Physical Sciences and Mathematics Commons^™

A Quasiparticle Trap Assisted Transition Edge Sensor For Phonon Mediated Particle Detection, K. D. Irwin, S. W. Nam, Blas Cabrera, B. Chugg, Betty A. Young

Physics

ABSTRACT We have demonstrated the operation of composite superconducting tungsten and aluminum transition‐edge sensors which take advantage of quasiparticle trapping and electrothermal feedback. We call these devices W/Al QETs (quasiparticle‐trap‐assisted electrothermal feedback transition‐edge sensors). The quasiparticle trapping mechanism makes it possible to instrument large surface areas without increasing sensor heat capacity, thus allowing larger absorbers and reducing phonon collection times. The sensor consists of a 30‐nm‐thick superconducting tungsten thin film with T_c∼80 mK deposited on a high‐purity silicon substrate. The W film is patterned into 200 parallel lines segments, each 2 μm wide and 800 μm long. Eight …

Santa Clara Magazine, Volume 37 Number 4, Fall 1995, Santa Clara University

Santa Clara Magazine

8 - OF QUARKS, OBJECT IDENTIFICATION, AND PORPHYRIN MOLECULES SCU undergraduates get a taste of scientific research. By Miriam Schulman

14 - WHAT'S YOUR BOTTOM LINE? By investing in mutual funds that reflect their values, an increasing number of shareholders hope to put their money where their morals are. But can socially responsible investing really change the world? By Jeff Brazil ' 85

22 - A BIG ENOUGH UMBRELLA Tens of thousands of women from around the world gather for a unifying-albeit rainy- conference in China. Photographs By Kim Johnson ' 87

26 - THE ART OF MATHEMATICS For every …

Santa Clara Magazine, Volume 37 Number 3, Summer 1995, Santa Clara University

Santa Clara Magazine

6 - GARBAGE IN: GOODS OUT Lee Hornberger ' 69, associate professor of mechanical engineering, has only one word to say to you: plastics. By Maureen Mclnaney '85

10 - SCU 101 More than a hundred (count 'em) things every student shou ld do before graduating from Santa Clara.

16 - CHIAPAS: ROOTS OF A REBELLION Members of the SCU community bear witness to an indigenous struggle. By Trina Kleist '80 Photographs by Charles Barry

22 - PRESENTING PARADISE A modern translation with commentary helps readers scale the heights of Dante's heaven. By James Torrens, S.J.

24 - HAVE BALL, …

Santa Clara Magazine, Volume 37 Number 2, Spring 1995, Santa Clara University

Santa Clara Magazine

6 - MORE THAN A CATHOLIC EDUCATION Why students from other faiths choose Santa Clara and what they find here. By Elise Banducci '87

10 - WALKING WITH THE PEOPLE OF DOLORES MISSION For a young Jesuit, the people of his East Los Angeles parish have much to teach. By Gregory Bonfiglio '82, S.J.

16 - A GOOD SPANKING? Deeply concerned about youth crime and disorder, many people say corporal punishment could be the answer for unruly students. But does it work? By Miriam Schulman

22 - MARKET-DRIVEN NEWS: LET THE CITIZEN BEWARE Increasingly, what's considered news is being defined …

Local Politics In The Time Of Turabi's Revolution: Gender, Class And Ethnicity In Western Sudan, Michael Kevane, Leslie C. Gray

Economics

In one small village in western Sudan local political struggles over power and resources are enmeshed in discursive struggles over representations of gender, ethnicity, class and community. Analysis of two specific conflicts illustrates this point. In one conflict over control of a village grain co-operative some villagers sought to exclude women, West African immigrants and the poor from participating in political decision-making. In a second conflict over a roadside market these same villagers, empowered by the divisive rhetoric and policies of the National Islamic Front regime, again mobilised dominant representations of class, gender and ethnicity in an attempt to prevent …

Ion‐Implanted Charge Collection Contacts For High Purity Silicon Detectors Operated At 20 Mk, Betty A. Young, K. M. Yu

Physics

We have developed a technique for fabricating high resolution, ohmic contacts for cryogenic silicon detectors operated at temperatures well below 1 K. In this paper, we give a detailed description of the techniques used to fabricate these boron‐implanted contacts, and present characterization data obtained on 24 test samples studied during the design phase of our program. We then describe the fabrication and operation of a 23 g prototype silicon hybrid detector which simultaneously senses both the phonons and ionization produced by a single event, and which incorporates these new contacts into its design. Finally, we present data obtained using a …

Santa Clara Magazine, Volume 37 Number 1, Winter 1995, Santa Clara University

Santa Clara Magazine

6 - THE JESUIT CASE DECLASSIFIED Secret documents reveal what the United States knew.... and what it failed to do about the Jesuit murders in El Salvador. By Peter Kornbluh

10 - EASTERN ENLIGHTENMENT SCU's new religion chair draws from her latest book to discuss how Christians can derive a greater understanding of their own faith through an appreciation of Buddhism. By Denise Lardner Carmody

13 - WASTE NOT As part of SCU's Institute on Ecology, students, faculty, and staff assess how well the University is using its own environmental resources.

17 - THE DOMESTIC CHURCH MEETS THE PARISH CHURCH …

Collection Of Athermal Phonons Into Doped Germanium Thermistors Using Quasiparticle Trapping, S. M. Grannan, Betty A. Young, Andrew E. Lange, S. Labov, Bernard Sadoulet, J. Emes, Eugene E. Haller

Physics

We have developed a low‐temperature particle detector that uses a novel quasiparticle trapping mechanism to funnel athermal phonon energy from an 80 mg Ge absorber into a 1.6 mg doped Ge thermistor via a superconducting Al film. We report on pulse height spectra obtained at 320 mK by scanning a ²⁴¹Am alpha source along the device, and show that up to 20% of the energy deposited in the Ge absorber by a 5.5 MeV alpha particle interaction can be collected into a thermistor via quasiparticle trapping. We show that this device is sensitive to the position of an alpha …