[time-nuts] MINOS Status on Measuring Neutrino Velocity
bill at iaxs.net
Thu Feb 23 00:42:56 UTC 2012
Congratulations on receiving the funding to keep the experiment alive
and to get the right equipment. I've thought of our conversation in
early November many times.
Is it coincidence that your posting arrives on the same day that a 60
nS error was found in the OPERA experiment?
bill at iaxs.net
From: Marvin Marshak
Sent: Wednesday, February 22, 2012 2:08 PM
To: time-nuts at febo.com
Subject: [time-nuts] MINOS Status on Measuring Neutrino Velocity
The MINOS Collaboration has made progress in its effort to use the Fermilab
to Soudan MN neutrino beam to investigate the effect reported by the OPERA
Collaboration of neutrinos travelling faster than the speed of light. The
current MINOS methodology has two parts: (1) to retrospectively analyze data
collected since 2005 with timing established by Truetime XL-AK GPS units and
(2) to use new data to be collected during March and April 2012 with
significantly enhanced timing instrumentation. The retrospective analysis
will include considerably more data and improved analysis algorithms,
compared with the observations published by MINOS in 2007.
In this email, I will focus on the new instrumentation. MINOS now has three
timing stations. The first station is located at a point called MI-60, which
is at the Fermilab Main Injector in Batavia IL, an accelerator that produces
the proton beam that eventually results in the neutrino beam. The MI-60
station monitors the antecedent proton flux as a function of time. The
second station is located in the MINOS Neutrino Near Detector, which is
approximately 1 km from the proton target. The third station is located at
the MINOS Neutrino Far Detector in Soudan MN, approximately 735 km from the
proton target. Each timing station includes an HP5071A cesium clock,
installed with help from the U.S. Naval Observatory; a Novatel
dual-frequency code and carrier phase GPS receiver, modified by and
installed with help from NIST; and multiple Agilent 53230A time
interval/frequency counters. Each station also has ancillary hardware,
including distribution amplifiers, optical fiber links, temperature
stabilization chambers and monitoring computers. Each station also has
instrumentation to measure and monitor changes in propagation delays in the
various cables and optical fiber links, particularly the long ones between
surface GPS receivers and the deep underground detectors. An additional HP
5071A will be used for round trip travel between Fermilab and Soudan. The
clock synchronization between the two ends of the beam will also be checked
using other methods with help from USNO and NIST. I expect to describe these
methods later when arrangements are more complete.
These stations enable three inter-station measurements:
. MI-60 to Near Detector: Most distance travelled by charged particles;
should be very close to speed of light.
. MI-60 to Far Detector: Almost entirely neutrino propagation delay.
. Near Detector to Far Detector: Entirely neutrino propagation delay.
We have just started operating the HP5071A cesium clocks in the last few
days and are interested in suggestions for optimal operation and monitoring
of these units. The HP5071As can be controlled and read out via a serial
the device has many operating parameters it can report. Which of those
parameters are most useful for long-term monitoring of the clock stability?
Are there subtle problems in using these units?
The next few months should produce interesting results and I will try to
keep the list informed on progress.
Marvin L. Marshak
College of Science and Engineering Professor
University of Minnesota
116 Church Street SE
Minneapolis MN 55455 612-624-1312 612-624-4578 (fax)
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