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This specification, drawn up by the instrumentation specification board 2, describes the requirements concerning orbit and trajectory measurements in the PS machine. The orbit measurement and the trajectory measurement are both indispensable in order to be able to guarantee the correct beam quality for beams like LHC, the future Grand Sasso beam, the nTOF beam and surely the combined operation of the nTOF beam and the East Area beam.

The PS ring is equipped with 40 position PUs distributed around the ring. These are connected to the CODD system, which performs trajectory measurements of any single bunch, on two consecutive turns, and to 40 Normalisers, which deliver an averaged orbit. CODD uses a beam-synchronous timing system, which tracks a given bunch all through the acceleration cycle, but needs resynchronization after harmonic changes. It measures at injection or at any given C-timing, albeit with no less than 5ms between acquisitions. It is blind during harmonic changes. A Normaliser, using a technique originally developed for radial loop control, produces a slow signal, proportional to the average position of the bunches. At beam injection a settling time of 1.5ms is needed; then it follows orbit changes with a 200us time constant. Thus, it will not show rapid position changes, such as betatron oscillations. It does not require accurate timing. In the PS installation, the Normaliser outputs are simply sampled at 1ms intervals. CODD affords measurements on single bunches right from injection, but needs a complicated timing system and delivers results with mediocre resolution. The Normaliser, on the other hand, has simple timing, but produces the average orbit over the whole beam over a few hundred microseconds, thus missing the injection event. The averaging lends it a better resolution than CODD, though not by as much as could have been expected, based on its time constants. The aim of this document is to compare both systems and show the superiority of the Normaliser for closed-orbit measurements.

Damping Rings for Linear Colliders have to produce very small normalised emittances at a high repetition rate. A previous paper presented analytical expressions for the equilibrium emittance of an arc cell as a function of the deflection angle per dipole. In addition, an expression for the lattice parameters providing the minimum emittance, and a strategy to stay close to this, were proposed. This analytical approach is extended to the detailed design of Damping Rings, taking into account the straight sections and the damping wigglers. Complete rings, including wiggler and injection insections, were modelled with the MAD [1] program, and their performance was found to be in good agreement with the analytical calculation. With such an approach it is shown that a Damping Ring corresponding to the Compact Linear Collider (CLIC) parameters at 0.5 and 1 TeV centre-of-mass energy, and tunable for two different sets of emittance and injection repetition rate, can be designed using the same ring layout.

The CLIC study of a high energy (0.5 - 5 TeV), high luminosity (1034 - 1035 cm-2 sec-1) e± linear collider is presented. Beam acceleration using high frequency (30 GHz) normal-conducting structures operating at high accelerating fields (150 MV/m) significantly reduces the length and, in consequence, the cost of the linac. Based on new beam and linac parameters derived from a recently developed set of general scaling laws for linear colliders, the beam stability is shown to be similar to lower frequency designs in spite of the strong wake-field dependency on frequency. A new cost-effective and efficient drive beam generation scheme for RF power production by the so-called "Two Beam Acceleration (TBA)" method is described. It uses a thermionic gun and a fully-loaded normal-conducting linac operating at low frequency (937 MHz) to generate and accelerate the drive beam bunches, and RF multiplication by funnelling in compressor rings to produce the desired bunch structure. Recent 30 GHz hardware developments and results from the CLIC Test Facility (CTF), assessing the feasibility of the scheme, are described.

The progress of the Compact LInear Collider (CLIC) study of a multi-TeV (0.5 - 5 TeV) high-luminosity (5'1033 to 1.5'1035 cm-2 sec-1) e± linear collider based on Two-Beam Acceleration (TBA) is presented. The length and, in consequence, the cost of the overall complex is reduced by the use of high accelerating fields (150 MV/m), which are generated by specially damped 30 GHz normal-conducting accelerating structures. The large amount of RF power (400 MW/m) required to generate these high fields is provided by a novel RF power generating scheme which is potentially both cost and power efficient. After summarising the progress made in the developments of 30 GHz components and the performance obtained in the present phase of the CLIC Test Facility (CTF2), the design of a new test facility (CTF3), which will demonstrate the feasibility of the RF power generating scheme, is described

The CLIC study of a high energy (0.5 - 5 TeV), high luminosity (10^34 - 10^35 cm^-2 sec^-1) e± linear collider is presented. Beam acceleration using high frequency (30 GHz) normal-conducting structure s operating at high accelerating fields (100 to 200 MV/m) significantly reduces the length and, in consequence the cost of the linac. Based on new beam and linac parameters derived from a recently dev eloped set of general scaling laws for linear colliders, the beam stability is shown to be similar to lower frequency designs in spite of the strong wake-field dependency on frequency. A new cost effe ctive and very efficient drive beam generation scheme for RF power production by the so-called "Two Beam Acceleration (TBA)" method is described. It uses a conventional thermionic gun and a fully-load ed normal-conducting linac operating at low frequency (937 MHz) to generate and accelerate the drive beam bunches and RF multiplication by funneling in compressor rings to produce the desired bunch st ructure. Recent 30 GHz hardware developments and results from the CLIC Test Facility (CTF) assessing the feasibility of the scheme are described.

The precise measurement of the transverse tunes and their spectra is a basic demand in accelerator commissioning. It provides a simple access to lattice characterisation and validation of the optical model. This contribution describes recent improvements of the tune monitor system at the Accelerator Test Facility Damping Ring (ATF-DR) and the performance achieved. We present preliminary measurement results of beta functions, chromaticity, and dispersion on a relaxed optics with 90 degree horizontal phase advance per cell and compare these with the theoretical predictions.