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The Relativistic Heavy Ion Collider Rhic at Brookhaven*
| Content Provider | Semantic Scholar |
|---|---|
| Author | Ozaki, S. |
| Abstract | The progress in the status of the RHIC project and R&D for the project is presented. Also presented are the salient design features of the RHIC collider which make it unique as a dedicated heavy ion physics machine. Introduction The Relativistic Heavy Ion Collider (RHIC) project at Brookhaven National Laboratory (BNL) has made significant progress this past year. With a well-advanced accelerator design and superconducting magnet R&D, RHIC is ready for construction. An iniliatian uf the RHIC construction was included in the Presidential budget proposal to Congress for FY 1991. Needless to say, this budget proposal is based on the continued support of the nuclear physics community as exemplified by the conclusion of the NSAC: Long Range Plan Working Group, urging an immediate start of RHIC construrtion Two DOE review committees have also concurrrd with that, conclusion. With Congressional approval, construction of the collider can be started in the fall of 1990, with a goal of performing a colliding beam experiment in the spring of 1997. This budget pr[~~:osaI includes a total rsrimated construction cost of $397 M ulcludmg $90 to 100 M for the imtial complement of major detectors. The funding will be distributed over 6 years, with the following profile: FE’ 1991 1992 1993 1994 1995 1996 $15M $50hl $t;OM $90M $90M $72M In addition, the project will continue to receive funding for accelerator and detector R&D at thr level of about, $7 M through FY 1994, and envisages pre-operation funding starting in FY 1995. The “RHIC Project” organization was established as a new entity withitl the Laboratory at the beginning ofFY 1990 to manage the collider and detector construction. Under this project organizat,ion, iz number of task forces are finalizing the details of the accelerator design and preparing for the industrial production of the standard superconducting magnets. The preparation for the RHIC construction has been directed mainly at two technical areas. The first is to generate a viable accelerator design and to solv e accelerator physics questions so that a reliable performance estimate can be made. After intensive studies during the past several years, and with a number of reviews and workshops which evaluated and suggested some improvet~lents, we believe that we have a definitive machine design on hand. Major expected performances and parameters of the RHIC colhder are given in Tables 1 and 2, respectively. The second area is to develop a suitable design of superconducting magnets which matches the requirements from the machine design Although the modest magnetic field strength required for this accelerator allows the magnet design to be simple and less demanding, a careful development was necessary to prove its mass producibility. “Work performed under the auspices of the U.S. Dept. of Energy. **Presented by H. Hahn. Utilizing the existing 3.8 km tunnel and 4 experimental halls which were built for the CBA project (-95% complete), the series of accelerators, from the Tandem Van de Graaff to the AGS (which are in operation), have lowered the cost of the project considerably. The Booster Synchrotron, which will become operational in 1991, will provide a capability for ions as heavy &s gold. In addition, on-going experimental programs with heavy ion beams at the AGS will provide the scientific infrastructure for the effective execution nf the physics program at RHIC. R.HIC Acclerator ConAgnration The RHIC plan calls for the construction of two intersecting storage rings which are capable of accelerating, storing, and colliding ions as heavy as gold at the beam energy of 30-100 GeV/u. The overall accelerator configuration of the RHIC facility is shown in Fig 1. The existing accelerator complex which consists of the Tandem Van de Graaff, Heavy Ion Transfer Line, the Alternating Gradient Synchrotron (AGS), and the new Booster Synchrotron will be used as the injector. Taking the gold ion as an example, negative ion beams from a pulsed sputter ion source (200 /IA, >120 psec, Q = -1) are accelerated by the first stage of the Tandem Van de Graaff, stripped of atomic electrons to Q w +14 by a foil at the high voltage terminal, and accelerated by the second stage to -1 MeV/u. The beams are then transported through a 540 m-long transfer line to the Booster without further stripping of atomic electrons. A test performed for the gold beam indicated that ~2 x 10” gold ions can be delivered to the Booster in 120 psec. After multi-turn injection, beams are grouped into 3 bunches and accelerated to 72 MeV/u. A foil at the Booster exit strips all atomic electrons except for two tightly bound K-shell electrons. The AGS, with its improved vacuum, can accelerate 3 bunches of Q = +77 gold ions to 10.4 GeV/u with only a few percent loss. Ions are fully stripped at the exit of the AGS and injected into the RHIC storage rings. Beam stacking is done in box-car fashion by repeating this acceleration cycle 19 times to establish 57 bunches for each ring. The overall filling time of both rings should be about 1 min. Table 1: RHIC Performance Estimates No. bunches 57 Bunch spacing (nsec) 224 Collision angle 0 Free space at crossing point (m) f9 Au P No. particles/bunch 1 x 109 1 x LO” Top energy (GeV/u) 100 250 Emittance (R mm mrad) 60 20 Diamond length (cm rms) 22 20 Beta* (m) Luminosity (cmw2 see-‘) w 2 ,” 102s 1.4 ,” 103’ Lifetime (hr) NlO >lO Beam-beam tune spread/crossing 3 x lo-’ 4 x 10-3 |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://epaper.kek.jp/e90/PDF/EPAC1990_0070.PDF |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
