You will be presented with the full text of a science research paper. Please write an abstract for this paper. Your response should include the abstract and no additional text.

Paper text:
the primary purpose of the microboone @xcite experiment is to explore an anomaly in its predecessor , miniboone , ( sec [ sec : miniboone ] ) by utilizing the unique properties of a lartpc .
it will also be an important step in the u.s .
lartpc program , being the largest lartpc to be built in the u.s .
to date as well as achieving some important milestones in the technology worldwide .
microboone will be located at fermi national laboratory along the booster neutrino beam .
the detector hall will be located slightly upstream of the miniboone detector hall and below ground on the beamline .
microboone will contain 170 tons of lar with a fiducial volume of roughly 60 tons .
lartpcs consist of a volume of lar with an applied electric field produced by a potential difference across the detector ( 125 kv , or 500 v / cm in microboone ) , and planes of wires on the @xmath0 end of this field .
there are also often phomultiplier tubes ( pmts ) to see the scintillation light from the argon .
when a charged particle travels through the argon , it ionizes the argon atoms , producing ionization electrons along its path .
the ionization electrons rapidly reach terminal velocity and drift towards the wire planes due to the applied electric field .
microboone has 3 wire planes 
the first two are induction planes , which measure the induced current in the wires by the ionization electrons , and the third is a collection plane , which collects these electrons .
the information from these planes allows the 3d paths of the initial charged particles traveling through the detector as well as their deposited energy to be reconstructed ( figure [ fig : eventdisplay ] ) . from this
, we can reconstruct the energy of the neutrino that produced these charged particles .
the primary motivation for microboone is an anomalous result seen in the miniboone experiment .
miniboone is a cherenkov detector searching for @xmath1 neutrino oscillations .
miniboone measured an unexplained 3@xmath2 excess of events at low energies ( fig [ fig : miniboone ] ) .
this excess can be due to some unexpected background or new physics .
the main problem with determining the nature of this excess is that cherenkov detectors can not distinguish converting photons ( @xmath3 ) from electrons , since cerenkov detectors only have a  20 cm vertex resolution where @xmath4 2 cm or the ability to measure @xmath5 would be needed to distinguish @xmath6 s from @xmath7s .
microboone however , is sensitive to the different amounts of energy they deposit and can produce a high resolution reconstruction of events .
there is a clear separation in microboone between electrons , which deposit  1 mip of energy , and photons converted into electron - positron pairs , which deposit  2 mips of energy in the first few centimeters of their tracks ( fig [ fig : egamma ] ) .
candidate data as a function of energy .
an excess of events above background is visible at low energies.,width=377 ]    ) , width=302 ]      microboone is also an important stage in the development of lar technology in the community .
microboone will be the largest lartpc to be built in the u.s .
it will also be the first lartpc to attempt to drift ionization electrons 2.5 m . demonstrating this 2.5 m drift is an important milestone which must be achieved in order to be able to build larger lartpcs .
the goal of our lartpc r&d is to make this technology a viable option for next generation kiloton scale detectors .
lartpc technology has many features that can benefit neutrino physics , but we first must demonstrate the scalability of the technology . some of the challenges that microboone will be addressing are noise - reducing cold electronics , lar purity in larger detectors , analysis tools , and understanding cross sections in lar .
argoneut @xcite has already made important measurements of cross sections in lar , but microboone will build on this with its larger fiducial volume and higher statistics .
microboone has a variety of other physics goals as well .
firstly , the low energy neutrino cross section measurements are an important physics goal .
it is important to understand how to model neutrino interactions on different nuclei .
microboone is also sensitive to a burst supernova .
it is sensitive to all neutrino species for elastic scattering , charged current , and neutral current events .
this is not unique to lar , but we can learn a lot from detecting these neutrinos in lar , particularly in future larger detectors .
we are also able to prepare for future proton decay searches ( @xmath8 ) .
microboone is not large enough to see proton decay , but we can develop particle i d , triggers , and understand background .
the ability to see proton decay is a very attractive feature of lar detectors as the outgoing k is below cherenkov threshold and therefore invisible to cherenkov detectors , which are currently the leading detector type for kiloton scale detectors .
microboone is also sensitive to @xmath9 , the fraction of proton spin carried by the strange quark , through neutral current elastic scattering .
this is impossible for most detectors because it is difficult to tell protons from neutrons , but liquid argon detectors can measure the energy of the outgoing proton and may be able to see the disconnected neutron - proton vertex . measuring @xmath9 in lar will help us to better understand proton spin .
lastly , microboone will be able to search for exotic physics such as decays of exotic heavy particles .
while the information provided by the argon scintillation light is not directly used in the determination of the energy of the incident neutrinos , the @xmath10 it provides is required . without it , there is some uncertainty between where the event occurred in the detector and when the event took place , since we only know when the event reached the wire planes .
a light collection system allows us to reject background by comparing interaction time with the beam time structure , which is crucial for a surface detector like microboone .
it also allows us to trigger on interesting non - beam events , which is necessary in order to study events like from supernovae or proton decay in liquid argon . knowing the exact location of an event can also allow corrections for charge losses and diffusions as a function of drift distance which allows for a more accurate measurement of energy deposits .
the light that we are interested in measuring is the scintillation light of the argon .
there are two paths for scintillation light to be produced @xcite @xcite :    the fast scintillation path : :    makes up about 25% of the scintillation light .
as a charged particle    travels through the lar , it may excite the argon atoms .
when this    occurs , the excited argon atom may combine with another argon atom to    form a singlet state excimer which will then decay to form two argon    atoms and a 128 nm photon .
this process takes   6ns .
the slow scintillation path : :    makes up the other 75% of the scintillation light and begins with the    charged particle traveling through the lar ionizing the argon atom    ( the same process by which the ionization electrons are produced ) . the    resulting argon ion can recombine with another argon atom and another    electron in order to produce a triplet state excimer .
this excimer    then decays into a singlet state excimer , which as before , decays into    two argon atoms and a 128 nm photon .
this process takes 1.6    @xmath11    this 128 nm scintillation light is in the vacuum uv , a range of wavelengths which is unable to pass through most substances , including air .
this 128 nm light is also unable to pass through the glass of a photomultiplier tube , so we must first shift the light to wavelengths in the visible range in order to detect it .      in order to detect the argon scintillation light with photomultiplier tubes ( pmts )
, we use a wavelength shifting material called tetraphenyl butadiene ( tpb ) to coat acrylic plates positioned in front of the pmts .
tpb absorbs light in the uv and re - emits in the visible ( fig [ fig : tpbspectrum ] ) . the efficiency for re - emission of light absorbed at 128 nm has been determined by ref @xcite to be 120% for a film of pure tpb made through vacuum evaporation .
we plan to use a coating of 50% tpb and 50 % polystyrene ( ps ) for our plate coating , which we have measured to have about 50% of the efficiency of the evaporative coating .
we find that this mixture makes the plates more durable and also more cost effective .
the tpb coated plates have a diameter of 12 " and will be placed on top of posts so that they are suspended directly above the pmts ( fig [ fig : pmtmount ] ) .
the posts , which are made of the thermally resistant material polyether ether ketone ( peek ) , also serve to hold the pmt in place . there will be 30 pmts in microboone arranged behind the wire planes along the side of the detector outside of the electric field region ( fig [ fig : pmtmount ] ) .
while the microboone light collection system is a good fit for a  100 ton lar detector , there are many challenges this system would face when scaling up to a larger multi - kiloton detector .
the proposed multi - kiloton detectors use modules which each have their own electric fields and wire planes , so that the electric field does not have to be applied across too large of a distance , as the necessary field strength would be difficult to work with . having a light collection system only on the edges of such
a detector is unlikely to be successful , as the light has a large probability of being absorbed during multiple rayleigh scatters .
having a system that could slide in between wireplanes would be a solution to this problem .
our solution is a lightguide detection system @xcite where lightguides are bent to guide light adiabatically into pmts which are placed out of the electric field region .
( see fig [ fig : tesspaddle ] ) .
these lightguides would take up far less of the fiducial volume of the detector than a system of pmts , as well as being able to go places that pmts can not such as in electric fields and tighter spaces .
a much larger area of coverage is also possible .          in order for lightguiding to occur without the light having originally entered at the end of the guide
, the light must be produced inside the guide .
this is accomplished by embedding the tpb in a thin film of polystyrene ( ps ) , a good index of refraction match to acrylic , and applying this coating to the surface of the acrylic .
the coating is a mixture of 25% tpb to 75% ps .
when the uv light hits a tpb molecule , the outgoing visible light is emitted isotropically inside the film and may be totally internally reflected if the light is emitted above the critical angle of the guide .
this coating must be optically smooth for better lightguiding properties .
the lightguides are tested using a small @xmath12 disk source placed @xmath13 5 mm from the lightguide which produces @xmath14 mev @xmath15 particles .
these @xmath16 travel @xmath17 in argon , producing photons along its path through the mechanism described in section [ sec : light_in_lar ] which may hit the lightguide and be transmitted to a r7725-mod pmt .
our setup is shown in fig [ fig : lightguide_setup ] .
the pmt observes a multi - photoelectron prompt pulse from the fast scintillation light , which arrives all at once , as well as single photoelectron ( p.e . )
late pulses ( fig [ fig : pulse ] ) .
disk source placed @xmath185 mm from the lightguide emits photons through argon scintillation which hit the lightguide , are shifted , and reemitted down the lightguide and into the pmt , width=188 ]        these pulses are calibrated in two ways in ref @xcite .
we must define one p.e . in terms of adc counts .
the first method is to define one p.e . by the late light , as most of the late light pulses only contain one p.e . , and take the mean of the gaussian that results by fitting the pulse heights of these late light charges .
the second method is to fit the early pulse with equally spaced gaussians ( with the spacing allowed to float ) .
there are natural peaks in the data , representative of a poisson distribution around each number of p.e . that a pulse can have .
both of these methods yield the same answer . for our new studies
, we are using the integrated pulse charge and calibrate using the late light only for simplicity .
the resulting fits @xcite yield an average of  8 p.e . and
an attenuation of  75 cm . using 1 m paddles ( 8 lightguides curving into a 2 in pmt ) , we would need 27 paddles to detect a 40 mev proton ( defined as observing 5 p.e . ) in microboone .
this is practical , though not nearly as good as the current microboone system .
since this paper , we have switched to using uv transmitting acrylic for our coating in which to embed the tpb , and switched to using cast acrylic instead of extruded acrylic for our lightguides , as the cast acrylic should have a higher attenuation length . with these new lightguides
, we are seeing an average of 35 p.e .
per @xmath15 , which is a factor of 4 more light .
this makes this r&d even more promising .
we plan to set up a demonstration detector ( fig [ fig : demodetector ] . with six 20 cm wide by 40 cm long paddles of eight lightguides each in order to demonstrate this technology as well as measure the muon lifetime in argon .
microboone is an important state in the development of future lar tpcs .
it will also help our understanding of the miniboone experiment as well as making other important physics contributions .
the new developments in lightguide r&d for general purpose light collection in lar look promising , and may be a solution to the problems that will be faced when scaling up systems which are currently in use to the kiloton scale .
the microboone experiment is a 170 ton liquid argon time projection chamber ( lartpc ) that will begin running at fermilab in 2013 . 
 its primary physics goal is to explore the low energy excess of events seen by the miniboone experiment and it is the next step in the r&d to make lar a viable option for future large neutrino detectors . 
 this talk presented an overview of the microboone experiment with an emphasis on the light collection system and recent technical advances .