The design of the magnet for the GEM detector at the SSC is described. It is an 18m inner diameter, 30m long superconducting solenoid, with a magnetic field of 0.8T. The basic solenoidal field is shaped by large ferromagnetic cones, to improve detector performance in the ends of the solenoid. Because of the system`s large size and mass, field-fabrication on-site at SSC is required. The challenges in this process, together with the large stored energy of the system, 2.5 GJ, have lead to novel design choices in several areas, including the conductor. The design of the conductor, cold mass, vacuum vessel, cold mass supports, thermal shields, forward field shapers, and auxiliary systems are described.

The Wavelet/Scalar Quantization (WSQ) gray-scale fingerprint image compression algorithm involves a symmetric wavelet transform (SWT) image decomposition followed by uniform scalar quantization of each subband. The algorithm is adaptive insofar as the bin widths for the scalar quantizers are image-specific and are included in the compressed image format. Since the decoder requires only the actual bin width values -- but not the method by which they were computed -- the standard allows for future refinements of the WSQ algorithm by improving the method used to select the scalar quantizer bin widths. This report proposes a bit allocation procedure for use with the first-generation WSQ encoder. In previous work a specific formula is provided for the relative sizes of the scalar quantizer bin widths in terms of the variances of the SWT subbands. An explicit specification for the constant of proportionality, q, that determines the absolute bin widths was not given. The actual compression ratio produced by the WSQ algorithm will generally vary from image to image depending on the amount of coding gain obtained by the run-length and Huffman coding, stages of the algorithm, but testing performed by the FBI established that WSQ compression produces archival quality images at compression …

The superconducting solenoid magnet for the GEM detector poses unusual fabrication and handling challenges because of its extraordinary size. It will be more than 30% larger in diameter than the largest existing particle detector coils. Each of the two coil elements that compose the air-core solenoid, will be about 19 meters in diameter and 15 meters long. Major components weighing as much as 1500 Mg must be transported and manipulated at the Interaction Region 5 (IR5) fabrication site of the SSC Laboratory as the magnets are fabricated. Because of their large size, the magnets will be fabricated, assembled and tested at special purpose facilities at the IR5 site. The site-use plan must accommodate the fabrication of other detector components and the assembly of large flux shaping iron structures in a timely manner to allow subsequent testing and detector assembly. Each cold mass will be composed of twelve 45-Mg coil windings that are joined prior to assembly into the 19-m diam annular cryostat.