Link to Fulltext

More documents

Recommendations

Info

Hadronic showers A hadron shower occurs when a hadron scatters inelastically with a nucleus, producing more hadrons and so on.The scale is set by the absorption length of the material, which is about 75 cm for ice. The maximum of the shower occurs at £ ¡ ¨¢ © ¦ ¡ ¡ ¥¤ (41) ¡ ¤¢ As for electromagnetic showers, the length of a hadronic shower grows as the logarithm of the energy. However, the energy fluctuations are larger, since the fraction of § mesons fluctuates greatly. The contribution to the deposited energy of that particle, which decays to two ¥ showering electromagnetically, is larger than that of § © and this leads to fluctuations in energy [32]. In a hadron shower, 30% of the energy is lost by the breakup of nuclei, nuclear excitations, protons, neutrons, and is not seen electromagnetically [33]. 20
4 Detector description 4.1 String description The AMANDA detector consists of several strings buried deeply in the glacier ice, with a typical inter-string distance of ¥ 30 m. In the beginning of 1996, four holes were drilled and new strings were deployed in the first stage of the construction of the deeper detector AMANDA- B, which we will refer to here as AMANDA-B4. Each string supported 20 optical modules, numbered accordingly from the shallowest to the deepest, with the exception of the fourth string, which had 26 modules. The modules were all installed facing down, except for a few which were oriented facing up, for checks of their angular efficiency and atmospheric muon studies. The strings run from the surface of the ice sheet down to depths between 1900 m and 2000 m and were deployed in holes between 2000 m and 2180 m deep. The differences in lengths were intentional, the idea being that they would allow for measurements of the optical parameters of the ice over a larger range. The main cable of a string is composed of 20 coaxial RG59 YR-cables from Belden bundled together inside a supercable, with breakouts for PM connectors every 20 meters, starting from a depth between 1520 m and 1570 m, depending on string number. The purpose of those cables is to supply the PMs with high voltage and to transmit the PM pulses up to the surface electronics. Because of the thickness of the coaxial cables, their number is limited to at most 20 by the maximum size and weight of the main cable, which has to be carried in by air to the South Pole station and by the dimensions of the equipment (reels and winches) available for deployment. Separate cables holding optical fibers (one single mode and one multi-mode per OM) were deployed along with the strings. Each optical fiber can lead pulsed laser light from the surface and terminates with a nylon ball used to diffuse the light right below a module. The main purpose of their installation was to have a photon source to calibrate the PMs. Several other cables were also added for apparatus such as in-situ light sources used for PM time calibration and/or optical studies of the ice and inter-strings distance measurements, and pressure and temperature sensors. These service cables are enclosed in the supercable. Two radio receivers from the RICE (Radio Ice Cherenkov Experiment) were also deployed at shallow depths [34] for feasibility studies of an anticipated PeV neutrino detector. The four strings were thus equipped with 86 OMs and various light sources distributed as follows: - String 1: 20 OMs containing a Hamamatsu PM each, all equipped with nylon balls and facing down. The exceptions to this are modules #1 and #10 which are facing up. One RICE detector at 250 m depth, LED modules right above OM #1 and below OMs #7,12 and 19. A nitrogen laser-module (337 nm) 10 meters below OM #16. - String 2: 20 OMs, all Hamamatsu, all equipped with nylon balls, facing down except for OM#1 and #10. One RICE detector at 140 m depth, LED modules under OMs#1,7,13 and 19 and a DC halogen lamp 10 m below OM#16. A second-harmonic generator was also installed. - String 3: 20 OM, all Hamamatsu except OM#1 and 2 which are of the type Thorn EMI 9353, all equipped with nylon balls, facing down except for OM#1 and #10, a DC halogen lamp under OM#16. 21
Page 1 and 2: Muon Analysis with the AMANDA-B Fou
Page 3 and 4: Contents 1 Dissertation description
Page 5 and 6: 1 Dissertation description This dis
Page 7 and 8: structure of NESTOR is a 12 floor t
Page 9 and 10: 3.1.2 Acceleration mechanisms In pr
Page 11 and 12: 3.1.3 Candidate point sources of ne
Page 13 and 14: 3.1.4 Neutrino cascades ~10 -2 pc J
Page 15 and 16: 3.1.6 Background The first source o
Page 17 and 18: which is the fraction of the nucleo
Page 19 and 20: Detection rate Detector Figure 7: D
Page 21 and 22: Cherenkov wavefront £ £ £¤¦¥
Page 23: Electromagnetic showers Both electr
Page 27 and 28: Figure 10: ©¡ -laser module insta
Page 29 and 30: 1m Figure 12: The drill head, equip
Page 31 and 32: Figure 14: Bleeder circuit meters.
Page 33 and 34: micros. Figure 16: Arrival time dis
Page 35 and 36: 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1
Page 37 and 38: of 100 V over PMs. The TDC module u
Page 39 and 40: 10 4 10 3 10 2 0 5000 10000 15000 2
Page 41 and 42: 5 Optical properties of the South P
Page 43 and 44: λ a [m] 300 250 200 150 100 50 Dep
Page 45 and 46: (a.u) 0.5 0.4 0.3 0.2 0.1 0 0 1000
Page 47 and 48: absorption length, m 160 140 120 10
Page 49 and 50: leading edge (ns) Figure 34: Exampl
Page 51 and 52: High Voltage [V] Gain 1300 0.03 140
Page 53 and 54: transit time (ns) YAG-data, larger
Page 55 and 56: £ £ £ £ £ £ 79.5 72.0 80.3
Page 57 and 58: String# 2 3 4 1 1.9 1.8 -51.5 1.5
Page 59 and 60: String# 2 3 4 1 0.2 1.0 -51.5 0.9
Page 61 and 62: experience from the field, where th
Page 63 and 64: emitter ¦ £ ¤ ¢ ¡ ¦ £ ¤ ¢
Page 65 and 66: 1 ¢ ¢ ¢ ¢ ¢ ¢ ¥ ¢ ¢ ¢ ¢
Page 67 and 68: 7 Data filters 7.1 Data cleaning Th
Page 69 and 70: Figure 46: All leading edge times f
Page 71 and 72: the average relative time between p
Page 73 and 74: 8 Reconstruction of muons-tracks 8.
Page 75 and 76:
x' z' D č Figure 51: In a coordina
Page 77 and 78:
Number of events 1200 1000 800 600
Page 79 and 80:
Probability (t > t 0 ) 1 0.8 0.6 0.
Page 81 and 82:
1/N dN/dt < t > (ns) Skewness 1 0.8
Page 83 and 84:
Several measures of the distributio
Page 85 and 86:
¤ ¦ § £ ¢¡ ¤£ ¢¡ § ¤
Page 87 and 88:
Table 15 yields the results, with n
Page 89 and 90:
Figure 60: £¢¡ ¤¤£¦¥¨§©
Page 91 and 92:
9 Analysis of 1996 data There are t
Page 93 and 94:
Figure 64: Atmospheric muon flux at
Page 95 and 96:
ule to scatter back and give a hit,
Page 97 and 98:
£ ¡ ¤¨£ £ ¦¡ Figure 70: for
Page 99 and 100:
9.2.2 SPASE coincidences The SPASE
Page 101 and 102:
-15 and 15 ns after the STREC recon
Page 103 and 104:
9.3 Search for atmospheric neutrino
Page 105 and 106:
Figure 78: Left: probability distri
Page 107 and 108:
Figure 80: Distributions of several
Page 109 and 110:
8 7 6 5 4 3 2 1 Figure 82: The two
Page 111 and 112:
threshold for an AMANDA-B4 search o
Page 113 and 114:
¡ [ ¦ Neutralino 50 100 250
Page 115 and 116:
10 Conclusions A position calibrati
Page 117 and 118:
References [1] E. Andrés, P. Askeb
Page 119 and 120:
[50] A. J. Gow and T. Williamson, J
Page 121 and 122:
Appendix correction (ns) correction
Page 123 and 124:
Em. string Em. module Rec. string R
Page 125 and 126:
distance (m) Run 159 Z-shift=33.5.
Page 127 and 128:
distance (m) To string 1 distance (
Page 129 and 130:
distance (m) To string 1 distance (
Page 131 and 132:
¦ ¦ § ¦ © © © © ¢ ¡£¢
Page 133 and 134:
Em. string Em. module Rec. string R
show all

Link to Fulltext

Create successful ePaper yourself

Delete template?

Save as template?