The engraved stone they had removed from the surface had been sitting on a flat sill, six inches wide and two inches deep that ran uninterrupted along all four edges of the hole. The passageway in between was five feet wide, enough for two people to walk down side by side without touching each other. She took a mental note to thank Ben once more for letting her go down alone.
After thirty-odd steps, she found herself on a small landing, five feet square, where the steps took a ninety-degree left turn, away from the cliff outside, and continued to descend.
The walls of the staircase were completely smooth. As far as she could see, there was not one hieroglyph, engraving or painting all the way down. From what she knew of Egyptian tombs and monuments, this was not entirely uncommon; there may well be more to see further down.
The bottom of the steps opened onto a large room, about three times as wide as the staircase and just as long. She shone her powerful torch around, the passage of the Professor betrayed by the recently disturbed dust that danced lazily in its beam. In the four corners of the room and twice at regular intervals on each side, straight undecorated columns connected the floor and ceiling. On closer inspection, Gail noticed that they had not been built, but rather carved out of the bedrock, and were connected to the wall behind. The entrance she had emerged from was in the middle of one of the walls, in between two columns.
There were no other openings.
As with the staircase that led to it, the walls of the room were unmarked and the twelve columns stood out as the only decorative features.
The engineers’ X-ray machine was on the floor opposite her, one flat end of the cylinder touching the wall between two columns, the other pointing towards the centre of the room. Sitting on the floor next to it was a laptop computer, open and unlocked. She walked over to it and looked at the screen.
At first, she was not sure what she was looking at, the monochrome display showing a series of dark and light shapes within a circular frame, but soon her mind adjusted to the input, in much the same way it usually did after several seconds staring at a three dimensional image. She twisted her head slightly, then looked at the wall the cylinder was propped against.
“No way,” she said to herself.
She knelt down in front of the laptop and studied the grey and black shapes more closely for several minutes, briefly looking back at the wall several times in disbelief before resuming her in-depth appreciation of what lay beyond the rock.
It was a sight that, as a student, she was all too familiar with.
The echo of footsteps and excited voices from the corridor behind her brought Gail back to reality; she turned round just in time to see three students, a young boy and two girls, enter the room. Behind them, she could make out the distinctive tones of Ben trying to explain something to her husband.
“Look!” she said, standing up and pointing to the laptop display. “Look at this! Isn’t it amazing?”
The three students gathered round and stood in silence as they struggled to interpret the picture. After a brief moment, one of them recognised an object with a shriek, and within seconds they were all pointing eagerly at various shapes and talking quickly in a mixture of English, for Gail was still with them, and Arabic, because they were too excited to be able to find all the words they needed to explain what they were looking at.
In this time, Ben and George had entered the room and now stood behind the small group of archaeologists.
“All those steps lead to this, a room with no doors?” George complained.
She grabbed him by the arm and pulled him towards the laptop. “This room isn’t it.” As she gestured towards the wall, he saw the look of excitement in her eyes and looked more closely at the display before him. “It’s just an ante-chamber,” she said.
George leant closer, the puzzled look on his face telling Gail that he was unable to interpret the monochrome feed. “What am I looking at?”
The Backscatter X-ray system being used by the engineers was an experimental piece of hardware, developed mainly for seeing through rubble after earthquakes. The traditional X-ray, as used on patients in hospitals, was able to ‘see through’ objects by detecting varying levels of resistance to the radiation passing through them, therefore giving a very obvious representation of the human skeleton for instance, where the density of the bone is significantly higher than that of soft tissue. In order to be able to measure resistance through an object, traditional X-rays require the use of a radioactive emitter and a photographic receiver, in between which the object to be examined is placed.
In contrast, the Backscatter X-ray, as the name suggests, exploits a different phenomenon in the field of radiation detection – that of the amount of subjected radiation returned from an object. At the end of the twentieth century, this new form of X-ray garnered some interest from the search and rescue community, but it was not until the twenty-first century that it was fully taken advantage of; indeed, an urge to improve airport security in the United States following a string of terrorist attacks forced the government to invest heavily in advanced security technologies. The Backscatter X-ray had many advantages over other detection methods, primarily in its speed. Whereas it would take nearly thirty seconds for a person to manually search a passenger, the new system was able to accurately scan and detect offensive items in less than a second.
The other benefit of the Backscatter X-ray over traditional X-ray was that as it measured radiation returning from a target object, the emitter and receiver could be contained within one box, giving it the same flexibility as radar and sonar. Rather than placing the object between the X-ray and a photographic plate, it was simply a matter of pointing the X-ray at the object you wanted to see through.
Unfortunately, public opposition to the X-ray eventually proved too strong and the technology was never successfully implemented. It was not that the amount of radiation passengers were subjected to was unacceptable; in fact the Backscatter technique produced far less radiation than traditional X-rays and was deemed to be harmless. Even the price of the technology was not prohibitive, as the end cost of a production passenger scanning unit was cheaper than running a traditional security checkpoint. In the end, the system was abandoned as it presented an infringement on passenger privacy. Because of the low levels of radiation employed by the system, it did not see through soft tissue to show bones; instead, it saw through clothes to show soft tissue. During its first years in live trials, it became obvious that the quality of the images produced by the system was so high that it was no different to asking people to pass through security completely naked, and with airport management unable to commit to the reliable safekeeping of all of the resulting indecent images, the Backscatter X-ray lost its high government funding, and it was relegated once more to the search and rescue community, where funding was low and public interest minimal.
The cylindrical system they were looking at now had therefore been specifically designed for search and rescue, and was more portable and significantly more powerful than its airport ancestors. The level of radiation it was outputting, whilst still significantly lower than that of a traditional X-ray, allowed it to see through solid objects and detect whatever lay beyond, within a distance of up to one hundred and fifty feet. The software installed on the laptop computer was developed not only to render the resulting images in monochrome, but also display relative distances and scale; the further objects were from the cylinder, the lighter their colour on the display. To help in measuring these variations, a scale was shown at the bottom of the screen, from black to very light grey, zero feet to one hundred and fifty. The view was very cluttered, as the user interface had not been particularly well designed, but as Gail and the group of students had shown, only a brief period of mental adjustment was needed to interpret the images.