF

HERA

10 REFERENCES[1] http://ttfinfo.desy.de/doocs/elogbook/logbook.html[2] R. Bacher, “Status of the DESY Accelerator ControlSystems,” PCaPAC2000, Hamburg, October 2000.

Vacuum

LINAC2DESY2PETRA

Figure 2: Layout of the DESY accelerator control room.

LINAC3

DESY3DORISInterlock