CERN's ISOLDE, an acronym for Isotope Separator On Line, went into operation again in 1992, after a major upgrading that has placed the facility in a new building complex fed by a 1 GeV proton beam from the injector synchrotron, called the PS Booster (PSB). Hence, ISOLDE is now firmly integrated into the accelerator architecture of CERN. In the following sections the ISOLDE facility will be presented (see also poster). As an introduction you may look at some historic dates of ISOLDE:

The proton injector for ISOLDE, the PS Booster, is a stack of four small synchrotrons pre-accelerating protons, delivered by a Linac, to 1 GeV before injection into the CERN Proton Synchrotron (PS). PS in turn supplies particles to all CERN's high-energy machines. The PSB gives one pulse of 3.2*10¹³ protons every 1.2 seconds. Up to half of the pulses in the 12 pulses long super cycle to the PS is brought to bombard the ISOLDE target. This gives an equivalent of about 2 microA dc beam. The transfer of ISOLDE from the 600 MeV dc proton beam at the CERN SC to the time structure, with a short high density proton pulse at low repetition rate, increased the release time of the produced radioactivity from the target. This increased predominantly the production of very short-lived species and makes the ISOLDE beam bunched. In addition it allows "background free" experiments between the pulses because the neutrons, which are the main sources of background, die out in the first 100 ms after the beam burst. The target technique developed at the SC ISOLDE is, in most cases, directly applicable with the new beam. As shown in the ISOLDE layout the protons from the PSB are delivered to the ISOLDE target zones via an underground transfer line, which serves two different isotope separators, one with its target position situated in a straight extension of the beam line and a second one after a bend of 400 mrad. The bending magnets are laminated with the possibility of running the two ISOLDE separators parallel in a time-shared mode. The two separators are arranged such that a beam from either machine can be fed into a common beam distribution system to which almost all of the experiments in the 700 m² experimental hall are connected.  
 
ISOLDE's target area has always been one corner of CERN where special attention to safety was necessary. Not only are and were radiation levels high but there is a constant possibility of a local release of a large amount of volatile radioactivity from the target systems. for this reason, great attention has been paid to safety in the new design. The most important step forward is that the main experimental area, to which the physicists have access, is completely separated from the radioactive handling bay, to which access is through a special entrance.
The radioactive handling bay house laboratories equipped with manipulators and fume hoods suitable for post-mortems and repairs of irradiated target-ion-source systems and gives access to the beam tunnel and the two target areas with their high-voltage zone. The handling of the targets is done by two industrial robots, similar to those used in the automobile industry. The robots can couple a target to the vacuum of the front end of the separator without human intervention, and can later bring the used  and highly radioactive target to storage shelves placed in the walls of the robot galleries. The whole region around the target is shielded with steel and concrete blocks and has been buried under 8 m of earth.
An important feature is that the ventilation system is designed to ensure that possible accidental release of airborne radioactive contamination is kept within the confined area. The system also ensures that the activated air is kept long enough for the contamination to decay. Exhaust gas from the vacuum pumps of the separators is stored to decay in steel tanks before being released through a series of filters.
 

ISOLDE uses two different separators, the first of which was put into operation in Summer 1992, called the General Purpose Separator (GPS). It is designed to allow three different beams within a certain mass range to be selected and delivered simultaneously into the experimental hall via three different beam lines (central mass, low mass and high mass beam line). The second separator, which has meanwhile also been installed, is specially constructed as a High Resolution Separator (HRS) and can only deliver one mass at a time to the experimental hall.

In order to make the best use of the space available in the experimental hall, a central beam line is constructed to allow ions from either of the two separators to be used. The beams are merged together with cylinder shaped electrostatic deflectors, combined with a final parallel plate condenser used as the final beam-kicker, steering the beam into the central beam line. The beam distribution system from the central beam line is illustrated in the ISOLDE layout.

One major problem with the pulsed beam is the load on the acceleration voltage from the intense ionisation in the air, both in front of and behind the ISOLDE target and also in the surrounding air due to high energy particles. The instantaneous beam current is approaching 2 A. If the separator and target and ion-source is kept at a constant high-voltage, as is conventionally one, any normal supply might break down during beam impact. A pulsed power supply was therefore constructed to bring down the 60 kV high voltage to zero 35 micro seconds before beam impact. The voltage is the restored to its normal value again after ~6 ms.

The control systems of the isotope separators and beam lines are based on personal computers (Intel 80386 or higher microprocessor running under MS-DOS or Microsoft Windows). Network wide distributed front end computers, which access the hardware for controls and measurements, are controlled by PC-consoles via a local area network with a PC file server used as database.
 

For a complete description see the laboratory portrait by B. Jonson, H.L. Ravn and G. Walter in: Nuclear Physics News, Vol. 3, No. 2 (1993)