Technology Comparison: brief update

Transcription

1 Technology Comparison: brief update People contributing: Ciaran, Cosmin, Kentaro, S.V. Running a bit late (Spent most of my time writing code, instead of text for paper.) Simulation framework mostly completed now Recoil generator: SRIM Electron generator: CASINO Detector + readout simulation: own code in python First results for neutrino/wimp discrimination with 1D readout shown at CYGNUS217 (see slides attached to this agenda). Today, focusing on Cosmic visions white paper Electron discrimination at low recoil energy. This is a key issues we need address for coming funding proposals and in our paper. CYGNUS paper meeting 1

2 CYGNUS HD1: Sensitivity for Cosmic Visions (estimated by Nguyen Phan) Summary plot by Eric Dahl 1 m 3 w/ 3-years of running. Competitive sensitivity. Could be a step towards a large CYGNUS observatory. CYGNUS 217 Sven Vahsen (U. Hawaii) 2

3 New Results (post CYGNUS217): Electron discrimination in 2 torr of SF 6 L versus E: definition of L is important 1 kev electron.1.5 energy distribution Start of track L kink 3d Entries 164 Mean x.5968 Mean y.2259 Mean z.6187 Std Dev x.335 Std Dev y.1616 Std Dev z.2118 end of track Flourine recoils, from 1 GeV WIMP L = distance from start to CYGNUS to ionization paper meetingfurthest away 3

4 New Results (post CYGNUS217): Electron discrimination in 2 torr of SF 6 L versus E: definition of L is important 1 kev electron.1.5 energy distribution Start of track L kink 3d Entries 164 Mean x.5968 Mean y.2259 Mean z.6187 Std Dev x.335 Std Dev y.1616 Std Dev z.2118 end of track Flourine recoils, from 1 GeV WIMP L = 2*distance(center of CYGNUS charge paper cloud meeting to point furthest from center) 4

5 With diffusion included. -5 driftlength. Upshot: Quite good electron rejection (>~ 1 3 ) looks feasible above 2 kev (in 3D) Still need to properly quantify, but for reference, there are 5 electrons in each energy bin 1 kev electron.1.5 energy distribution Start of track L kink 3d Entries 164 Mean x.5968 Mean y.2259 Mean z.6187 Std Dev x.335 Std Dev y.1616 Std Dev z.2118 end of track Flourine recoils, from 1 GeV WIMP L = 2*distance(center of CYGNUS charge paper cloud meeting to point furthest from center) 5

6 Discrimination at low E < 2 kevee: 1 GeV WIMPs w/o diffusion With diffusion He recoils, 1 GeV WIMP Flourine recoils, 1 GeV WIMP Below 5 kev, electron discrimination improves again! Particularly for He recoils! Limited by diffusion. Next steps: validate w/ DEGRAD, include effect of charge readout and post-detection track reconstruction. CYGNUS paper meeting 6

7 Outlook Most hard work done now, but still need significant time to analyze results and write text. Planning two types of crosschecks of existing simulations Simulate nuclear recoils both with 1D SRIM de/dx (done) and Cosmin s 3D recoil library (have a first version, not tested yet) Simulate electrons both with CASINO (done) DEGRAD (CERN packge). Have a summer student will do this in July. We all need to agree on gas mixtures presented in different parts of the CYGNUS paper. Proposal: 6 torr He + 2 torr SF6 [CYGNUS HD-1 mixture] 6 torr He + 2 torr SF6 [candidate for large directional CYGNUS] I can t promise that I will do any useful work in July. I will be back and free to resume work July 28 th. Can we finish the draft by mid August, and submit to Journal by August 31? Ambitous, but possible? CYGNUS paper meeting 7

8 Input parameters used to simulate ionization, drift, gas gain Gas mixture: SF 6 Pressure: 2 torr W: ev per ion pair [Hilal and Christophorou, alpha particles] Gas gain: 9 (A. Scarf) Gain resolution:! " # = 2% (A. Scarf, Sheffield) Disclaimer: highly preliminary -- needs more work! Diffusion: () *) Drift velocity: 14 μm/μs [from D. Loomba, New Mexico: for 6-8 V/ which gave minimum diffusion at 2 Torr] 6/3/17 CYGNUS 217 8

9 Input parameters for readout plane simulation Disclaimer: highly preliminary -- needs more work! Readout type Dimensionality Segmentation Z binning (assume 1MHz sampling) Detector Element Capacitance Noise level Noise level per 1-μs readout clock cycle Threshold (avalanche charge) planar 1D (z) 1 x 1 14 μm 11, pf GEMs: 25pF (3*3, 1um) 3pF (1*1, 1um) 25pF (3*3, 1um) 54 e - for 1 pf, 1μs peaking time 18 e - 3 x noise wires 2D (xz) 1m wires, 2mm pitch 14 μm? 25e - in 1 us 8 e - 3 x noise CMOS camera 2D (xy) t.b.d. n/a n/a??? resistive strip Micromegas 3D (xyz) with coincidence ambiguity 1 m strips, 2 μm pitch 14 μm 5 pf per 1 of strip à 5 pf 28e - for 1μs peaking time pixel ASIC 3D (xyz) 2 μm 14 μm 12-2 ff ~27 e - (per 25 ns sample) 28 e - 3 x noise 42 e - 15 e - (only charge readout for now. But can probably add 2d optical.)

10 New: Particle ID Michael Hedges TPC Simulation by Igal Jaegle (now at U. Florida) preliminary BEAST II Collaboration, First Measurements of Beam Backgrounds at SuperKEKB, in preparation for NIMA CYGNUS 217 Sven Vahsen (U. Hawaii) 1

11 de/dz vs de/ds One 1-keV electron de/dz dedz Entries 179 Mean.884 Std Dev.3943 de/ds.5 deds Entries 179 Mean.1136 Std Dev Z () S () CYGNUS paper meeting 11

12 energy distribution 3d Entries 164 Mean x.5968 Mean y.2259 de/dz vs de/ds.1.5 Mean z.6187 Std Dev x.335 Std Dev y.1616 Std Dev z.2118 Another 1-keV electron de/dz dedz Entries 164 Mean.6187 Std Dev.2118 de/ds deds Entries 513 Mean.1174 Std Dev Z () S () CYGNUS paper meeting 12