Editing Super-Kamiokande (section)

==Monitoring system==
===Online monitoring system===
An online monitor computer located in the control room reads data from the DAQ host computer via an FDDI link. It provides shift operators with a flexible tool for selecting event display features, makes online and recent-history histograms to monitor detector performance, and performs a variety of additional tasks needed to efficiently monitor status and diagnose detector and DAQ problems. Events in the data stream can be skimmed off and elementary analysis tools can be applied to check data quality during calibrations or after changes in hardware or online software.<ref name="auto1" />

===Realtime supernova monitor===
To detect and identify such bursts as efficiently and promptly as possible Super-Kamiokande is equipped with an online supernova monitor system. About 10,000 total events are expected in Super-Kamiokande for a supernova explosion at the center of the Milky Way Galaxy. Super-Kamiokande can measure a burst with no dead-time, up to 30,000 events within the first second of a burst. Theoretical calculations of supernova explosions suggest that neutrinos are emitted over a total time-scale of tens of seconds with about a half of them emitted during the first one or two seconds. The Super-K will search for event clusters in specified time windows of 0.5, 2, and 10&nbsp;s.<ref name="auto1" />

Data are transmitted to realtime SN-watch analysis process every 2 minutes and analysis is completed typically in 1&nbsp;minute. When supernova (SN) event candidates are found, <math>{R_\text{mean}}</math> is calculated if the event multiplicity is larger than 16, where <math>{R_\text{mean}}</math> is defined as the average spatial distance between events, i.e.
:<math>{R_\text{mean}} =\frac {\sum_{i=1}^{{N_\text{multi}}-1} \sum_{j=i+1}^{{N_\text{multi}}} |{r_\text{i}}-{r_\text{j}}|} {{N_\text{multi}} {C_\text{2}}}</math>

Neutrinos from supernovae interact with free protons, producing positrons which are distributed so uniformly in the detector that <math>{R_\text{mean}}</math> for SN events should be significantly larger than for ordinary spatial clusters of events. In the Super-Kamiokande detector, <math>{R_\text{mean}}</math> for uniformly distributed Monte Carlo events shows that no tail exists below <math>{R_\text{mean}}</math>⩽1000&nbsp;cm. For the "alarm" class of burst, the events are required to have <math>{R_\text{mean}}</math>⩾900&nbsp;cm for 25⩽<math>{N_\text{multi}}</math>⩽40 or <math>{R_\text{mean}}</math>⩾750&nbsp;cm for <math>{N_\text{multi}}</math>>40. These thresholds were determined by extrapolation from SN1987A data.<ref name="auto1" /><ref>{{citation |title=Observation of a neutrino burst from the supernova SN1987A |author1=Hirata, K |journal=Physical Review Letters |volume=58 |issue=14 |pages=1490–1493 |date=6 April 1987 |bibcode=1987PhRvL..58.1490H |display-authors=etal |pmid=10034450 |doi=10.1103/PhysRevLett.58.1490 |doi-access=free}}</ref>

The system will run special processes to check for spallation muons when burst candidates meeting "alarm" criteria and make a primary decision for further process. If the burst candidate passes these checks, the data will be reanalyzed using an offline process and a final decision will be made within a few hours. During the Super-Kamiokande I running, this never occurred.
One of the important capabilities for [Super-Kamiokande] is to reconstruct the direction to supernova. By neutrino–electron scattering, <math>\nu_\text{x} + e^- \to \nu_\text{x} + e^-</math>, a total of 100–150 events are expected in case of a supernova at the center of the Milky Way Galaxy.<ref name="auto1" /> The direction to supernova can be measured with angular resolution
:<math>\delta \theta \sim {30^\circ \over \sqrt{N}}</math>

where N is the number of events produced by the ν–e scattering. The angular resolution, therefore, can be as good as δθ~3° for a supernova at the center of the Milky Way Galaxy.<ref name="auto1" /> In this case, not only time profile and the energy spectrum of a neutrino burst, but also the information on direction of supernova can be provided.

===Slow control monitor and offline process monitor===
There is a process called the "slow control" monitor, as part of the online monitoring system, watches the status of the HV systems, the temperatures of electronics crates and the status of the compensating coils used to cancel the geomagnetic field. When any deviation from norms is detected, it will alert physicists to prompt to investigate, take appropriate action, or notify experts.<ref name="auto1" />

To monitor and control the offline processes that analyze and transfer data, a sophisticated set of software was developed. This monitor allows non-expert shift physicists to identify and repair common problems to minimize down time, and the software package was a significant contribution to the smooth operation of the experiment and its overall high lifetime efficiency for data taking.<ref name="auto1" />