SPEAR (originally Stanford Positron Electron Asymmetric Rings, now simply a name) was a collider at the SLAC National Accelerator Laboratory.
 It began running in 1972, colliding electrons and positrons with an energy of .
 During the 1970s, experiments at the accelerator played a key role in particle physics research, including the discovery of the meson (awarded the 1976 Nobel Prize in physics), many charmonium states, and the discovery of the tau (awarded the 1995 Nobel Prize in physics).
Characteristic X-rays are emitted when outer-shell electrons fill a vacancy in the inner shell of an atom, releasing X-rays in a pattern that is "characteristic" to each element.
 Characteristic X-rays were discovered by Charles Glover Barkla in 1909, who later won the Nobel Prize in Physics for his discovery in 1917.
Mohammad Abdus Salam {'1': ", '2': ", '3': 'NI, SPk, KBE', '4': "} (Punjabi, Urdu: ‎ ; ] ; 29 January 192621 November 1996), was a Pakistani theoretical physicist.
 A major figure in 20th century theoretical physics, he shared the 1979 Nobel Prize in Physics with Sheldon Glashow and Steven Weinberg for his contribution to the electroweak unification theory.
 He was the first Pakistani and first Muslim to receive a Nobel Prize in science and the second from an Islamic country to receive any Nobel Prize (after Anwar Sadat of Egypt).
Since 1901, the Nobel Prize in Literature (Swedish: "Nobelpriset i litteratur" ) has been awarded annually to an author from any country who has, in the words of the will of Alfred Nobel, produced "in the field of literature the most outstanding work in an ideal direction" (original Swedish: "den som inom litteraturen har producerat det mest framstående verket i en idealisk riktning").
 Though individual works are sometimes cited as being particularly noteworthy, here "work" refers to an author's work as a whole.
 The Swedish Academy decides who, if anyone, will receive the prize in any given year.
 The academy announces the name of the chosen laureate in early October.
 It is one of the five Nobel Prizes established by the will of Alfred Nobel in 1895; the others are the Nobel Prize in Chemistry, Nobel Prize in Physics, Nobel Peace Prize, and Nobel Prize in Physiology or Medicine.
The Nobel Prize in Physics (Swedish: "Nobelpriset i fysik" ) is a yearly award given by the Royal Swedish Academy of Sciences for those who conferred the most outstanding contributions for mankind in the field of physics.
 It is one of the five Nobel Prizes established by the will of Alfred Nobel in 1895 and awarded since 1901; the others being the Nobel Prize in Chemistry, Nobel Prize in Literature, Nobel Peace Prize, and Nobel Prize in Physiology or Medicine.
The Nobel Prize in Physiology or Medicine (Swedish: "Nobelpriset i fysiologi eller medicin" ) is awarded annually by the Swedish Karolinska Institute to scientists and doctors in the various fields of physiology or medicine.
 It is one of the five Nobel Prizes established by the 1895 will of Alfred Nobel (who died in 1896), awarded for outstanding contributions in chemistry, physics, literature, peace, and physiology or medicine.
 As dictated by Nobel's will, the award is administered by the Nobel Foundation and awarded by a committee that consists of five members and an executive secretary elected by the Karolinska Institute.
 While commonly referred to as the Nobel Prize in Medicine, Nobel specifically stated that the prize be awarded for "physiology or medicine" in his will.
 Because of this, the prize can be awarded in a broader range of fields.
 The first Nobel Prize in Physiology or Medicine was awarded in 1901 to Emil Adolf von Behring, of Germany.
 Each recipient receives a medal, a diploma and a monetary award that has varied throughout the years.
 In 1901, von Behring received 150,782 SEK, which is equal to 7,731,004 SEK in December 2008.
 In 2013, the prize was awarded to James E. Rothman, Randy W. Schekman and Thomas C. Südhof; they were recognised "after discovering how cells precisely transport material".
 The award is presented in Stockholm at an annual ceremony on December 10, the anniversary of Nobel's death.
Charles Glover Barkla FRS FRSE (7 June 1877 – 23 October 1944) was a British physicist, and the winner of the Nobel Prize in Physics in 1917 for his work in X-ray spectroscopy and related areas in the study of X-rays (Roentgen rays).
This is a list of Danish Nobel laureates.
 Since the Nobel Prize was established per the will of Swedish inventor Alfred Nobel in 1895, 12 of the prize winners have been from Denmark.
 The first Danish Nobel laureate was Niels Ryberg Finsen, who won a Nobel Prize for medicine in 1903 for his work in using light therapy to treat diseases.
 The most recent Danish Nobel Prize winner was Jens Skou who won the prize in chemistry for his discovery over the enzyme, Na+/K+-ATPase in 1997.
 To date, of the 13 Nobel Prizes won by Danish people, 5 have been for medicine, 3 have been for physics, 3 have been for literature, 1 has been for chemistry and one has been for peace.
Philipp Eduard Anton von Lenard (7 June 1862 – 20 May 1947) was a German physicist and the winner of the Nobel Prize for Physics in 1905 for his research on cathode rays and the discovery of many of their properties.
 He was a nationalist and anti-Semite; as an active proponent of the Nazi ideology, he had supported Adolf Hitler in the 1920s and was an important role model for the "Deutsche Physik" movement during the Nazi period.
 Notably, he had labeled Albert Einstein's contributions to science as constituting "Jewish physics".
Aage Niels Bohr (] ; 19 June 1922 – 8 September 2009) was a Danish nuclear physicist who shared the Nobel Prize in Physics in 1975 with Ben Mottelson and James Rainwater "for the discovery of the connection between collective motion and particle motion in atomic nuclei and the development of the theory of the structure of the atomic nucleus based on this connection".
 Starting from Rainwater's concept of an irregular-shaped liquid drop model of the nucleus, Bohr and Mottelson developed a detailed theory that was in close agreement with experiments.
 Since his father, Niels Bohr, had won the prize in 1922, he and his father were one of the six pairs of fathers and sons who have both won the Nobel Prize and one of the four pairs who have both won the Nobel Prize in Physics.

Question: The physicist who won the 1917 Nobel Prize in Physics for the discovery of Characteristic X Rays was of what nationality?
Answer: British