An Analysis of Variations in the Half-Lives of Long-Lived Isotopes. CAROLYN MELDGIN (Harvey Mudd College Claremont, CA 91711) RICHARD B. FIRESTONE (Lawrence Berkeley National Laboratory, Berkley, CA, 94720)

It is commonly held that the half-life of an isotope is a constant. However, there is less agreement between different measurements than one would expect. Analyzing a database of 860 measurements for isotopes with a half-life greater than one day, it was determined that the average ², comparing measurements of the same isotope, was 7.04, rather than 1.00, the expected value. The purpose of this analysis was to select a subset of values from the original database that could be considered significant and determine what factor(s) influenced the agreement between values. Statistical analysis revealed that the measurements of half-lives of isotopes with large masses showed larger ² values. Nuclei can exist in different energy states, and heavier nuclei have more isomeric states available, often with half-lives comparable to that of the ground state. It is hypothesized that these nuclei show less agreement because when experimenters created the parent isotope for their experiment they created an isomer as well. Different experiments may populate the two states differently leading to varying results. Another factor influencing the measurement in half-life is decay energy. For isotopes with small decay energies, the associated half-lives tend to show poorer agreement. It is possible that the half-lives are affected by the chemical environment of the isotope when the decay energy is small. Spin, parity, fractional uncertainty, and mode of decay do not appear to influence the comparison of measurements.

Background Mitigation of HIghly-Segmented HPGe Detectors in a Low-Background Environment. MICHELLE PERRY (Florida State University Tallahassee, FL 32301) KEVIN LESKO (Lawrence Berkeley National Laboratory, Berkley, CA, 94720)

We present the first study of a highly-segmented HPGe detector with pulse shape discrimination in a low background environment. The detector consists of an 8x5 higly segmented coaxial HPGe crystal shielded with 5 cm of normal lead. Data was collected at the Oroville low-background counting facility to study detector behavior and backgrounds applicable to the proposed Majorana neutrinoless double-beta decay experiment. Waveform analysis and development of data analysis methods for the detector is presented.

Cosmic Rays: A Trip into the Atmosphere. CHRISTOPHER TAYLOR (West Hills College Lemoore, CA 93245) TOM KNIGHT (Lawrence Berkeley National Laboratory, Berkley, CA, 94720)

The constant bombarding of cosmic rays (charged particles originating from either the sun or super nova) upon the earth's atmosphere has been a concern for scientist for over 100 years, and in years past and present, a major obstacle for NASA and airline workers. Since Victor Hess' balloon ride with an electroscope, scientist have known that the higher the altitude the more cosmic rays that will be detected. Scientists have often wondered if these particles have negative effects on the human body if too closely exposed to them. Using a cosmic ray detector which was built with the following components: 1) Scintallator paddles; captures falling rays and turns them into light, 2) Photo Multiplier Tubes (PMT); captures these light rays, 3) Circuit board; turns signal from PMT into a quantitative number, and 4) The detector's outer shell; gave 3 different angles of collection (30,60,90 degrees), and picking two places to take the readings, one high in elevation (Mt. Diablo) and one barricaded by man made structures (Caldecott Tunnel), scientists will be able to show if and how the atmosphere and structures affect these particles. This test will show that while altitude increases the amount of rays detected, concrete and earth block many of them. NASA and the FAA need to be aware and concerned about these rays in hopes of protecting our nations astronauts, airline pilots and attendants from these rays and their possible harm.

Determining Specific Activity of [13 N] Ammonia. JONATHAN HOFFMAN (Elcamino Community College Torrance, CA 90503) JIM O'NEIL (Lawrence Berkeley National Laboratory, Berkley, CA, 94720)

The specific activity of a radioactive species is a quantization of the amount of radioactive isotope in comparison with non radioactive isomers within the same species. This quantitative assessment is generally expressed as a ratio of activity (e.g. mCi) to mass (grams or moles). In the context of diagnostic radiopharmaceuticals, specific activity provides a method of measuring the concentration of a radioactive drug to a non radioactive drug. Maximizing the specific activity within a given substance helps to minimize the potential of unwanted side effects. Therefore the higher the specific activity of a drug, the smaller the amount of injected non radioactive drug. Using High Performance Liquid Chromatography-Ion Chromatography (HPLC-IC), ammonium ions were separated from injected samples and their concentrations where determined by electrochemical conductivity detection. A series of injections were made onto a Hamilton PRP-x200 Cation Exchange column at a flow rate of 2 ml/min at a constant pressure of 900psi. Measuring the detector response per injected mass of ammonium nitrate standards (0.15mmol/L to 0.000015mmol/L) provided data for a standard absorbance curve. Subsequently, the standard curve can then be used in determining concentrations of unknown ammonium samples by comparison to the detector response. Radioactive samples of [13 N] ammonia can then be analyzed for radioactivity using a dose calibrator, and the concentrations can be determined by the HPLC-IC and standard curve. Thus the specific activity is provided by calculating the ratio of radioactivity to mass of the sample. Furthermore, a calibration curve for the conductivity detector was successfully constructed. Future studies using radioactive [13 N] ammonia can now refer to the ammonium curve in order to calculate the specific activity of an unknown sample.

Digital Signal Processing for Active Pixel Sensors. JEFFREY LEVESQUE (Rensselaer Polytechnic Institute Troy, NY 12180) HOWARD MATIS (Lawrence Berkeley National Laboratory, Berkley, CA, 94720)

Active pixel sensors (APS) are a recent development in complimentary metal-oxide semiconductor (CMOS) technology. The Relativistic Nuclear Collisions group at Lawrence Berkeley National Laboratory has proposed using active pixel sensors in a new vertex detector to measure short-lived particles resulting from high energy collisions at the Relativistic Heavy Ion Collider (RHIC). Expected performance must be evaluated to maximize hit-finding efficiency before implementing an APS detector. In this study, a standard threshold-based algorithm was used to compare efficiencies before and after applying a Gaussian smoothing digital signal processing (DSP) technique. Different levels of noise were attained by recording data at several operating temperatures using the MIMOSA-5 APS chip, provided by the Strasbourg IReS group. Simulated particle hits were embedded at known locations in the data, and then a hit-finding algorithm was used to search for these hits. For a chosen maximum of 100 falsely classified hits per square centimeter, more embedded hits were correctly found in smoothed data than in raw data. Gaussian smoothing is therefore an effective method for reducing noise.

Digital Signal Processing for Active Pixel Sensors. JEFFREY LEVESQUE (Rensselaer Polytechnic Institute Troy, NY 12180) HOWARD MATIS (Lawrence Berkeley National Laboratory, Berkley, CA, 94720)

Active pixel sensors (APS) have been a promising development in complimentary metal-oxide semiconductor (CMOS) technology. The Relativistic Nuclear Collisions group at Lawrence Berkeley National Laboratory has proposed using active pixel sensors in a new vertex detector to measure short-lived particles resulting from high energy collisions at the Relativistic Heavy Ion Collider (RHIC). The expected performance must be evaluated before implementing an APS detector. In this study, a standard threshold-based algorithm was used to compare efficiencies before and after applying a Gaussian smoothing digital signal processing (DSP) technique to APS data. Different levels of noise were attained by recording data at several operating temperatures using the MIMOSA-5 chip, provided by the Institut de Recherches Subatomiques (IReS) of Strasbourg, France. Simulated particle hits were embedded at known locations in the data, and then a hit-finding algorithm was used to search for these hits. Overall efficiencies were calculated by integrating percentages of found hits over a 1.0 GeV/c pion energy spectrum for the MIMOSA-5. Results were compared based on efficiency versus the number of incorrect hits found. For all studied noise levels, smoothed data achieved higher efficiencies at reasonable false hit totals. Gaussian smoothing was therefore deemed to be effective method for improving APS efficiency.

Intensive Research Institute. MEAGAN JAMIESON (Fresno State Fresno, CA 93726) TOM KNIGHT (Lawrence Berkeley National Laboratory, Berkley, CA, 94720)

The Intensive Research Institute participated in four, two week workshops; Building a Cosmic Ray Detector with Howard Matis, Natural Terrestrial radioactivity with Allan Smith, Neutron Activation with Howard Shugart, and Finger Print Analysis and spectromicroscopy with Michael Martin. Our main goal is to relate newly acquired knowledge and skills from the workshops to high school and middle school mathematics and science standards. We built a cosmic ray detector and proved through experiment that cosmic rays come from the atmosphere not the earth. In the workshop Natural Terrestrial radioactivity we conducted two experiments. We tested an air filter and soil near our building to see what elements they contain. The air filter contained Uranium and Thorium. The soil contained Uranium, Thorium and Potassium. We bombarded three types of medals with neutrons in the workshop, Neutron Activation. In doing this experiment three isotopes were created; Cobalt (Co-58), Magnesium (Mg-27), and Sodium (Na-24). A forensics type experiment was conducted using infrared spectroscopy. We tested a powdery substance and found which spectra's it contained. We then analyzed the spectra of two sets of fingerprints, one with the powdery substance and one without. The powdery substance and the fingerprint with the substance had some of the same spectra's. The main goal was achieved because we came up with standards for every workshop and we now have more ideas of lesson plans that can be used to relate science and mathematics.

Simulation of Cosmogenic Backgrounds in Underground Detectors. KAI HUDEK (Colorado School of Mines Golden, CO 80401) KEVIN LESKO (Lawrence Berkeley National Laboratory, Berkley, CA, 94720)

This project is intended to further the understanding of neutron backgrounds in Majorana. Neutrons produced by cosmic muons in rock surrounding an underground facility can generate irreducible backgrounds in detectors and in some experiments determine the sensitivity. Understanding the muon-induced production and the response of underground detectors to neutrons is crucial for the design of next generation low background experiments. Surface muons are generated using the rejection method according to [7, 5], and used as inputs for neutron generating distribution functions [6]. These distribution functions are, in turn, sampled using the rejection method and the resulting neutrons are input into MaGe, the Majorana Monte Carlo package.

Substance Based Fingerprint Analysis Using Infrared Spectromicroscopy. RODGER BAILEY (California State University Fresno Fresno, CA 93702) THOMAS KNIGHT (Lawrence Berkeley National Laboratory, Berkley, CA, 94720)

Traditional fingerprint analysis has involved the comparison of the physical characteristics of a fingerprint, using the patterns of various ridges as a means of identification for an individual. Infrared Fingerprint Spectroscopy focuses on the tiny traces of material that remain in the fingerprints after handling a substance. Molecular bonds in substances move in three distinct patterns, symmetrical, asymmetrical and bending. When these bonds are moving in a symmetrical or bending pattern, they interact with IR light and absorb energy at various frequencies, depending upon the substance. Each type of bond moves, or resonates, at a specific frequency. By measuring the frequency of absorbed infrared light, chemical bond information can be obtained and the substance can be identified. This adds another dimension to fingerprint analysis by matching trace particles in a fingerprint to a specific substance. An infrared spectrum was obtained from an unidentified substance by mixing the sample with KBr, compressing it into a crystal and analyzing it in the FTIR Spectrometer. The spectrum indicated the presence of Silicone in the sample. Two fingerprints were obtained, one as a control and the other contaminated with the unknown substance. Each fingerprint was analyzed, using the FTIR Spectrometer, and their respective infrared spectra were compared with that of the unidentified substance. The spectrum obtained from the control fingerprint did not indicate the presence of Silicone. The spectrum obtained from the contaminated fingerprint matched that of the unidentified substance, conclusively linking the fingerprint with the substance. Beyond identifying unknown compounds, IR Spectroscopy can be used to determine what chemical groups are present in a compound and its optical conductivity.

Unveiling a new state of Matter: Studying Quark-Gluon Plasma with Charm Hadron Probes. LARA PIERPOINT (University of California, Los Angeles Los Angeles, CA 90095) KAI SCHWEDA (Lawrence Berkeley National Laboratory, Berkley, CA, 94720)

51 institutions worldwide are working in collaboration to create and study a new state of matter called quark-gluon plasma (QGP) with the Solenoidal Tracker at RHIC (STAR) device at Brookhaven National Laboratory. Characterization of QGP, if it exists, can be accomplished by studying charm-quark hadrons in STAR. However, in order to observe charm hadron behavior, more precise measurements are needed than those currently possible with the detectors in place. The relativistic nuclear collisions group (RNC) at Lawrence Berkeley Lab is developing a new detector subsystem that will utilize active pixel sensing (APS) technology to measure charm hadrons in STAR. One of its main science goals will be to reveal the transverse momentum spectrum of the charm hadrons in gold-gold collisions. Monte Carlo simulations of the new sub-system detector (Heavy Flavor Tracker, or "HFT") show that it will be successful in distinguishing the spectrum of charm hadrons in the non-flow (no QGP) case from the spectrum in the flow (QGP) case.