Alan Krisch

Professor Alan Krisch passed away on December 5, 2020. Alan is survived by his wife, Jean; his daughter, Kathleen; and two brothers, Henry and Robert.

Professor Krisch directed Michigan's Spin Physics Center, which studies spin effects in violent elastic collisions of protons. These experiments need spin-polarized proton beams and spin-polarized proton targets. The Center led the development of the world's first high-energy polarized proton beams at the 12 GeV Argonne ZGS in 1973 and then at the 28 GeV Brookhaven AGS in 1983. These new capabilities allowed the Center to discover several large and totally unexpected spin effects in the violent collisions of spinning protons during the period 1975 to 1990. These experiments are now being extended to higher P_?Û² and higher energies. A 35-meter-long elastic recoil-proton spectrometer for the Michigan-led SPIN@U-70 experiment was installed at IHEP-Protvino 70 GeV U-70, which is Russia's largest accelerator; the first run occurred in April 2002. These experiments may continue at Brookhaven's new 100 GeV stored polarized proton beam in RHIC and at the very-high-intensity 50 GeV JHF in Japan, which should have its first beam in 2008.

To obtain even higher energy polarized proton beams at facilities such as the canceled 20 TeV SSC, Fermilab's 1 TeV Tevatron, DESY's 920 GeV HERA in Germany and Brookhaven's 250 GeV RHIC, the Center has used the Indiana University Cooler Ring to verify the Siberian snake concept for overcoming all depolarizing resonances, which destroy the polarization in such high energy rings. These Siberian snake experiments were very successful during the period 1989 to 2002. Thus, the SSC, Fermilab and DESY all asked the Center to design Polarized Proton Beam Capability for their rings. In July 1999, the Center submitted a very detailed report to DESY on polarizing its 920 GeV HERA Ring. More recently, MIT-Bates commissioned the Center to help accelerate polarized electrons in their 1 GeV Storage Ring and to provide spin-flipping capability for it. The Center recently moved its Siberian snake and spin manipulation experiments from IUCF to the higher energy COSY storage ring in Jülich, Germany.

The Center has also developed several state-of-the-art Solid Polarized Proton Targets that operate at 0.5 to 1.0 K temperatures and at 2.5 to 5.0 Tesla magnetic fields. The techniques of the World-class 1 K and 5 Tesla Target, which provides up to 96% polarization when operating in a very high-intensity beam, was copied at SLAC and Jefferson Lab. The Center recently developed the World's first Ultra-cold Spin-polarized Atomic-hydrogen Jet Target which operates at 0.17 K and 12 Tesla. This highly polarized Jet recently set a new record for high density.

The Ultra-cold Jet was to be the internal target for the Center's NEPTUN-A Experiment which was the first installed experiment at the 21-km circumference 400 GeV to 3 TeV UNK Accelerator/Collider at IHEP-Protvino in Russia. NEPTUN-A was approved to study the large and unexpected spin effects discovered in elastic scattering at Brookhaven's AGS, but UNK was delayed by Russia's financial problems.

Professor Krisch was a Fellow of the American Physical Society.

Selected Publications

First Spin Flipping of a Stored Spin-1 Polarized Beam (V.S. Morozov et al), Phys Rev Lett., 91, 214801 (2003).

Deuteron Displays Surprising Spin Gymnastics, CERN Courier, 43, No. 10 (December, 2003).

99.9% Spin-Flip Efficiency, CERN Courier, 42, No. 2, 6 (April, 2002).

Collisions Between Spinning Protons (A.D. Krisch), Scientific American, 255, 42-50 (August, 1987).

Field(s) of Study

• Elementary Particle Experiment