COSCUP 2015 簡報。
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Sunday, August 16, 2015
Saturday, August 08, 2015
LHC 動畫：質子的軌跡
本影片說明大型強子對撞型加速器的運作原理。
影片開始的空照圖，顯示位於日內瓦近郊的歐洲粒子物理研究中心 (CERN)，並勾勒出 CERN 加速器群的輪廓，同時顯示了週長 27 公里的大型強子對撞型加速器 (LHC)。當質子在 LHC 上運行，我們可以依序看到位於 LHC 上的四個主要實驗：重離子對撞器 (ALICE)，超環面 LHC 儀器 (ATLAS)，緊湊渺子螺線管 (CMS)，以及 LHC 底夸克實驗 (LHCb)。
質子束的來源是一瓶氫氣罐。強力的電場將氫氣原子核外圍繞的電子摘除，留下其原子核：質子。Linac 2 直線加速器，是整個加速鏈的第一級，可以將質子加速到 50 MeV。質子束流進一步注入質子同步加速增能環 (PSB)，可以將質子加速到 1.4 GeV，接著注入質子同步加速器中 (PS)。PS 可以再把質子的能量，推進到 25 GeV，然後注入超級質子同步加速器 (SPS) 之中。質子的能量在 SPS 可以達到 450 GeV。
加速後的質子束，最後會分別傳送到 LHC 加速器的兩個束流管中，分別以順時針與逆時針環繞 LHC 運行，最終能量可以達到 6.5 TeV。在束流管中的質子，在正常運作的情況下可以維持在 LHC 中達數個小時之久。這兩個束流管中的質子，會分別在四個主要的實驗點：ALICE, ATLAS, CMS 與 LHCb 的所在處對撞，對撞的能量相當於 13 TeV。
質子碰撞的頻率是每 25 奈秒發生一次，實驗偵測器的一級觸發邏輯電路 L1，會在及短時間內選出初選的事例，送到二及與三級的電腦叢集做進一步的篩選。篩選出來的數據，將會送到 CERN 的資料中心，做初階的數據重建與長期數據備份，同時這些原始數據也會發送到 LHC 計算網格。全球 LHC 計算網格的基礎建設架構 (WLCG)，包含了兩個零級 Tier-0 資料中心，分別位於 CERN 計算機中心與匈牙利的布達佩斯。WLCG 的一級與二級資料中心，則位於全球數個研究機構與參與的各大學單位。
當對撞的數據隨著時間的累積，物理學家就可以收集到足夠的統計量，來檢驗理論學家所提出的理論模型預測。舉例來說，理論預測的希格斯粒子，就在 LHC 的第一期 7/8 TeV 運作階段中發現，如同影片中所顯示的隆起部分。LHC 提供物理學家探測物質自然定律的一個重要管道，在新的運作能量 13 TeV 下，人類的知識將可以再往新的粒子物理邊境推進。
https://amara.org/en/videos/ngrZNFAWTli2/info/lhc-animation-the-path-of-the-protons/
(含中文字幕解說)
https://www.youtube.com/watch?v=pQhbhpU9Wrg
This animation shows how the Large Hadron Collider (LHC) works.
The film begins with an aerial view of CERN near Geneva, with outlines of the accelerator complex, including the underground Large Hadron Collider (LHC), 27-km in circumference. The positions of the four largest LHC experiments, ALICE, ATLAS, CMS and LHCb are revealed before we see protons travelling around the LHC ring.
The proton source is a simple bottle of hydrogen gas. An electric field is used to strip hydrogen atoms of their electrons to yield protons. Linac 2, the first accelerator in the chain, accelerates the protons to the energy of 50 MeV. The beam is then injected into the Proton Synchrotron Booster (PSB), which accelerates the protons to 1.4 GeV, followed by the Proton Synchrotron (PS), which pushes the beam to 25 GeV. Protons are then sent to the Super Proton Synchrotron (SPS) where they are accelerated to 450 GeV.
The protons are finally transferred to the two beam pipes of the LHC. The beam in one pipe circulates clockwise while the beam in the other pipe circulates anticlockwise, increasing in energy until they reach 6.5 TeV. Beams circulate for many hours inside the LHC beam pipes under normal operating conditions. The two beams are brought into collision inside four detectors – ALICE, ATLAS, CMS and LHCb – where the total energy at the collision point is equal to 13 TeV.
Collisions occur once every 25 nanoseconds, the trigger level 1 performs ultrafast event selection before data move to trigger levels 2 and 3 at the PC farm. Selected event data are then sent to the CERN data centre that performs initial data reconstruction and makes a copy of the data for long-term storage, while raw and reconstituted data are sent to the Computing Grid. The Worldwide LHC Computing Grid infrastructure includes two "Tier 0" sites, one at CERN and one in Budapest, Hungary, as well as further smaller computing sites located around the world.
As collision data increases, physicists build up enough statistics to test theoretical predictions, such as the prediction of a Higgs Boson, discovered in the data from the LHC's first physics run (shown as a bump in the graphs in the animation). The LHC allows physicists to probe the nature of matter. The new higher collision energy of 13 TeV opens up new frontiers in particle physics.
Directors: Daniel Dominguez, Arzur Catel Torres
Music: F_Fact_-_State_of_Mind_(_psystep_vers._o
Copyright © 2015 CERN. Terms of use: http://copyright.web.cern.ch/
View the video on CDS http://cds.cern.ch/record/2020780
影片開始的空照圖，顯示位於日內瓦近郊的歐洲粒子物理研究中心 (CERN)，並勾勒出 CERN 加速器群的輪廓，同時顯示了週長 27 公里的大型強子對撞型加速器 (LHC)。當質子在 LHC 上運行，我們可以依序看到位於 LHC 上的四個主要實驗：重離子對撞器 (ALICE)，超環面 LHC 儀器 (ATLAS)，緊湊渺子螺線管 (CMS)，以及 LHC 底夸克實驗 (LHCb)。
質子束的來源是一瓶氫氣罐。強力的電場將氫氣原子核外圍繞的電子摘除，留下其原子核：質子。Linac 2 直線加速器，是整個加速鏈的第一級，可以將質子加速到 50 MeV。質子束流進一步注入質子同步加速增能環 (PSB)，可以將質子加速到 1.4 GeV，接著注入質子同步加速器中 (PS)。PS 可以再把質子的能量，推進到 25 GeV，然後注入超級質子同步加速器 (SPS) 之中。質子的能量在 SPS 可以達到 450 GeV。
加速後的質子束，最後會分別傳送到 LHC 加速器的兩個束流管中，分別以順時針與逆時針環繞 LHC 運行，最終能量可以達到 6.5 TeV。在束流管中的質子，在正常運作的情況下可以維持在 LHC 中達數個小時之久。這兩個束流管中的質子，會分別在四個主要的實驗點：ALICE, ATLAS, CMS 與 LHCb 的所在處對撞，對撞的能量相當於 13 TeV。
質子碰撞的頻率是每 25 奈秒發生一次，實驗偵測器的一級觸發邏輯電路 L1，會在及短時間內選出初選的事例，送到二及與三級的電腦叢集做進一步的篩選。篩選出來的數據，將會送到 CERN 的資料中心，做初階的數據重建與長期數據備份，同時這些原始數據也會發送到 LHC 計算網格。全球 LHC 計算網格的基礎建設架構 (WLCG)，包含了兩個零級 Tier-0 資料中心，分別位於 CERN 計算機中心與匈牙利的布達佩斯。WLCG 的一級與二級資料中心，則位於全球數個研究機構與參與的各大學單位。
當對撞的數據隨著時間的累積，物理學家就可以收集到足夠的統計量，來檢驗理論學家所提出的理論模型預測。舉例來說，理論預測的希格斯粒子，就在 LHC 的第一期 7/8 TeV 運作階段中發現，如同影片中所顯示的隆起部分。LHC 提供物理學家探測物質自然定律的一個重要管道，在新的運作能量 13 TeV 下，人類的知識將可以再往新的粒子物理邊境推進。
https://amara.org/en/videos/ngrZNFAWTli2/info/lhc-animation-the-path-of-the-protons/
(含中文字幕解說)
https://www.youtube.com/watch?v=pQhbhpU9Wrg
This animation shows how the Large Hadron Collider (LHC) works.
The film begins with an aerial view of CERN near Geneva, with outlines of the accelerator complex, including the underground Large Hadron Collider (LHC), 27-km in circumference. The positions of the four largest LHC experiments, ALICE, ATLAS, CMS and LHCb are revealed before we see protons travelling around the LHC ring.
The proton source is a simple bottle of hydrogen gas. An electric field is used to strip hydrogen atoms of their electrons to yield protons. Linac 2, the first accelerator in the chain, accelerates the protons to the energy of 50 MeV. The beam is then injected into the Proton Synchrotron Booster (PSB), which accelerates the protons to 1.4 GeV, followed by the Proton Synchrotron (PS), which pushes the beam to 25 GeV. Protons are then sent to the Super Proton Synchrotron (SPS) where they are accelerated to 450 GeV.
The protons are finally transferred to the two beam pipes of the LHC. The beam in one pipe circulates clockwise while the beam in the other pipe circulates anticlockwise, increasing in energy until they reach 6.5 TeV. Beams circulate for many hours inside the LHC beam pipes under normal operating conditions. The two beams are brought into collision inside four detectors – ALICE, ATLAS, CMS and LHCb – where the total energy at the collision point is equal to 13 TeV.
Collisions occur once every 25 nanoseconds, the trigger level 1 performs ultrafast event selection before data move to trigger levels 2 and 3 at the PC farm. Selected event data are then sent to the CERN data centre that performs initial data reconstruction and makes a copy of the data for long-term storage, while raw and reconstituted data are sent to the Computing Grid. The Worldwide LHC Computing Grid infrastructure includes two "Tier 0" sites, one at CERN and one in Budapest, Hungary, as well as further smaller computing sites located around the world.
As collision data increases, physicists build up enough statistics to test theoretical predictions, such as the prediction of a Higgs Boson, discovered in the data from the LHC's first physics run (shown as a bump in the graphs in the animation). The LHC allows physicists to probe the nature of matter. The new higher collision energy of 13 TeV opens up new frontiers in particle physics.
Directors: Daniel Dominguez, Arzur Catel Torres
Music: F_Fact_-_State_of_Mind_(_psystep_vers._o
Copyright © 2015 CERN. Terms of use: http://copyright.web.cern.ch/
View the video on CDS http://cds.cern.ch/record/2020780
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